Fatigue life calculation of welded joints based on fracture mechanics英文电子书.pdf

Institut of Materials Engineering PHD Programme Fatigue life calculation of welded joints based on fracture mechanics Ahmed M. Al-Mukhtar* MSc. Materials and Manufacturing Engineering BSc. Aeronatical Engineering Supervisors: Prof. Dr.- Ing. habil. H. Biermann* Prof. Dr.- Ing. P. Hübner** *Institute of Materials Engineering, Technische Universität Bergakademie Freiberg, Germany **Fachhochschule Mittweida, Mittweida, Germany Outlines 1) Aim of reaserch (Objectives) - Procedure 2) Introduction (Why fracture mechanics?) 3) Finite Element Analysis (FEA) - Modelling - Crack path direction 4) Standard and fatigue design recommendations 5) Results (benchmarking) - SIF calculation and comparison for some welded joints - Fatigue life calculation and comparison for some welded joints - Case study not presented in the recommendation 6) Conclusions 2 1. Aim and Proecdures 1. Ziel – und Aufgabenstellung Aim - Accurate SIF calculation - Moreover, calculate the fatigue life, and the fatigue strength (FAT) of the welded joints with different geometries that not presented in recommendations Procedures 1) FE modeling which give accurate stress intensity factor. 2) With knowledge of the stress intensity factors KI at different crack depths (a), it was possible to make curve fits for KI(a) for the different loading and use Paris’ law to integrate numerically and calculate the expected fatigue life for the specimens. 3) Case studies can be consulted, and the need for well thought out benchmarking of analytical results against experimental databases-IIW