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Research Division of Materials Joining Assessment

Research Areas

Research Division of Materials Joining Assessment

Dept. of Joining Mechanics and Analyses

The department of joining mechanics and analyses is dedicated to solve structural manufacturing and application problems, in which various phenomena, i.e. heat sources, materials, processes, and mechanics, coupled in the welding, joining and additive manufacturing, are revealed by numerical simulation based on mathematical modeling and Artificial Intelligence. With the aid of AI enhanced research software JWRIAN and advanced measuring technology, safety and reliability of various structures manufactured by joining/welding are evaluated.

Current Research Subjects

1. Thermal-mechanical analysis of joining/welding stress/strain and fatigue life
2. Digital twin for Metals/CFRTP welding process
3. Analysis and measurement of stress/strain/strength of dissimilar welded joints
4. Thermal-mechanical analysis of additive manufacturing process and stress/strain/strength
5. Thermal-mechanics and materials fl ow analysis of friction-based solid-state welding processes
6. Particle method for dissimilar materials flow analysis in friction stir welding

Research Concept of Joining Mechanics and Analyses

(a)IGA for optimal shape design of welded joint in structures

(b)Digital twin for Metals/CFR TP resistance spot welding

(c)Miniature tests of weld and HAZ for strength analysis

(d)M-W model for thermal-mechanical analysis of AM process

(e)Euler-Lagrange Coupling for various friction stir welding

(f)Additive manufacturing induced residual stress

Members

Prof.

N. MA

S. A. Prof.

K. NAKAO

S. A. Assist. Prof.

W. Huang

S. A. Researcher

K. NARASAKI

Research Division of Materials Joining Assessment

Dept. of Joining Design and Structuring

In this research division, the structural design and fabrication processes are considered on the following two aspects: the "through-process" and "trans-scale." The concept of "through-process" considers the time axis throughout the life cycle, from the design and construction process, such as welding and joining, to testing, service, repair, reinforcement, and maintenance. The concept of "trans-scale" considers spatial axes ranging from micro to macro, such as the microstructure of materials of welds, welding and joining components, and structures.
We research the evaluation of the performance and reliability of various structures at each of these stages and scales. In particular, the effects of thermal processing, represented by residual stresses and deformations, on the performance of welded and joined components and structures will be clarified from both microscopic and macroscopic perspectives. We will also develop a detailed and intelligent evaluation method based on these findings. Our goal is to establish design engineering that contributes to the advancement of structuring processes such as welding and joining.

Current Research Subjects

1. Development of evaluation methods for strength properties and reliability of structural members, welds and joints
2. Development of performance evaluation technique for welded structures in consideration of residual stress
3. Development of manufacturing process simulation technology for design applications
4. Development of damage evaluation method considering microscopic plastic deformation behavior of materials and welds
5. Evaluation of cracking characteristics considering heterogeneity of structural materials and weld

Members

Prof.

Y. MIKAMI

Assist Prof.

H. ZHOU

Research Division of Materials Joining Assessment

Dept. of Joining Metallurgical Evaluation

Development of innovative manufacturing technology is required for high-performance mechanical products and structures for the next generation. Department of Joining Metallurgical Evaluation conducts research and education for explication and control of the factors on weldment properties to create innovative and attractive techniques of welding & joining as a final aim. Specifically, our department is working on clarification of the characteristics of spot welds of dissimilar materials and spot welds using resistance heat generation. We are also working on elucidation of metallurgical phenomena such as solidification and transformation during welding and additive manufacturing, and on developing the control method for the microstructures and the properties of weldments.

Current Research Subjects

1. Development of resistance spot welding technology for advanced sheet materials
2. Analysis of weld interface structure of dissimilar welded joints
3. Development of tailored dismantling technique of welds and joints
4. Improvement and prediction of weld cracking susceptibility by microstructural control
5. Development of evaluation method for solidification/transformation behavior and hot cracking susceptibility during welding and additive manufacturing
6. Elucidation of influential factors of corrosion resistance of welds

Evaluation and analysis of hot cracking susceptibility test


Observation of pitting initiation in heat-affected zone by FESEM
(a)α/γInterface and (b)α-ferrite, (c)Location of pitting initiation

Cross-sectional photo and IMC thickness distribution of weld interface of resistance spot weld of aluminum alloy sheet to high-strength steel sheet


Members

Prof.

R. IKEDA

Assoc. Prof.

K. KADOI

Research Overview

Research Areas

Research Division of Materials Joining Process

Dept. of Energy Control of Processing Dept. of Energy Transfer Dynamics Dept. of Micro Joining Dept. of Laser Materials Processing

Research Division of Materials Joining Mechanism

Dept. of Welding Mechanism Dept. of Joint Interface Structure and Formation Mechanism Dept. of Composite Materials Processing

Research Division of Materials Joining Assessment

Dept. of Joining Mechanics and Analyses Dept. of Joining Design and Structuring Dept. of Joining Metallurgical Evaluation

Research Center for Additive Joining Application (RAJA)

Dept. of Green Additive Manufacturing Dept. of Lithgraphic Additive Manufacturing Dept. of Additive Manufacturing Mechanism Dept. of Laser Additive Manufacturing Dept. of Advanced Additive Manufacturing

Strategy Office for Promotion of Inter-Institute Collaborations

Strategy Office for Promotion of Inter-Institute Collaborations

Joint Interface Microstructure Characterization Room

Joint Interface Microstructure Characterization Room

Global D&I Promotion Office

Global D&I Promotion Office

New Normal Manufacturing Consortium Office

New Normal Manufacturing Consortium Office

Research Alliance Laboratories

DAIHEN Welding and Joining Research Alliance Laboratories Nippon Steel Future Manufacturing Research Alliance Laboratories Honda-Osaka Univ. Joining Technology Monozukuri Research Alliance Laboratories

Joint Research Chair

Osaka Fuji Advanced Functional Processing Joint Research Chair

International and Industry-academia Joint Research Center

Global Collaborative Research Center for Computational Welding Science(CCWS) Joining Technology Hub Co-Creation Consortium for Joining and Welding with Blue Diode Laser
Our Researchers