Faculty Profiles - TADA Naoya

MISC - TADA Naoya

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111 Investigation of Corrosion Resistance of A2024 Aluminum and AZ31 Magnesium Alloys with KURACERA and Sealing Treatments

MORIFUJI Syun, TADA Naoya, MAKINO Yukinobu, SAKODA Nobuaki, SAKO Sayaka

2015 ( 53 ) "111 - 1"-"111-2" 2015.2

Polycrystalline finite element analysis of crystal orientation effect on surface roughness of pure titanium sheet

KAKIHARA Hiroki, UEMORI Takeshi, TADA Naoya

( 155-1 ) 117 2015.2

Engineering Collaboration in Applied Solid Mechanics

Naoya Tada

Proceedings of the 3rd International Symposium on Total Engineering Education 45 - 46 2015

Report on the 65th Japanese Joint Conference for the Technology of Plasticity

TADA Naoya

Journal of the JSTP 56 ( 649 ) 129 - 130 2015

G0310201 Compressive Plastic Deformation in Micro Areas between Parallel Grooves and in V-shaped Cross-Section Groove Fabricated on Polycrystalline Pure Titanium Surface

SHIMIZU Ichiro, ISOKAWA Katsuhiro, HARA Kousuke, TADA Naoya

Mechanical Engineering Congress, Japan 2014 "G0310201 - 1"-"G0310201-3" 2014.9

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

The compressive deformation behavior in micro areas of industrial pure titanium was investigated, by using a new method in which the deformation constraints from the neighboring areas were reduced by fabricating micro parallel grooves or V-shaped cross-section grooves, by focused ion beam machining. Uniaxial compression test was performed in the direction parallel to the grooves, and the deformation behavior in the areas between the grooves was observed by scanning electron microscopy. The parallel grooves were fabricated to across the deformation twin that appeared by pre-compression, and then the influence of deformation constraint on twinning was discussed. Meanwhile, the V-shaped cross-section grooves were fabricated on several grains to examine the crystal orientation dependency of the deformation of the micro areas. In both cases, the possibility was found to change the primary deformation mechanism in the areas by fabricating micro grooves.

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OS0118 Alloy Composition Dependency of Equi-Plastic Work Surfaces in Biaxial Compressions of Ti-Nb Alloys

SHIMIZU Ichiro, HISADA Kazuki, ISHIKAWA Shinichi, TADA Naoya

2014 "OS0118 - 1"-"OS0118-2" 2014.7

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

Metastable beta type titanium alloys have been attracting attention in various industrial fields because of their special properties such as high specific strength, good formability, high corrosion resistance, and biocompatibility. However, plastic deformation characteristics of the titanium alloys have scarcely been clarified especially under biaxial loading conditions, despite of their importance on metal forming processes. In the present study, uniaxial and biaxial compression tests were performed on titanium-niobium (Ti-Nb) alloys with four different niobium contents, in order to investigate the influences of beta stabilizer content upon compressive deformations. The microstructure of Ti-Nb alloys was found to change from α, α' to p structure with increase of the niobium content. With this change of microstructure, the primary plastic deformation mechanisms were revealed to change from slip and stress-induced martensite to deformation twin and coarse slip with increase of the niobium content and thus the change influenced on the uniaxial and biaxial compressive plastic behaviors.

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115 Deformation Analysis during Production Press Process of Laminated Electronic Component Using Finite Element Method

YAMAJI Ken, TADA Naoya, NARUSE Fumio, YAHIRO Toshiaki

2014 ( 52 ) "115 - 1"-"115-2" 2014

114 Evaluation of Absorbed Energy during Lateral Local Compression and Three-Point Bending of Aluminum Alloy Rectangular Tube by Finite Element Method

ITO Masashi, ONO Tadanori, SHIMIZU Ichiro, TADA Naoya

2014 ( 52 ) "114 - 1"-"114-2" 2014

113 Joint Strength Evaluation of Copper-Cored Lead-Free Solder Ball in Air, Pure Water and 3.5 wt.% NaCl Solution by Testing Device Using Permanent Magnet

MASAGO Hiroyasu, TADA Naoya

2014 ( 52 ) "113 - 1"-"113-2" 2014

1419 Micro-, mezo- to macroscopic modeling of elasto-viscoplastic deformation of polypropylene

UCHEDA Makoto, TADA Naoya

The Computational Mechanics Conference 2013 ( 26 ) "1419 - 1"-"1419-2" 2013.11

OS0402 Comparison between Plastic Deformation Behaviors under Equi-Biaxial Compression and Uniaxial Tension of AZ31 Magnesium Alloy

SHIMIZU Ichiro, NISHIZAKI Seiki, TADA Naoya

2013 "OS0402 - 1"-"OS0402-3" 2013.10

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

Tension-compression asymmetry of plastic deformation of magnesium alloys has been known to affect plastic formability in several metal forming processes. However, in most of works on the tension-compression asymmetry, the result of uniaxial tension was compared with that of uniaxial compression. In the present study, the plastic deformation behavior of AZ31 magnesium alloys in uniaxial tension was investigated and compared with those in equi-biaxial compression, in which the macroscopic deformation was equivalent to that of uniaxial tension. It was found that the equi-plastic work point obtained by equi-biaxial compression was on the same isotropic yield curve with that by uniaxial tension, in the early stage of plastic deformation. The crystal orientation measurement results also revealed that the twin area fractions as well as active twin systems by uniaxial tension were almost the same with those by equi-biaxial compression. These results imply that the difference between deformation patterns by uniaxial tension and by uniaxial compression is primary cause of the tension-compression asymmetry of magnesium alloys.

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OS0408 Nanometric Change in Surface Height and Microscopic Elasto-Plastic Deformation in Tension of Pure Titanium

TADA Naoya, UCHIDA Makoto, YAGI Nobuaki

2013 "OS0408 - 1"-"OS0408-3" 2013.10

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

A tensile test of pure titanium plate specimen was performed on the stage of digital holographic microscope, and a change in the height of each grain on the surface was evaluated during the tests. The load was increased stepwise in the tensile test and the distribution of height change of each grain was evaluated at all steps in nanometer order. The identification of region before and after each loading step was done by the Digital Height Correlation Method (DHCM). The height change of each grain between low loading levels corresponded to that between relatively high loading levels, which suggests that the height change in plastic deformation occurred mainly by crystallographic slips can be predicted by that in elastic deformation. Slip lines after the plastic deformation were observed and the correlation of the slip lines and height change of the grain was discussed.

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G031031 Direct-Current Electric Potential Field Analysis of Plate with Local Wall Thinning of Semi-Ellipsoidal Shape

NOHARA Manabu, TADA Naoya, UCHIDA Makoto

Mechanical Engineering Congress, Japan 2013 "G031031 - 1"-"G031031-4" 2013.9

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

The direct-current potential difference method (DC-PDM) is an inspection technique to evaluate defects in structures. Although the method needs large direct current and relatively large equipment, many studies on the applicability of DC-PDM to non-destructive inspection have been performed because of low cost, cheap, and good reproducibility of results. DC-PDM has been applied to evaluate general wall thinning. But very few papers deal with the application of DC-PDM to local wall thinning. In this study, approximated solution for electric potential field analysis of a semi-ellipsoidal wall thinning existing on the back surface of a conductive plate was proposed and its validity was examined by comparing with the results by finite element method. The approximated solution agreed with the finite element analysis.

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G031014 Study on Relationship between Microscopic Change in Surface Height and Slip Line Distribution in Pure Titanium during Tension Using Digital Holographic Microscope

YAMAMOTO Yudai, TADA Naoya, UCHIDA Makoto

Mechanical Engineering Congress, Japan 2013 "G031014 - 1"-"G031014-5" 2013.9

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

Polycrystalline metals are composed of grains with different crystal orientations and sizes, and show inhomogeneous elastic-plastic deformation behavior. Especially for grains on the surface, the inhomogeneous deformation appears accompanied by the change in the height distribution. On the other hand, recently, digital holographic microscope is used to measure the height distribution on the materials surface with high accuracy in a short time. In this study, a cyclic tensile test of polycrystalline pure titanium was carried out and the change in the height distribution was studied using the digital height correlation method. Increase in average height of each grain by unit load in elastic region correlated with those in plastic region, which suggests that the plastic deformation is predictable from the elastic deformation.

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G031022 Observation of Compressive Deformation inside Pure Titanium Grain with Reduced Deformation Constraint by Parallel Grooves

ISOKAWA Katsuhiro, SHIMIZU Ichiro, TADA Naoya

Mechanical Engineering Congress, Japan 2013 "G031022 - 1"-"G031022-4" 2013.9

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

In the present study, a new method to reduce deformation constraint in a grain of industrial polycrystalline pure titanium was introduced, by fabricating micro parallel grooves in the grain by means of a focused ion beam method. Uniaxial compression test was then performed in the direction parallel to the grooves, and the influence of reduced deformation constraint upon the characteristics of plastic deformation in the area between the grooves was investigated. The comparisons of the plastic deformation of the area with that without grooves revealed that the plastic deformation behavior as well as the deformed feature of the grain clearly changed by the presence and absence of the deformation constraint. The influence of deformation constraint upon the plastic deformation behavior of titanium grain was thus discussed with taking into consideration the crystallographic orientation.

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G031016 Influence of Alloy Composition upon Biaxial Compressive Deformation Behavior along Proportional Strain Path of Metastable p-Type Titanium-Niobium Alloys at Room Temperature

HISADA Kazuki, SHIMIZU Ichiro, TAKEMOTO Yoshito, TADA Naoya

Mechanical Engineering Congress, Japan 2013 "G031016 - 1"-"G031016-4" 2013.9

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

Metastable β-type titanium alloys have many features such as high specific strength, good ability of plastic deformation, excellent corrosion resistance, biocompatibility, and low Young's modulus, which are useful in aerospace, biomedical and chemical industries. However, plastic deformation behaviors of metastable β-type titanium alloys under multi-axial compressive conditions have not been clarified. In the present study, four types of Ti-Nb alloys, Ti-20mass%Nb, Ti-30mass%Nb, Ti-35mass%Nb, and Ti-45mass%Nb were prepared. The uniaxial and biaxial compression tests with proportional strain paths were then performed on Ti-Nb alloys by using a biaxial compression testing machine. The results of uniaxial compression tests revealed that stress induced martensite transformation, deformation twin, coarse slip occurred on Ti-20 and 30Nb, Ti-35Nb, and Ti-45Nb, respectively. It was found by biaxial compression tests that the plastic deformation behavior including anisotropic hardening also changes with Nb content.

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G011044 Finite Element Analysis on Evaluation of Crack Position and Size in Pipe-Flange Welded Part by Direct-Current Potential Difference Method

KOSAKA Masaki, TADA Naoya, UCHIDA Makoto

Mechanical Engineering Congress, Japan 2013 "G011044 - 1"-"G011044-4" 2013.9

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

Detection of cracks initiated at pipe-flange welded part by using direct current potential difference method had been proposed and the related researches have been conducted. However, the evaluation of the position and shape of the crack has not been discussed. In this study, three-dimensional electric potential field analysis was carried out by finite element method assuming that crack was initiated at the interface between flange and weld metal and effect of the circumferential angle and the central position of the crack on change in potential difference at the boundary between weld metal and flange was evaluated. As a result, potential difference along the circumferential direction significantly changed around the both tips of crack and the position where potential difference shows extreme value approximately corresponded to the crack tips.

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J042032 Study on Relationship between Area Fraction of Graphite and Inclination and Position of Tensile Fracture Surface of Gray Cast Iron

INADA Yusuke, TADA Naoya, SHIMIZU Ichiro, IGUCHI Katsuyuki

Mechanical Engineering Congress, Japan 2013 "J042032 - 1"-"J042032-3" 2013.9

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

Gray cast iron is used as structural materials for many machines. It has been assumed homogeneous when its strength was evaluated. But it has a composite structure of perlite and graphite. It is necessary to consider its microstructure for accurate strength evaluation of reliable products. In this study, the distribution of graphite was observed by SEM and its area ratio A_G was evaluated in equally divided areas of parallel part of specimen. It was found that high A_G region corresponded to the fracture surface of tensile test. This fact suggests that the position of fracture surface is predictable by the distribution of graphite.

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G031071 Deformation and Fracture of A5052 Aluminum Alloy Specimens with Hard Anodic Oxidation and KURACERA Treatments under Uniaxial Tension

MORIFUJI Syun, TADA Naoya, SHIMIZU Ichiro, MAKINO Yukinobu, SAKODA Nobuaki, TAJIRI Sayaka

Mechanical Engineering Congress, Japan 2013 "G031071 - 1"-"G031071-4" 2013.9

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

Recently, aluminum alloys are important structural materials because of high specific strength, lightweight, excellent in recycling. Various surface treatments for aluminum alloys have been developed for improvement of corrosion and wear resistances. Among them, environment-friendly anodizing in which oxide coating is formed on the material surface with easy process has been applied to a wide range of structural material. Also, plasma electrolytic oxidation (PEO) treatment was developed. Since KURACERA coating, it is classified PEO coating, is harder than anodic oxide coating, it is expected spacious application. In this study, in order to research the effect of oxide coating on deformation and fracture behavior, hard anodizing and KURACERA treated test specimen were observed with microscope during tensile test and the results were compared. The following results were obtained. With increasing the coating thickness, longitudinal elastic constant of coating, tensile strength and strain at fracture decreased. Longitudinal elastic constant of KURACERA coating was larger than that of hard anodic oxide coating. Also, since surface roughness was large in specimens with thick coating, more stress concentration occurred in thick coating larger and made necking and cracking easy.

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J012022 Finite Element Analysis on Evaluation of Crack on Joint Interface between Copper-Cored Lead-Free Solder Ball and Copper by DC-PDM

KAI Tomoki, TADA Naoya

Mechanical Engineering Congress, Japan 2013 "J012022 - 1"-"J012022-5" 2013.9

Language：Japanese Publisher：The Japan Society of Mechanical Engineers

In this study, Direct-Current Potential Difference Method (DC-PDM) was proposed for quantitative evaluation of crack initiation and propagation on joining between copper-cored lead-free solder ball and copper plate specimen when copper plate specimen was subjected to cyclic tension. Finite element method was used for three dimensional potential analysis to clarify the relationship between change in potential difference and change in crack depth. In addition, influence of crack depth and joint condition on potential difference was considered. It was found that the relationship between crack size and potential difference is represented by a master curve with modification coefficient of core independently of joint condition.

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