鋁輪圈衝擊測試之模擬分析

Modeling for Impact Test of Aluminum Wheels

張維展(Wei-Chan Chang)

指導教授 ： 林志光

國立中央大學/工學院/機械工程學系/碩士(2008年)

摘要

本研究主旨在利用有限元素分析法(FEA)探討在衝擊測試過程中輪胎對於鋁輪圈衝擊性能之影響，並且尋找一個能夠等效於動態衝擊效應的靜態分析方法。本研究分析三款鋁輪圈，模擬其在承受動態負載的情況下，考慮一部份的衝擊能被輪胎所吸收來補償未包含輪胎作用之有限元素模型，並且分析此狀態下之衝擊行為。此外，亦建立一個使用等效靜態負載來模擬動態衝擊測試的分析模型。
分析結果顯示，經由實際衝擊測試後所量測的輪圈底部胎環直徑改變量與動態模擬結果作比對，可估算出在衝擊過程中輪胎將會吸收一適當比例之衝擊能，而此吸收量可進一步利用塑性功和破壞應變準則加以確認。在這三款輪圈中，除了B形式輪圈利用這兩種破壞準則所估算之吸收量比利用胎環直徑改變量所估算的結果來的低之外，其餘兩種輪圈皆有相當接近於量測直徑改變量的結果。對於A、B、C這三種形式的輪圈而言，所估算輪胎適當的衝擊能吸收量分別為47.1% - 60.8%、12.5% - 28.3%以及20.1% - 32.4%。另外，根據這兩個破壞準則，在有限元素動態分析中可準確的預測出鋁輪圈破損可能發生的位置。
本研究利用將衝錘重量放大14到18倍所建立的等效靜態分析模式，能夠對此三種形式輪圈因承受動態負載所造成的衝擊效應做出有效的描述。在靜態分析中，利用等效塑性應變分佈並配合破壞應變準則能夠獲得一個較保守的預測，而且亦能夠準確地預測出鋁輪圈破損發生的位置。

關鍵字

電腦模擬 ； 衝擊測試 ； 鋁輪圈

並列摘要

The aim of this study is, by using finite element analysis (FEA), to investigate the effect of the tire portion on the wheel impact performance and to find an effective way for replacing the dynamic impact effect by a static loading. Three types of wheels (Type A, Type B, and Type C) were applied in the current study to simulate the impact behavior caused by a dynamic loading with consideration of a certain percentage of impact energy absorption to compensate for the tire absence in the FEA models. In addition, a simple methodology for simulation of a dynamic impact test by an equivalent static loading was developed.
The appropriate percentage of the impact energy absorbed by the tire portion was determined through a comparison of the experimentally measured changes of the bottom rim flange diameters with the dynamic simulation results and further confirmed by applying the plastic work and fracture strain criteria. The predicted absorption percentage based on the given two failure criteria for the given three types of wheels were well correlated with those determined by the changes of the bottom rim flange diameters except for the Type B wheel with a lower predicted value. The estimated absorption percentage for the Type A, Type B, and Type C wheels was in the range of 47.1% to 60.8%, 12.5% to 28.3%, and 20.1 % to 32.4%, respectively. The potential failure location could be accurately predicted by the FEA dynamic modeling in accordance with the applied two failure criteria.
An effective static simulation with a static load equivalent to a certain number (14 to 18) times the striker weight was developed and could well describe the impact effect of the dynamic loading for the given three types of wheels. In the static analysis, a conservative prediction was obtained by the failure criterion based on the equivalent plastic strain with an accurate prediction of the critical region.

並列關鍵字

impact test ； computer simulation ； aluminum wheels

參考文獻

5. W.-R. Chen, “Computational Analysis of Impact Testing on Aluminum Wheels,” Hua Kang Journal of Engineering, Vol. 10, 1996, pp. 163-184.

7. “Light Alloy Disc Wheels for Automobiles,” CNS 7135, Chinese National Standards, Bureau of Standards, Metrology and Inspection, Ministry of Economic Affairs, R.O.C, 1995.

1. P. Li, D. M. Maijer, T. C. Lindley, and P. D. Lee, “A Through Process Model of the Impact of In-Service Loading, Residual Stress, and Microstructure on the Final Fatigue Life of an A356 Automotive Wheel,” Materials Science and Engineering A, Vol. 460-461, 2007, pp. 20-30.

2. R. Shang, W. Altenhof, N. Li, and H. Hu, “Wheel Impact Performance with Consideration of Material Inhomogeneity and a Simplified Approach for Modeling,” International Journal of Crashworthiness, Vol. 10, 2005, pp. 137-150.

6. Y.-L. Hsu and M.-S. Hsu, “Weight Reduction of Aluminum Disc Wheels under Fatigue Constraints Using a Sequential Neural Network Approximation Method,” Computers in Industry, Vol. 46, 2001, pp. 167-179.