This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
A Program for the Fatigue Analysis of Automotive Spot-Welds Based on Finite Element Calculations
Annotation ability available
Sector:
Language:
English
Abstract
A Software system has been developed which permits fatigue life predictions to be made for automotive spot welds joining two steel sheets, based on finite-element analyses. The method requires the spot welds in a structure to be modelled as stiff bar elements in a relatively coarse mesh, with the bar elements acting as force transducers. The method uses the bar element cross sectional forces and moments to calculate the “structural stresses” in each spot-weld nugget and the adjacent sheets.
The system permits the user to play complex loading histories through a finite element model, using either a quasi-static or transient approach to stress history determination. The method provides a convenient way to predict the locations and lives of fatigue sensitive spot welds, and includes graphical tools to assist in interpretation of results. Studies so far indicate that in a typical application such as an automotive body structure, the system correctly identifies all the spot welds that are likely to give rise to durability problems. Using generic S-N curves, life predictions made so far have tended to be somewhat conservative. When S-N curves are used which are more representative of the material from which the component is constructed, more accurate life predictions can be made.
Authors
Topic
Citation
Heyes, P. and Fermer, M., "A Program for the Fatigue Analysis of Automotive Spot-Welds Based on Finite Element Calculations," SAE Technical Paper 962566, 1996, https://doi.org/10.4271/962566.Also In
References
- Rupp, A. Störzel, K. Grubisic, V. “Computer Aided Dimensioning of Spot-Welded Automotive Structures,” Technical Paper 950711 ., SAE 1995
- Smith R. A. Cooper, J. F. “Theoretical predictions of the fatigue life of shear spot welds” Fatigue of Welded Structurers Maddox S. J. 287 293 1988
- British Standards Institutions “Code of Practice for Fatigue Design and Assessment of Steel Structures,” BS 7608 1993
- Radaj, D. “Local Fatigue Strength Characteristic Values for Spot Welded Joints,” Engineering Fracture Mechanics 37 1 245 250 1990
- Shepard S.D. Strange, M.E. “Fatigue Life Estimation in Resistance Spot Welds; Initation and Early Growth Phase,” Fatigue and Fracture of Engineering Materials and Structures 15 6 531 549 1992
- Sheppard, S.D. “Estimation of Fatigue Propagation Life in Resistance Spot Welds,” ASTM STP 1211, Advances in Fatigue Life Prediction Techniques Mitchell M. R. Landgraf R. w. 169 185 ASTM Philadephia. 1993
- “MSC/FATIGUE User's Manual,” Version 1.4 The MacNeal Schwendler Corporation Los Angeles, C.A. March 1995
- Heyes, P. Dakin J. SJohn, C. “The Assessment and Use of Linear Static FE Stress Analysis for Durability Calculations,” Technical Paper 951101 , SAE 1995
- “MSC/NASTRAN Quick Reference Guide,” Version 68 MacNeal Schwendler Corporation Los Angeles, CA. 1994
- “MSC/PATRAN User's Manual,” Version 1.4,” The MacNeal Schwendler Corporation Los Angeles, CA. March 1995