KSME International Journal

, Volume 15, Issue 1, pp 44–51 | Cite as

Fatigue strength assessment of spot-welded lap joint using strain energy density factor

Materials & Fracture · Solids & Structures · Dynamics & Control · Production & Design


One of the recent issues in design of the spot-welded structure such as the automobile body is to develop an economical prediction method of the fatigue design criterion without additional fatigue test. In this paper, as one of basic investigation for developing such methods, fracture mechanical approach was investigated. First, the Mode I, Mode II and Mode III, stress intensity factors were analyzed. Second, strain energy density factor (S) synthetically including them was calculated. And finally, in order to decide the systematic fatigue design criterion by using this strain energy density factor, fatigue data of the δP-N f obtained on the various in-plane bending type spot-welded lap joints were systematically re-arranged in the °S-N f relation. And its utility and reliability were verified by the theory of Weibull probability distribution function. The reliability of the proposed fatigue life prediction value at 107 cycles by the strain energy density factor was estimated by 85%. Therefore, it is possible to decide the fatigue design criterion of spot-welded lap joint instead of the δP-N f relation.

Key Words

Spot Welding IB (in-plane bending) Type Specimen Fatigue Strength Stress Intensity Factor Strain Energy Density Factor Reliability 


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Copyright information

© The Korean Society of Mechanical Engineers (KSME) 2001

Authors and Affiliations

  1. 1.Lab, Test TeamSsangyong Motor Co.Kyunggi-doKorea
  2. 2.School of Mechanical EngineeringSungkyunkwan UniversityKorea

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