Effects of Partial Forging on the Fatigue Strength of Cast Aluminum Alloys

Kento Shimizu･Mikiya Nozaki･Soichiro Ishida･Yoshihiro Maekawa･Masaaki Hirakawa･Kensuke Yoshizue (Toyota Motor)･Tomohiro Suzuki (Toyota Industries)･Takushi Isono (Toyota Motor)

Fatigue cracks in cast aluminum alloys are known to initiate from casting porosity defects. In this study, partial forging was applied to artificial defects simulating casting porosity, and the effects of defect size and defect crushing on fatigue strength were investigated. The experimental results showed that applying forging perpendicular to the principal stress direction affected the fatigue strength characteristics and crack propagation behavior.

Weight Reduction of Automotive Suspension Parts using 980MPa Class Steel

Takahiro Otani･Masaaki Tanaka･Hiroki Kimura (Mazda)

Vehicle dynamics performance and environmental performance are necessary for realization of " joy of driving " and "the superior environmental performance" that Mazda aims at. It is effective to reduce the thickness of stamping parts to send this thought to more customers. However, the coexistence at the high level of rigidity, strength, the anti-corrosion performance is demanded. I report the result that solved these problems by evolution of the elemental technology.

Investigation of Fatigue Characteristics of Adhesive–Rivet Hybrid Joints under Peel Loading

Chihiro Wada･Hiroaki Kawamura･Eita Niisato･Sohgo Takuno (Toyota Motor)

This study investigates the fatigue characteristics of adhesive–rivet hybrid joints for lightweight and multi-material automotive body applications. While previous studies have mainly focused on shear and tensile loading, the static and fatigue characteristics under peel loading were evaluated using specimens representing flange regions in vehicle bodies. The results show that fatigue behavior is governed by the rivet in the high-load region, whereas in the low-load region, load sharing by the adhesive improves fatigue strength.

Relationship between Void Distribution Function of Soft Polyurethane Foam and Mechanical Property (Compression Force - Displacement Characteristic)
-(Third Report) Compression Force - Displacement Characteristics Studies By Means of Void Distribution Function-

Minoru Inoue (Mazda/Kagawa University/Hirosima University)･Keisuke Suzuki (Kagawa University)･Hiroyuki Ito (Toyo Seat)･Toshihiro Yoshida (Mazda)

By means of CAE methodology to evaluate mechanical properties (compression force - displacement characteristics, hereafter F-S characteristics) of the soft urethane foams using void distribution function, which was verified and improved by the preceding papers, F-S characteristics studies by changing void distribution function curves were performed and executed. Then properties and parameters of void distribution functions which affect compression F-S characteristics are clarified and possibilities to control F-S characteristics of soft urethane foams are presented.

A Study on an Efficient Duct Component Evaluation Method Using Fluid Topology Optimization

Yoshio Itoh･Satoshi Ito (Toyota Motor)･Fumiya Shiratsu･Masahiko Kono･Toshiki Watanabe (Toyota Systems)

This study proposes an efficient HVAC duct design method based on fluid topology optimization. Conventional design relies on iterative CFD analysis and CAD modifications, resulting in high development effort. The proposed workflow enables automatic generation of optimized duct geometries while incorporating outlet boundary conditions, including downstream register effects. The results were validated through experiments using 3D-printed prototypes and a component test bench. It was demonstrated that outlet boundary conditions have a significant impact on pressure loss and optimized shapes. The proposed method improves performance under realistic operating conditions and reduces development effort by approximately 24 hours per phase.

Prediction of In-Cylinder States under Multiple Injection Conditions Using a Reduced-Order Model Derived from 3D CFD

Hiroki Nagashima･Ryo Adachi･Yousuke Eguro･Kouyou Nakagawa･Takuma Katsuragawa (SUBARU)･Natsuki Ishizawa (IDAJ)

Improving development efficiency is essential to achieve high performance, fuel economy, and emission reduction. Multiple injection strongly influences emissions, while 3D CFD analyses over a wide range of operating conditions require high computational cost. This study proposes a method to estimate in-cylinder states under various injection timings using a Reduced-Order Model (ROM) derived from CFD result.