A review of multiaxial fatigue of weldments: experimental results, design code and critical plane approaches

Abstract

A survey of biaxial (bending or tension and torsion) constant amplitude fatigue of welded connections is presented. Re‐analysis of 233 experimental results from eight different studies has been performed based on hot spot stresses and three potential damage parameters: maximum principal stress range; maximum shear stress range; and a modified critical plane model for welds. Of the three methods, the critical plane model was most successful in resolving the data to a single S–N line. The design curve for all toe failures based on the critical plane model was FAT 97 with a slope of 3. By excluding butt welds and including only fillet welds that failed at the weld toe, the design curve was increased to FAT 114 with a slope of 3. However, observed scatter was 70–100% larger than that observed in uniaxial loaded specimens analysed using the hot spot approach.

A fretting related damage parameter for fretting fatigue life prediction

“…The critical plane is defined as the plane experiencing the largest value of f. Some researchers [36,37] assume that it can be defined as the maximum shear stress range plane.…”

A Review of Critical Plane Orientations in Multiaxial Fatigue Failure Criteria of Metallic Materials

“…Findley did not defined a mathematical formula for coefficient f . Some researchers (Park and Nelson, 2000;Backstrom and Marquis, 2001) assume that it can be determined from the shear-mode cracking Mcdiarmid criterion (1972Mcdiarmid criterion ( , 1990Mcdiarmid criterion ( ) (mcdiarmid, 1985Mcdiarmid criterion ( , 1987diebmann and bhongbhibhat, 1991) McDiarmid noticed that important parameters of loading in high cycle fatigue (HCF) regime are the maximum shear stress range and the normal stress in the critical plane. The critical plane in this criterion is the plane of maximum shear stress range.…”

Refined Analysis of Fatigue Crack Initiation Life of Beam-to-Column Welded Connections of Steel Frame under Strong Earthquake

“…Since the mechanism of the fatigue crack initiation for the structural steel satisfies the metal crystal slip theory, fatigue crack initiation occurs on the plane with the maximum shear strain, which can be defined as the critical plane according to the multiaxial fatigue theory [21,22]. If the strain state is proportional, the angle of the critical plane is constant, while if the strain state is nonproportional, the angle time history of the critical plane varies.…”