Transactions of the Korean Society of Mechanical Engineers A (대한기계학회논문집A)

The Korean Society of Mechanical Engineers (대한기계학회)
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Energy Absorption Characteristics and Optimal Welding Space of Square Hat Type Thin-walled Tube

정사각 모자형 박판튜브의 에너지흡수특성 및 최적 용접간격

  • 이형일 (서강대학교 기계공학과) ;
  • 김범준 (현대·기아 연구개발본부, 응용 의장설계 3팀) ;
  • 한병기 (홍익대학교 기계공학과)
  • Published : 2002.12.01
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Abstract

In this work, energy absorption characteristics and optimal welding space of spot-welded square hat type tube are investigated via quasi-static crush experiments and finite element (FE) analyses. A FE model reflecting the crush characteristics is established based on the experimentally observed crush mechanisms of specimens with welding spaces (20, 30 & 45 mm) and (25,40 & 55 mm) respectively for two specimen widths (60, 75 mm). The established FE model is then applied to other crush models of widths (50, 60 & 75 mm) with various welding spaces (20, 25, 30, 40, 45, 55, 75, 150, 300 mm) respectively. We examine the energy absorption characteristics with respect to the welding space for each specimen width. The outcome suggests an optimal spot welding space of square hat type thin-walled tube. Energy absorption is also presented in terms of yield strength of base metal, specimen thickness, width, and mean crushing force of spot-welded square hat type thin-walled tube.

본 연구에서는 유한요소해석을 통해 점용접된 정사각 모자형 박판튜브의 적정 용접간격을 제시해보았다. 적정 용접간격은 에너지흡수 측면에 기준을 두었다. 이를 위해 먼저, 실제 압괴특성을 반영하는 유한요소 모델이 확립하였다. 실제 압괴 특성을 반영하는 유한요소 모델은 본 연구에서 수행된 실험결과에 기초하여 설정하였다. 이 과정에서 다음과 같은 결과들을 도출하였다. (1) 모자형 박판튜브의 압괴해석시 원활한 접힘을 유도하고 과도변형과 접촉에 의한 수치오류 및 비정상 압괴거동을 방지하기 위해 적정 요소크기와 해석시간에 대한 예비연구가 필요하다. (2) 다양한 용접간격의 유한요소모델들에 대한 압괴해석을 거쳐 주어진 폭에 대해 최대 에너지 흡수 용접간격 [식 (1)]을 제시하였다. 또한 최적용접 간격의 모자형 박판튜브는 후폭비 (t/w)가 커질수록 에너지흡수능력 이 증가한다. (3) 다양한 두께와 폭을 갖는 사각튜브에 대한 유한요소해석을 통해, 사각튜브 흡수에너지 예측에 있어 평균압괴하중 방법의 유효성을 검증하였다. 이를 토대로 후폭비항으로 표현되는 수정된 평균 압괴하중으로 최적용접간격을 갖는 모자형 박판튜브의 흡수에너지식 (5)를 제시하였다. 식 (5)의 적용시, 주어진 폭에 대해 (최적)용접간격을 유지함과 동시에 식 (6)의 한계후폭비를 만족해야 한다.

Keywords

References

  1. Lee, T. S., Lee, H. and Shin, S., 1998, 'An Estimative Model of Sport Weld Failure - 1. Failure Criteria,' Journal of Korea Society of Automative Engineer, Vol. 6, No. 6, pp. 40-52
  2. Shin, S., Lee, H., Lee, T. S. and Choi, Y. W., 1999, 'An Estimative Model of Spot Weld Failure - 2. Panel Structure Analysis,' Journal of Korea Society of Automotive Engineer, Vol. 7, No. 1, pp. 161-172
  3. Lee, H., Kim, N. and Lee, T. S., 2000, 'An Experimental Investigation of Limit Loads and Fatigue Properties of Spot Welded Specimens,' Transactions of KSME, Vol. 24, No. 1, pp. 38-51
  4. Kim, N. and Lee, H., 2000, 'Spot Weld Fatigue Life Prediction of Auto Seat Belt Anchors Using$K_e$,' Transactions of KSME, Vol. 24, No. 3, pp. 701-709
  5. Lee, H. and Choi, J., 2000, 'Overload Analysis and Fatigue Life Prediction Using an Effective J-integral of Spot Welded Specimens,' Transactions of KSME, Vol. 24, No. 3, pp. 567-580
  6. Choi, J. and Lee, H., 2000, 'Overload Analysis and$J_e$Based Fatigue Life Prediction of Spot-Welded Auto Seat Belt Anchors,' Transactions of KSME, Vol. 25, No. 4, pp. 662-670
  7. Timoshencho, S. T. and Gere, J. M., 1961, Theory of Elastic Stabilituy, 2nd Edition, McGraw-Hill Co., New York
  8. Ohkubo, Y., Akamatsu, T. and Shirasawa, K., 1975, 'Mean Crushing Strength of Closed Hat Section Members,' SAE paper 750040
  9. Wierzbicki, T. and Abramowicz, W., 1983, 'On the Crushing Mechanics of Thin-walled Structures,' Journal of Applied Mechamics, Vol. 50, No. 4, pp. 727-734 https://doi.org/10.1115/1.3167137
  10. Abramowicz, W., 1983, 'The Effective Crushing Distance in Axially Compressed Thin-walled Metal Columns,' International Journal of Impact Engineering, Vol. 1, No. 3, pp. 309-317 https://doi.org/10.1016/0734-743X(83)90025-8
  11. Abramowicz, W., and Jones, N., 1986, 'Dynamic Progressive Buckling of Circular an Square Tubes,' International Journal Impact Engineering, Vol. 4, No. 4 pp. 243-270 https://doi.org/10.1016/0734-743X(86)90017-5
  12. Wierzbicki, T. and Abramowicz, W., 1989, 'Axial Crushing of Multi-corner Sheet Metal Columns,' Journal of Applied Mechanics, Vol. 56, No. 4, pp. 113-120 https://doi.org/10.1115/1.3176030
  13. Mamalis, A. G., 1988, 'On the Crumpling of Thin Plastic Closed Top-hat Sections by Compressive Loading,' International Journal Vehicle Design, Vol. 9, No. 10, pp. 675-688
  14. Mamalis, A. G., 1989, 'The Extensional Axial Collapse of Thin Plastic Double Top-hat Sections,' International Journal Vehicle Design, Vol. 10, No. 3, pp. 269-283
  15. Bleich, F., 1952, Buckling Strength of Metal Structures, McGraw-Hill Book Co., New York
  16. Gerard, G., 1962, Introduction to Structural Stability Theory, McGraw-Hill Book Co., New York
  17. Mahmoood, H. F. and Paluszny, A., 1981, 'Design of Thin Walled Columns for Crash Energy Management-Their Strength and Mode of Collapse,' SAE paper 811302
  18. Tani, M. and Funahashi, A., 1978, 'Energy Absorption by the Plastic Deformation of Body Structural Members,' SAE paper 780368
  19. Kim, C. W. and Han, B. K., 1994, 'A Study on the Crushing Mechanics of Thin-walled Structures,' Vol. 2, No. 1, pp. 65-72
  20. ABAQUS/Explicit(Version 5.8) User's Manual, 1998, Hibbitt, Karlsson and Sorensen, Inc., Pawtucket, RI
  21. ABAQUS/Explicit(Version 5.8) User's Manual Hibbitt, Karlsson and Sorensen, Inc.