Faculty Profiles - TADA Naoya

Papers - TADA Naoya

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Crystal plastic homogenization finite element analysis of Ti-6242 alloy subjected to in-plane reverse loading Reviewed

Takeshi UEMORI, Naoya TADA, Junji SAKAMOTO

Bulletin of the JSME, Mechanical Engineering Journal 12 ( 2 ) 24-00340 2025.4

Effect of artificial defect on tensile properties of thin titanium alloy wire Reviewed

Junji SAKAMOTO, Naoya TADA, Takeshi UEMORI, Koyo OISHI

Bulletin of the JSME, Mechanical Engineering Journal 11 ( 6 ) 24-00129 2024.12

Crystal Grain Rotation during Tensile Test of Polycrystalline Pure Titanium Thin Sheet Based on Surface Height and Crystal Orientation Reviewed

Naoya Tada, Hiroaki Ohashi, Takeshi Uemori, Junji Sakamoto

Journal of Physics: Conference Series 2892 012002 2024.11

Elasticity-based prediction of inhomogeneous deformation of polycrystalline metals Invited

Naoya TADA

Extended abstract of Asia-Pacific Conference on Fracture and Strength 2024 (APCFS 2024) P001 2024.11

Creep Fracture and Damage Evaluation Based on the Distribution of Cavies on Grain Boundaries Invited Reviewed

Naoya Tada

Abstract book of 2024 International Symposium on Structural Integrity (ISSI 2024) 178 2024.11

Method for Predicting Crack Size Using Amplitude Change in Titanium Alloy under Bending Vibration Reviewed

J. Sakamoto, N. Tada, T. Uemori

Book of Abstracts: Europian Conference on Fracture 2024 (ECF24) 472 2024.9

Fracture Morphology of Ti-6Al-4V Thin Wire under Load-controlled Fatigue Test Reviewed

Junnji SAKAMOTO, Naoya TADA, Takeshi UEMORI

Titanium Japan 72 ( 3 ) 39 - 43 2024.7

Relationship between cyclic tensile properties of cellulose nanofiber reinforced natural rubber and volume fraction of bound rubber obtained from swelling tests Reviewed

Kento OKUI, Naoya TADA, Takeshi UEMORI, Junji SAKAMOTO, Keita SAKAKIBARA

Transactions of the JSME 90 ( 932 ) 24-00008 2024.4

Vibration change and crack propagation under bending vibration of aluminum alloy Reviewed

SAKAMOTO Junji, TADA Naoya, UEMORI Takeshi

Transactions of the JSME (in Japanese) 90 ( 930 ) 23-00246 2024.2

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Japan Society of Mechanical Engineers

In this study, aluminum alloy specimens were subjected to bending vibrations at different vibration frequencies near the first resonance frequency in order to investigate the vibration changes associated with crack propagation. Bending displacement, crack length, and strains at several parts of the specimen were measured during the bending vibration tests. As a result, it was confirmed that when the vibration frequency was lower than the initial first resonance frequency, the vibration amplitude increased with the crack length, and when the vibration frequency was higher than the initial first resonance frequency, the vibration amplitude decreased with an increase in the crack length. This is due to the decrease in the first resonance frequency due to the material damage. The relationship between the change of bending displacement amplitude and the crack length during vibration of the specimens can be organized using the slope (dΔε_x2/df_v) of the relationship between the strain range and the vibration frequency for the undamaged specimen. This might be due to the strong correlation between the decrease in the first resonance frequency and the crack size when the crack initiation location is limited in the material. Moreover, based on the relationship between the change of bending displacement amplitude and the crack length, the stress intensity factor range (ΔK) was estimated by incorporating the load change into the crack length. By using the modified ΔK, the crack growth rate during bending vibration could be predicted.

DOI： 10.1299/transjsme.23-00246

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Finite Element Simulation of Resistance Spot Welding of Aluminized Hot-Stamped Steel Sheets Reviewed

Manabu Fukumoto, Naoya Tada

Transactions of Society of Automotive Engineers of Japan 55 ( 1 ) 107 - 112 2024.1

Prediction of slip activity of crystal grains around semi-circular and semi-elliptical notches in thin-sheet specimens of pure titanium using formulated macroscopic stress distribution and crystal orientation Reviewed

Naoya Tada, Takeshi Uemori, Junji Sakamoto

Engineering Failure Analysis 153 107623 2023.11

A Mathematical Model of Shunting in Resistance Spot Welding Reviewed

Manabu FUKUMOTO, Naoya TADA

Quarterly Journal of the Japan Welding Society 41 ( 4 ) 302 - 310 2023.11

Prediction of active slip system for commercially pure titanium sheet by crystal plasticity finite element analysis Reviewed

Takeshi UEMORI, Naoya TADA, Junji SAKAMOTO, Masatoshi DOI

Extended abstract of The Advanced Technology in Experimental Mechanics and International DIC Society Joint Conference 2023 (ATEM-iDICs '23) 19-G05 2023.10

Microscopic Inhomogeneous Deformation of Polycrystalline Metals in Elastic and Plastic Regions Reviewed

Naoya Tada

Abstract of Materials Today Conference 2023 O4C.1 2023.8

Effect of Surface Roughness and Oxidation Treatment on Joint Strength between Aluminum Alloy and High-Density Polyethylene Reviewed

N. Tada, T. Uemori, J. Sakamoto

Extended Abstracts of 17th International Conference on Advances in Experimental Mechanics 2023.8

Tensile properties and slip deformation behavior of pure titanium thin wire with a small diameter-to-grain-size ratio Reviewed

Junji Sakamoto, Naoya Tada, Takeshi Uemori

Materials Science and Engineering A 863 144532 2023.1

Slip Activity of Crystal Grains around Notch in Thin Sheet Specimen of Pure Titanium Invited Reviewed

Naoya Tada, Takeshi Uemori, Junji Sakamoto

19 - 19 2022.12

Application of Complex-Step Derivative Approximation Method to Crystal Plasticity Analysis of Commercially Pure Titanium Sheet Reviewed

Takeshi UEMORI, Naoya TADA, Junji SAKAMOTO

Titanium Japan 70 ( 2 ) 158 - 163 2022.4

Effect of Mechanical Surface Treatment and Post-treatment Polishing on Tensile Strength and Fatigue Life of High-speed Tool Steel Reviewed

N.Karunathilaka, N.Tada, T.Uemori, J.Sakamoto, R.Hanamitsu, M.Fujii, Y.Omiya, M.Kawano

International Journal of Peening Science and Technology 2 ( 1 ) 35 - 60 2022

Effect of resin lamination on tensile strength characteristics of SUS304 stainless steel thin film Reviewed

Junji Sakamoto, Naoya Tada, Takeshi Uemori

The International Journal of Advanced Manufacturing Technology 116 ( 3-4 ) 1081 - 1088 2021.9

Prediction of the Fracture Location by Tensile Tests of Gray Cast Iron Based on the Dimensional Changes of Graphite Flakes Reviewed

Naoya Tada, Takeshi Uemori, Junji Sakamoto

Journal of Pressure Vessel Technology 143 ( 2 ) 2021.4

Microscopic deformation of thin sheet of polycrystalline pure titanium under tension Reviewed

Naoya Tada, Kentaro Kishimoto, Takeshi Uemori, Junji Sakamoto

American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP 3 PVP2020-21715 2020.10

Finite element study of the effect of internal cracks on surface profile change due to low loading of turbine blade Reviewed

Junji Sakamoto, Naoya Tada, Takeshi Uemori, Hayato Kuniyasu

Applied Sciences (Switzerland) 10 ( 14 ) 4883 2020.7

短繊維強化複合材料の可視化データによる破壊予測技術 Reviewed

多田直哉

プラスチックエージ 66 ( 799 ) 53 - 56 2020.3

Analysis of the change of direct current potential difference and diameter distribution of thin pure titanium wire subjected to tensile and fatigue loads for fracture prediction Reviewed

SAKAMOTO Junji, TAKAGI Yusuke, UEMORI Takeshi, TADA Naoya

Transactions of the JSME (in Japanese) 86 ( 882 ) 19-00351 2020.2

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：The Japan Society of Mechanical Engineers

<p>Pure titanium thin wires have been used for medical fields. It is important to investigate the possibility of non-destructive inspection of pure titanium thin wires for the safety utilization of them. In order to investigate a fracture prediction method for a pure titanium thin wire, we performed tensile and fatigue tests and a finite element analysis to analyze the changes of direct current potential difference and diameter distribution of the pure titanium thin wire during tensile and fatigue tests. It was found that a direct current potential difference method may be available for evaluating the tensile and fatigue damages of the pure titanium thin wire. In the tensile and fatigue tests, the normalized direct current potential difference increased almost linearly with an increase in the nominal strain, and a sign of an increase of the normalized direct current potential difference was observed when the fatigue crack propagated. Therefore, the nondestructive inspection could be conducted by setting a tolerance value of the normalized direct current potential difference, or detecting a sign of an increase in the normalized direct current potential difference. In addition, a method of predicting the fracture location from the diameter distribution change of the pure titanium thin wire was studied. The method could be applied to tensile and fatigue fractures.</p>

DOI： 10.1299/transjsme.19-00351

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積層セラミックコンデンサのプレス変形挙動 Reviewed

成瀬文雄, 多田直哉

FCレポート，日本ファインセラミックス協会 38 ( 1 ) 30 - 34 2020.1

Slip Deformation of Crystal Grains in Semi-Circular Notched Thin Sheet Specimen of Pure Titanium during Tensile Test Reviewed

Takashi Ishida, Naoya Tada, Takeshi Uemori, Junji Sakamoto

Proceedings of the International Conference on Advanced Technology in Experimental Mechanics 2019 (ATEM ‘19) ( 19-402 ) 2019.10

Effect of Lubrication and Forging Load on Surface Roughness, Residual Stress, and Deformation of Cold Forging Tools Reviewed

Karunathilaka, Tada, Uemori, Hanamitsu, Fujii, Omiya, Kawano

Metals 9 ( 7 ) 783 - 783 2019.7

Language：English Publishing type：Research paper (scientific journal) Publisher：MDPI AG

Cold forging is a metal forming that which uses localized compressive force at room temperature. During the cold forging process, the tool is subjected to extremely high loads and abrasive wear. Lubrication plays an important role in cold forging to improve product quality and tool life by preventing direct metallic contact. Surface roughness and residual stress also greatly affects the service life of a tool. In this study, variations in surface roughness, residual stress, and specimen deformation with the number of cold forging cycles were investigated under different forging conditions. Specimens that were made of heat-treated SKH51 (59–61 HRC), a high-speed tool steel with a polished working surface, were used. The specimens were subjected to an upsetting process. Compressive residual stress, surface roughness, and specimen deformation showed a positive relationship with the number of forging cycles up to a certain limit and became almost constant in most of the forging conditions. A larger change in residual stress and surface roughness was observed at the center of the specimens in all the forging conditions. The effect of the magnitude of the forging load on the above discussed parameters is large when compared to the effect of the lubrication conditions.

DOI： 10.3390/met9070783

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Prediction of Fracture Location in Tensile Test of Short-Fiber-Self-Reinforced Polyethylene Composite Plates Reviewed

Naoya Tada, Ming Jin, Takeshi Uemori, Junji Sakamoto

Conference Papers, ASME 2019 Pressure Vessels and Piping Conference (PVP2019) PVP2019-93546 2019.7

Authorship：Lead author Language：English Publishing type：Research paper (international conference proceedings) Publisher：American Society of Mechanical Engineers

<title>Abstract</title>
Composite materials such as carbon-fiber-reinforced plastics (CFRP) and glass-fiber-reinforced plastics (GFRP) have been attracting much attention from the viewpoint of lightweight solution of automobiles and airplanes. However, the recyclability of these composite materials is not sufficient and the environmental load is large. Recently, self-reinforced polymer (SRP), in which similar polymer is used for reinforcing fibers and matrix, has been proposed. High-density polyethylene (HDPE) reinforced with ultra-high-molecular-weight polyethylene (UHMWPE) fibers, so-called self-reinforced PE (SRPE), is one of the promising thermoplastic composites. In this study, SRPE plates were made and the tensile tests were carried out. After the effect of reinforcement of UHMWPE fibers was evaluated on the basis of the tensile strength, the relationship between the distribution of UHMWPE fibers and the location of the final fracture line was examined. It was found from these experimental results that the fracture tends to occur along the regions with low area fraction of fibers or along those with low area fraction of fiber/matrix boundaries. This fact suggests that the fracture location of SRPs is predictable from the distribution of reinforcing fibers.

DOI： 10.1115/pvp2019-93546

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Crystal Plasticity Finite Element Analysis of Effects of Microscopic Non-Uniform Deformation on Surface Roughness of Pure Titanium Sheet Reviewed

Takeshi UEMORI, Hiroki KAKIHARA, Naoya TADA

Journal of the Society of Materials Science, Japan 68 ( 6 ) 478 - 484 2019.6

Microscopic Elastic and Plastic Inhomogeneous Deformations and Height Changes on the Surface of a Polycrystalline Pure-Titanium Plate Specimen under Cyclic Tension Reviewed

Naoya Tada, Takeshi Uemori

Applied Sciences 8 ( 10 ) 1907 - 1907 2018.10

Authorship：Lead author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：MDPI AG

A cyclic tensile test was carried out using a plate specimen of commercial pure titanium on a digital holographic microscope stage. Microscopic deformation of the grains was observed, and their height distribution was measured on the specimen surface. Each grain showed nanoscopic movement up and down, as well as reverse movement corresponding to specimen loading and unloading. We suggest that the different grain-specific changes in height were caused by microscopic inhomogeneities in the material, such as differences in the crystal orientation and geometries of both the surface and subsurface grains. Changes in grain height increased with tensile load, and a strong relationship was found between the height changes that occurred under elastic and plastic conditions. This suggests that microscopic plastic deformation is predictable from microscopic elastic deformation. In order to investigate the plastic deformation of grains in more detail, slip-line angles were measured after the tensile test. We found slip lines with similar angles in neighboring grains, suggesting that the plastic deformation of grains was not independent, but rather was related to that of surrounding grains and influenced by the deformation of subsurface grains.

DOI： 10.3390/app8101907

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Dimensional Changes of Graphite Flakes and Fracture in Tensile Tests of Gray Cast Iron Reviewed

Naoya Tada, Takeshi Uemori

Conference papers, ASME 2018 Pressure Vessels & Piping Conference PVP2018-85214 2018

Effect of Contact Pressure Applied on Tool Surface during Cold Forging on Fatigue Life of Tool Steel Reviewed

Nuwan Karunathilaka, Naoya Tada, Takeshi Uemori, Ryota Hanamitsu, Masahiro Kawano

Procedia Manufacturing 15 488 - 495 2018

Cyclic Stress Strain Resposes of AZ31 Magnesium Alloy Sheet Metal at Elevated Temperature Reviewed

Takeshi Uemori, Takashi Katahira, Tetsuo Naka, Naoya Tada, Fusahito Yoshida

Procedia Manufacturing 15 1792 - 1799 2018

Elastic and Plastic Microscopic Undulation on the Surface of Polycrystalline Pure Titanium under Tension Reviewed

Naoya Tada, Takeshi Uemori, Toshiya Nakata

Transactions of the ASME, Journal of Pressure Vessel Technology 139 ( 6 ) 061403 2017.12

Evaluation of Thin Copper Wire and Lead-Free Solder Joint Strength by Pullout Tests and Wire Surface Observation Reviewed

Naoya Tada, Takuhiro Tanaka, Takeshi Uemori, Toshiya Nakata

Crystals 7 ( 8 ) 255 - 255 2017.8

Springback analysis of aluminum alloy sheet metals by yoshida-uemori model Reviewed

Takeshi Uemori, Kento Fujii, Toshiya Nakata, Shinobu Narita, Naoya Tada, Tetsuo Naka, Fusahito Yoshida

Key Engineering Materials 725 566 - 571 2017

Time-Dependent Fracture of Copper-Cored Lead-Free Solder Ball and Nickel Rod Joints in Air, Distilled Water, and NaCl Solution Reviewed

Naoya Tada, Takeshi Uemori

IMPACT 2017 Proceedings 319 - 322 2017

Tensile Test of Copper-Cored Lead-Free Solder Joints Using Non-Contact Type Testing Device with Permanent Magnets Reviewed

N. Tada, T. Uemori, T. Nakata

SEM Annual 2017 Proceedings 478 - 478 2017

Theoretical predictions of fracture and springback for high tensile strength steel sheets under stretch bending Reviewed

Takeshi Uemori, Tetsuo Naka, Naoya Tada, Hidenori Yoshimura, Takashi Katahira, Fusahito Yoshida

Procedia Engineering 207 1594 - 1598 2017

Microscopic Height Change on the Surface of Polycrystalline Pure Titanium Plate Under Cyclic Tension Reviewed

Naoya Tada

INTERNATIONAL DIGITAL IMAGING CORRELATION SOCIETY 267 - 271 2017

Cracking behavior of thin gold strip deposited on polycarbonate plate under Cyclic and stepwisely-increased tension Reviewed

Naoya Tada, Yafei Hu, Takeshi Uemori, Toshiya Nakata

2017 INTERNATIONAL CONFERENCE ON MECHANICAL, AERONAUTICAL AND AUTOMOTIVE ENGINEERING (ICMAA 2017) 108 01004 2017

Evaluation of bonding strength of thin copper wire and lead-free solder by pullout tests Reviewed

Naoya Tada, Takuhiro Tanaka, Hirotsugu Tabata, Takeshi Uemori, Toshiya Nakata

Proceedings of Technical Papers - International Microsystems, Packaging, Assembly, and Circuits Technology Conference, IMPACT 164 - 167 2016.12

Elastic and plastic microscopic deformation of polycrystalline pure titanium under tension Reviewed

Naoya Tada, Yuki Doi

American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP 3 PVP2016-63268 2016

Microscopic deformation of polycrystalline pure copper wire during tension Reviewed

Naoya Tada, Yoshitaka Matsukawa, Takeshi Uemori, Toshiya Nakata

2015 10th International Microsystems, Packaging, Assembly and Circuits Technology Conference, IMPACT 2015 - Proceedings 229 - 232 2015.12

Computational simulation of micro- to macroscopic deformation behavior of cavitated rubber blended amorphous polymer using second-order homogenization method Reviewed

Makoto Uchida, Naoya Tada

Key Engineering Materials 626 74 - 80 2015

FINITE ELEMENT ANALYSIS FOR THE EVALUATION OF CRACKS AT A PIPE-FLANGE WELDED PART BY THE DIRECT-CURRENT POTENTIAL DIFFERENCE METHOD Reviewed

Naoya Tada, Masaki Kosaka

PROCEEDINGS OF THE ASME PRESSURE VESSELS AND PIPING CONFERENCE - 2015, VOL 5 PVP2015-45484 2015

Surface Undulation of Pure Titanium Grains under Elastic and Plastic Tensile Conditions Reviewed

Naoya Tada

Extended Abstracts of 10th International Conference on Advances in Experimental Mechanics 2015

Deformation of vehicle body in pole side impact and its experimental modeling by means of rectangular steel tube

ONO Tadanori, SHIMIZU Ichiro, TADA Naoya, TAKUBO Nobuaki

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A 81 ( 826 ) 14 - 00542-14-00542 2015

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

Pole side impact is one of the most common types of vehicle collisions. The pole side impact at high vehicle speed induces not only local collapse but also bending of the vehicle body. However, the estimation method of the vehicle speed with consideration of the bending has not been established yet. In the present study, the deformation of the vehicle body at the pole side impact experiment with impact speed of 80 km/h was investigated. The results revealed that the collapse deformation first occurred and then the bending deformation followed. In order to understand the deformation of the vehicle at high-speed pole side impact, lateral local compression test and three-point bending test of rectangular steel tubes were performed. It was found that the deformation of the tube was similar to that of the vehicle at the pole side impact experiment, when the specimen was subjected to the sequential test of lateral local compression and three-point bending. The change in the energy absorbed by the deformation of tube in the sequential test was also found to be similar to that in the vehicle experiment. These similarities are useful to investigate the vehicle collision speed at high-speed pole side impact based on the deformation and the absorbed energy of rectangular metal tubes.

DOI： 10.1299/transjsme.14-00542

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POTENTIAL DIFFERENCE DISTRIBUTION ON FLAT PLATE AROUND SEMI-ELLIPSOIDAL THINNING ON THE BACK SURFACE

Naoya Tada, Makoto Uchida, Manabu Nohara

ASME PRESSURE VESSELS AND PIPING CONFERENCE - 2014, VOL 5 PVP2014-28684 2014

Evaluation of Tensile Strength of Copper-Cored Lead-Free Solder Joints in Air, Distilled Water, and NaCl Solution Using Testing Device with Permanent Magnets

Naoya Tada, Hiroyasu Masago

IMPACT-EMAP 2014 Proceedings 237 - 240 2014

NON-DESTRUCTIVE DETECTION OF CRACK IN HDPE PLATE BY NANOMETRIC CHANGE IN SURFACE PROFILE

Naoya Tada, Makoto Uchida, Yoshitaka Matsukawa

PROCEEDINGS OF THE ASME PRESSURE VESSELS AND PIPING CONFERENCE - 2013, VOL 5 PVP2013-97732 2014

Micro-, meso- to macroscopic modeling of deformation behavior of semi-crystalline polymer Reviewed

Makoto Uchida, Naoya Tada

INTERNATIONAL JOURNAL OF PLASTICITY 49 164 - 184 2013.10

Remotely-Controlled Tensile Test of Copper-Cored Lead-Free Solder Joint in Liquid Using Permanent Magnet

Naoya Tada, Hiroyasu Masago

IMPACT-IAAC 2013 Proceedings 372 - 375 2013

Investigation of Deformation Mechanism under Indentation Testing of Metastable Beta-type Reviewed

Ichiro SHIMIZU, Noriaki KIMURA, Naoya TADA, Yoshito TAKEMOTO

Proceedings of the 8th International Symposium on Advanced Science and Technology in Experimental Mechanics ( 62 ) 2013

Deformation Behavior of Multi-Layered Ceramic Capacitors Block under Non-Frame Press

NARUSE Fumio, TADA Naoya

Transactions of the Japan Society of Mechanical Engineers Series B 79 ( 800 ) 442 - 454 2013

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

To investigate the deformation behavior of multi-layered ceramic capacitors (MLCCs) during production press process is very important to reduce over all MLCC size and increase the capacity of the MLCC through the enlargement of the electrode area. In the previous paper, the deformation of MLCC blocks in the uniaxial compression test was observed and the filling mechanism was clarified based on the measurement results. In this study, the non-frame press tests of MLCC blocks were carried out to realize the high precision press, in which the lateral compressive stress was given in addition to the longitudinal one. The deformation process was clarified based on the results of cross-sectional observation. In the edge part of the MLCC block, the interlayer space in Side-Gaps L and W was decreased by longitudinal strain and the lateral strain, whereas, at the central part of the MLCC block, the interlayer space in Side-Gaps L and W was decreased only by longitudinal strain. Since the difference in the deformation behavior between the central part and the edge part generated variations in the thickness of MLCC block, the width of the internal electrode part and the width of the Side-Gap, it was concluded that non-frame press was not suitable for high precision press of MLCC block.

DOI： 10.1299/kikaia.79.442

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Establishment of Deformation Simulation Procedure by Finite Element Method Based on Second-Order Homogenization Using Characteristic Displacement Function for Macroscopic Strain Gradient

UCHIDA Makoto, TADA Naoya

Transactions of the Japan Society of Mechanical Engineers Series B 79 ( 806 ) 1486 - 1503 2013

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

To evaluate effect of a relative scale of microstructure to macrostructure, a simulation procedure using second-order homogenization based finite element method was proposed. In this method, a microscopic characteristic displacement function for macroscopic strain gradient was added to the conventional first order homogenization method. Then, a procedure to solve a macroscopic boundary problem was established based on the principle of virtual work in macroscopic scale represented by the microscopic characteristic displacement function. To validate the proposed second-order homogenization method, computational simulations of deformation behavior of cavitated rubber (void) blended amorphous polymer were performed using the proposed second-order homogenization. From the result of bending deformation where tension or compression was given to upper side or lower side of the macroscopic model, the material containing larger void required a larger energy for the bending of the model. With decrease in the void size, the energy converged to that predicted by first-order homogenization method. Basically, the deformation behavior predicted by proposed homogenization model was qualitatively and quantitatively similar to that predicted by full scale model. The proposed model is expected to be applied for computational prediction of the scale-dependent deformation in various cases because the model does not limit the form of constitutive equation, shape of the unit cell and deformation mechanisms and structure of the material.

DOI： 10.1299/kikaia.79.1486

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Microscopic Evaluation of Plastic Deformation during Back-and-Forth Bending of Polycrystalline Pure Titanium Specimen with a Pair of Parallel Grooves Using Arranged Marks at Lattice Points

TADA Naoya, SHIMIZU Ichiro

Transactions of the Japan Society of Mechanical Engineers Series B 79 ( 800 ) 420 - 432 2013

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

A single-cycle bending test of polycrystalline pure titanium was carried out using a rectangular specimen with a pair of parallel grooves. The plastic deformation in a long part between these grooves was observed at every quarter cycle of back-and-forth bending. Before the test, multiple square marks of gold were made at the lattice points having a mutual distance of 12.5 μm in the region of interest by ion-coater. The strain and rotation during the test were evaluated based on the displacement of these gold marks. The following results were obtained: (1) The region of interest between grooves showed plastic deformation during bending, and the deformation was mainly caused by slips. Twining was also observed in some grains. (2) The strain and rotation during the bending were not uniform grains to grains. The shearing strain was small compared with the normal strains and rotation. (3) The region, which showed a larger normal strain at the first quarter cycle, continued to show a relatively large strain at the following quarter cycles in an opposite direction. Rotation showed a similar behavior. (4) Crystal orientation analysis was performed for grains with clear slip lines. The plastic deformation of these grains seemed to occur mainly by the prismatic slip.

DOI： 10.1299/kikaia.79.420

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Evaluation of Strength of Diesel Engine Cylinder Block by Finite Element Analysis Based on Microstructure of Gray Cast Iron

IGUCHI Katsuyuki, TADA Naoya, SHIMIZU Ichiro

Transactions of the Japan Society of Mechanical Engineers Series B 79 ( 799 ) 281 - 293 2013

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

Stress distribution of gray cast iron was analyzed by the finite element analysis based on the actual distribution of graphite flakes embedded in pearlite. Three types of two-dimensional FE-models were used: (1) "true model" where graphite flakes were distributed in pearlite as observed, (2) "voids model" where graphite flakes were replaced by voids of the same geometries, and (3) "single void model" where one of selected voids which showed higher stress in the vicinity of void tip in the pearlite. As the voids model showed higher stress in the vicinity of each void tip, it was concluded that the voids model was appropriate for the safe-side evaluation of gray cast iron strength. Furthermore, a simplified method of strength evaluation was proposed by comparing the results of the voids model with those of the single void model. Since the maximum ratio of the stress near the void tip was 6.27 between the voids model and the single void model, tensile and fatigue strengths of gray cast iron was evaluated by the stress intensity factor multiplied by 6.27 using the maximum length of graphite flakes, the threshold stress intensity factor range and fracture toughness of pearlite about the tested diesel engine cylinder block. The method validated the safety of cylinder block of the tested diesel engine.

DOI： 10.1299/kikaia.79.281

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Study on Deformation of Rectangular Metal Tube during Dynamic Three-Point Bending for Modeling of Pole Side Impact of Vehicle

Tadanori Ono, Ichiro Shimizu, Naoya Tada, Nobuaki Takubo

Proceedings of Joint International Conference of the 2nd International Symposium on Experimental Mechanics, The 11th Asian Conference on Experimental Mechanics and 2012 Society for Experimental Mechanics Fall Conference, 7th International Symposium on ・・・ No.A122 2012

625 Compressive Forming Limit of Cast AZ31 Magnesium Alloy during Nonproportional Strain Paths

AKIYAMA Daisuke, SHIMIZU Ichiro, HIRANO Seiki, TADA Naoya

61 No.0110 - 382 2012

Tensile Test of Small Lead-Free Solder Joint Using Permanent Magnet Reviewed

Naoya Tada, Ryo Nishihara, Hiroyasu Masago

2012 7TH INTERNATIONAL MICROSYSTEMS, PACKAGING, ASSEMBLY AND CIRCUITS TECHNOLOGY CONFERENCE (IMPACT) 346 - 349 2012

NON-DESTRUCTIVE CRACK DETECTION BY NANOMETRIC CHANGE IN SURFACE PROFILE USING DIGITAL HOLOGRAPHIC MICROSCOPE Reviewed

Naoya Tada, Makoto Uchida, Yuki Uenoyama

PROCEEDINGS OF THE ASME PRESSURE VESSELS AND PIPING CONFERENCE, PVP 2012, VOL 5 251 - 257 2012

Effect of Spherulite Size on Macroscopically Non-Uniform Deformation of Semi-Crystalline Polymer Reviewed

Makoto Uchida, Naoya Tada

Proceedings of PLASTICITY '12: The Eighteenth International Symposium on Plasticity and Its Current Applications 316 - 318 2012

Computational Simulation of Polymer RVE Model under Boundary Condition with Macroscopic Strain Gradient Reviewed

M. Uchida, N. TADA

Proceedings of 4th International Conference on Computational Methods ID197 2012

Sequential evaluation of continuous deformation field of semi-crystalline polymers during tensile deformation accompanied by neck propagation Reviewed

Makoto Uchida, Naoya Tada

INTERNATIONAL JOURNAL OF PLASTICITY 27 ( 12 ) 2085 - 2102 2011.12

Development of Press Machine by Means of Reverse-type Differential Rotary to Linear Conversion Mechanism Reviewed

SHIMIZU Ichiro, SEKI Masanori, MATSUI Takafumi, TADA Naoya, FUJII Masahiro, YOSHIDA Akira

Journal of Japan Society for Design Engineering 46 ( 1 ) 40 - 47 2011.1

解説直流電位差法を用いた配管内外表面き裂と肉厚評価の最新技術 Reviewed

多田直哉

検査技術 16 ( 5 ) 21 - 28 2011

Influence of Plastic Anisotropy on Compressive Forming Limit of AZ31 Magnesium Alloy

Ichiro SHIMIZU, Kosuke Okada, Seiki Hirano, Naoya TADA

Proceedings of International Symposium on Advanced Science and Technology in Experimental Mechanics (6th ISEM '11-Sendai/Kansai) 121 2011

OS09-4-2 Experimental Modeling of Vehicle Deformation in Pole Side Impact by Means of Lateral Compression of Rectangular Steel Tube

ONO Tadanori, SHIMIZU Ichiro, TADA Naoya, TAKUBO Nobuaki

Abstracts of ATEM : International Conference on Advanced Technology in Experimental Mechanics : Asian Conference on Experimental Mechanics 2011 ( 10 ) OS09-4-2 - 4-2-1" 2011

Deformation Behavior of Multilayered Ceramic Sheets with Printed Electrodes under Compression

NARUSE Fumio, TADA Naoya

Journal of Solid Mechanics and Materials Engineering 6 ( 6 ) OS18F003 - 770 2011

Language：English Publisher：The Japan Society of Mechanical Engineers

Deformation behavior of multi-layered ceramic capacitors (MLCCs) during production press process is very important to reduce over all MLCC size and increase the capacity of the MLCC through the enlargement of the electrode area. In this study, compression tests of MLCC blocks, which were composed of stacked ceramic dielectric sheets and printed internal electrodes, were carried out, and the deformation process was clarified based on the results of cross-sectional observation. Deformation of MLCC block was modeled and predicted using the area fraction of dielectric sheets, internal electrodes, and internal space. The prediction agreed well with the experimental results and helps the optimization of MLCC design.

DOI： 10.1299/jmmp.6.760

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Effect of Distribution of Spherulite on the Non-Uniform Plastic Deformation Behaviour of Semi-Crystalline Polymer

M. Uchida, N. Tada

Computational Plasticity XI, Fundamentals and Applications (COMPLAS XI) 2011

Detection of stress corrosion cracking by direct-current potential difference method Reviewed

Naoya Tada, Makoto Uchida, Hiroki Maeda, Atsushi Hozuki

American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP 5 217 - 224 2011

A method of crack detection in the turbine blade using digital holographic microscopy (DHM) Reviewed

Naoya Tada, Seiichi Hamada, Tetsuo Teramae, Shin Yoshino, Takehiko Suzuki

American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP 5 211 - 216 2011

解説デジタルホログラフィック顕微鏡を用いた材料表面特性評価 Reviewed

多田直哉, 内田真

非破壊検査 60 ( 10 ) 592 - 598 2011

解説直流電位差計測に基づくき裂評価手法の展開

武尾文雄, 多田直哉

非破壊検査 60 ( 10 ) 572 - 578 2011

Modeling of Micro- to Mesoscopic Deformation Behavior of Semi-Crystalline Polymer Based on Laminar Composite Model

UCHIDA Makoto, TADA Naoya, TOMITA Yoshihiro

Transactions of the Japan Society of Mechanical Engineers Series B 77 ( 778 ) 902 - 915 2011

Publisher：The Japan Society of Mechanical Engineers

Since semi-crystalline polymer has very complex hierarchical structure, it is essential to construct a suitable multiscale mechanical model for the prediction of its mechanical characteristics. For the establishment of the triple scale mechanical model of semi-crystalline polymer, which can reflect the non-uniform deformations in micro-, meso- and macroscopic scales, computationally efficient model to relate structures and deformations in micro- to mesoscopic scales is indispensable. In this paper, to solve the problems, tangent modulus method was introduced into the constitutive equations for crystalline and amorphous phases consisting of the microstructure of semi-crystalline polymer. Furthermore, we proposed a new laminar composite model connecting deformations in micro- to mesoscopic scales based on the equilibrium of stress acting on the interface between the phases and the compatibility of deformation along the interface. Appropriate time steps for stable simulation and validity of the proposed model were examined through the computational simulation of uniaxial tension of single lamellar and spherulite models of high density polyethylene. It has been clarified that the proposed model could predict an elasto-viscoplastic deformation behavior of semi-crystalline polymer in markedly less computational time and memory.

DOI： 10.1299/kikaia.77.902

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Finite element simulation of deformation behavior of semi-crystalline polymers with multi-spherulitic mesostructure Reviewed

Makoto Uchida, Tsuruyo Tokuda, Naoya Tada

INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES 52 ( 2 ) 158 - 167 2010.2

A Study on the Fatigue Life Evaluation of Vibration Insulator Considering the Effect of Creep Reviewed

Prabhakar Soma, Naoya Tada, Makoto Uchida, Kazunari Nakahara, Tetsuya Miyake

Conference Proceeding (Programme and Abstracts), International Rubber Conference & Exhibition 2010 426 - 429 2010

Influence of Initial Texture on Plastic Behavior of Pure Titanium in Biaxial Compression Reviewed

Ichiro SHIMIZU, Junya IDEI, Naoya TADA

Proceedings of the 5th International Symposium on Advanced Science and Technology in Experimental Mechanics 2010

POTENTIAL DIFFERENCE AROUND SEMI-ELLIPTICAL CRACK ON THE OUTER SURFACE OF PIPE FOR NON-DESTRUCTIVE EVALUATION OF CRACK BY DC-PDM Reviewed

Naoya Tada, Makoto Uchida, Hiroki Maeda

PROCEEDINGS OF THE ASME PRESSURE VESSELS AND PIPING CONFERENCE 2010, VOL 5 215 - 222 2010

Plastic behaviour and forming limit during biaxial compressions of magnesium alloy AZ31 at room temperature

I. Shimizu, N. Tada

ICEM 14: 14TH INTERNATIONAL CONFERENCE ON EXPERIMENTAL MECHANICS, VOL 6 6 16001-1-16001-2 2010

The Effect of Heterogeneity of Microstructure on the Micro- to Macroscopic Non-Uniform Elasto-Viscoplastic Deformation Behavior of Polymeric Material

Makoto Uchida, Naoya Tada

Proceedings of PLASTICITY '10: The Sixteenth International Symposium on Plasticity and Its Current Applications 298 - 300 2010

Evaluation of orientation-dependent geometry of micro triangular indentation on grain of polycrystalline alpha-titanium

I. Shimizu, N. Tada, T. Ishida

FOURTH INTERNATIONAL CONFERENCE ON EXPERIMENTAL MECHANICS 7522 60 - 60 2010

NUMERICAL SIMULATION FOR IDENTIFICATION OF SEMI-ELLIPTICAL CRACK ON THE INNER SURFACE OF PIPE BY MEANS OF DIRECT-CURRENT ELECTRICAL POTENTIAL DIFFERENCE METHOD WITH MULTIPLE-PROBE SENSOR Reviewed

Naoya Tada, Makoto Uchida, Hiroki Ishikawa

PROCEEDINGS OF THE ASME PRESSURE VESSELS AND PIPING CONFERENCE 2009, VOL 5 257 - 263 2010

解説高温における材料寿命予測法

多田直哉

検査技術 15 ( 10 ) 23 - 29 2010

解説直流電位差法を用いたき裂評価技術の現状 Reviewed

多田直哉, 浜田晴一

非破壊検査 59 ( 5 ) 204 - 208 2010

A Fracture Mechanics Approach for Evaluating the Effects of Heat Aging on Fatigue Crack Growth of Vulcanized Natural Rubber Reviewed

Prabhakar Soma, Naoya Tada, Makoto Uchida, Kazunari Nakahara, Yoshifumi Taga

Proc. of the Asian Pacific Conference for Materials and Mechanics 2009, The Japanese Society of Mechanical Engineers a138 2009

Research and Education in the Field of Applied Solid Mechanics Reviewed

Naoya Tada

Proc. 2009 International Symposium on Total Engineering Education, East China University of Science and Technology 167 - 174 2009

Regional Identification by Digital Height Correlation of Nanolevel Surface Profile

N.Tada, N.Yagi, I.Shimizu, M.Uchida

Final Program and Abstracts, SEM 2009 Fall Symposium and Workshop, Advanced Image-Based Measurement Methods: Recent Developments and Applications in Engineering and Medicine, The Society for Experimental Mechanics, Inc. 15 - 15 2009

Electric Field Analysis of Simultaneous Evaluation of Crack on Inner Surface of Pipe and Pipe Wall Thickness Using Direct-Current Potential Difference Method of Multiple-Probe Type Reviewed

Naoya Tada, Makoto Uchida

Abstract book the 12th International Conference on Pressure Vessel Technology, Korean Society of Pressure Vessels & Piping 563 - 570 2009

Evaluation of geometry of semi-elliptical crack by direct current potential difference method based on potential difference distribution in two orthogonal directions

Makoto Uchida, Hiroki Ishikawa, Naoya Tada

Conference Handbook of the 13th Asia-Pacific Conference on NDT, 2009 248 248 - 248 2009

APPLICATION OF DIRECT-CURRENT POTENTIAL DIFFERENCE METHOD TO EVALUATION OF VARIOUS DAMAGES IN CONDUCTIVE MATERIALS Reviewed

Naoya Tada

PROCEEDINGS OF THE ASME PRESSURE VESSELS AND PIPING CONFERENCE, VOL 5 183 - 189 2009

Numerical Study on Reducing Methods of Static Strain along the Fillet on Upper Deck of Diesel Engine Cylinder Block Reviewed

Katsuyuki Iguchi, Naoya Tada, Ichiro Shimizu, Kouji Iwasaki

Proc. the 12th International Conference on Fracture 2009

Finite Element Analysis of Static Strain along the Fillet on Upper Deck of Diesel Engine Cylinder Block Produced by Tightening of Cylinder Head Bolts

IGUCHI Katsuyuki, TADA Naoya, SHIMIZU Ichiro

Transactions of the Japan Society of Mechanical Engineers Series B 74 ( 744 ) 1053 - 1059 2008.8

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

The distribution of static strain along the fillet on an upper deck of cylinder block and its dependency on the depth of thread engagement for cylinder head bolts were evaluated for a diesel engine by the finite element method. Since the fillet on upper deck is one of the critical parts in the cylinder block that may be cracked by stress and strain concentration, the static strain along the fillet was focused on in this study. In the model, the static tightening force of cylinder head bolts balanced with the total force acting on the cylinder block. A uniform surface pressure calculated by the total force divided by the contact area was given to the upper deck. The following results were obtained.<BR>The static strain along the fillet was dependent on the circumferential direction of cylinder and its value was varied with the depth of thread engagement for cylinder head bolts. The optimum depth of thread engagement was determined to be about 100 mm from the viewpoints of the overall magnitude of strain, the circumferential fluctuation of strain, the change rate of strain against the depth of thread engagement, and the length of cylinder head bolt. The calculated circumferential distribution of the static strain and the tightening force were compared with the measurement results under the optimum depth of thread engagement condition. Both results agreed well and this fact suggests that the present analysis is useful for optimizing the structural design of cylinder block for diesel engines.

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Papers - TADA Naoya