Parameter estimation for spot-weld fracture prediction models using data assimilation

Risako Ito･Yoshiteru Ishibashi･Taichi Sato･Yasuhiro Tosaka (Nissan Motor)

Regarding fracture prediction of spot welds in FEM analysis, the current major method is based on load criteria. Recently, more detailed spot weld models have been proposed in order to reproduce the spot weld failure based on multiaxial stress state under combined loading on the heat-affected zone (HAZ), where fracture initiates. However, it is difficult to directly measure the material properties of the HAZ through experiments. In this study, data assimilation is applied to estimate the material properties of the HAZ.

Study on Crash Analysis Correlation of Aluminum Die Casting Components Using Simplified Casting Simulation

Kenichiro Fukagawa (Honda R&D)

In recent years, the application of aluminum die castings to automotive body structures has been expanding. Aluminum die castings exhibit material property distributions, and reflecting these distributions is important for achieving accurate crash analysis correlation. Prediction methods for such distributions include casting simulation; however, issue remain for application in the early stage of development. In this study, a method for predicting material property distributions using simplified casting simulation and applying the results to crash analysis, which can be implemented in the early stage of development, was investigated.

A Study on Fracture Analysis Using Isogeometric Analysis with Trimmed Solids

Shinnosuke Nishi･Tadashi Naito (Honda R&D)･Norio Shimizu (JSOL)

Isogeometric analysis with trimmed solids enables efficient modeling of complex geometries while maintaining high accuracy through high-order basis functions. In this study, we apply trimmed solids incorporating Lumped Assumed Strain elements to the fracture analysis of aluminum components under crash conditions. Comparative simulations using conventional FEM solid elements are conducted to assess differences in accuracy and computational cost. The results demonstrate the effectiveness of the proposed approach and provide insight into the underlying factors governing its effectiveness in fracture analysis.

Optimal Shape Design of Crash-Resistant Parts Using Linear Buckling Analysis

Ryo Ageba･Kazuhiko Higai･Toyohisa Shinmiya (JFE Steel)

To address increasing performance demands on impact components due to electrification and the need to shorten vehicle development time, shape optimization techniques are useful. However, crash analysis involves computationally expensive nonlinear analysis, making it unsuitable for shape optimization. This study developed an optimization method for impact components by using buckling strength obtained from linear analysis as the objective function.

A study on securing Torsional Stiffness in the Early Design Stage to Enhance Chassis Frame Durability

Namjin Kim･Gunwoo Nam･Geonhee Cheon･Eunsu Jang･Soosang Yoo･Hyun Sung･Jungsub Kim (Seojin Industrial)

Torsional loads during driving significantly impact the fatigue life and durability of a chassis frame. This study analyzes the correlation between torsional stiffness and durability performance. Initially, 1D element based analysis identified main design parameters regarding cross sections and thickness. These parameters were validated using a 2D flexible body finite element model for precise stiffness verification. Finally, durability analysis confirmed that increased stiffness effectively reducing stress and extends fatigue life. These results indicate that securing structural stiffness during the early design stage is critical for enhancing overall durability.

A Study of the Durability analysis method considering various contact conditions

JinHee Jang (Hyundai Motor)･DongJun Kim (Cadence)･MoonHo Yang (Hyundai Motor)

The durability performance directly related to safety is an item that must be satisfied. Because endurance testing requires a lot of cost and time, it is very efficient to evaluate simulation before testing. In this study, we examined the application of Nastran's recently developed Glue contact technology to the durability analysis of chassis components. And we developed a method to apply residual stress such as bolt pre-tension and pipe interference fit. Since the method implemented in this study can be used to study various boundary conditions in durability analysis.