Bertin D. Soh Fotsing

On the efficiency of the integral approach in multiaxial fatigue

Abstract The design of structures or mechanical components against multiaxial fatigue generally requires the use of one multiaxial fatigue criterion. Many models have been proposed. The aim of the present paper is to focus on the most recent concept that is named the integral approach. Its main feature is to assess the fatigue damage at the analysed point of the structure from stress averages realised over all the material sectional planes passing through this point. The different propositions are first presented and their efficiency is then discussed and compared with the fatigue prediction obtained by criteria based upon the critical plane concept. It definately seems that the contribution of several damaged physical planes agrees with the actual fatigue behaviour of metals in a better manner than by considering the stresses acting on one single sectional plane.

Fatigue Equivalent Stress State Approach Validation in Non-conservative Criteria: a Comparative Study

This paper is concerned with the fatigue prediction models for estimating the multiaxial fatigue limit. An equivalent loading approach with zero out-of-phase angles intended for fatigue limit evaluation under multiaxial loading is used. Based on experimental data found in literatures, the equivalent stress is validated in Crossland and Sines criteria and predictions compared to the predictions of existing multiaxial fatigue; results over 87 experimental items show that the equivalent stress approach is very efficient.

Fatigue Safety Coefficient Based Mutual Comparison of the Simple Working Regime of Hermetic Compressor Suspension Springs

Compressors suspension made up of helical suspension spring system has a significant importance on the operation of hermetic compressors, considering the aspects of noise and vibration. These springs are loaded by harmonic forces very often. High cycles fatigue damage and failure can be found during its service loading. The severity of lading regime has been studied for three typical loading regimes of springs using the fatigue safety factor. The spring fails by fatigue not yielding; infinite life is not predicted. All cases are demonstrated in the Haigh diagram. Finite life is predicted. It has been showed that loading cases with constant mean shear give lowest safety factor than the proportional or constant middle stress regimes.