Problems of fatigue under multiaxial fatigue loads have been addressed in a very large number of research publications. The present publication is primarily a survey of biaxial fatigue under constant amplitude loading on metal specimens. It starts with the physical understanding of the fatigue phenomenon under biaxial fatigue loads. Various types of proportional and non-proportional biaxial fatigue loads and biaxial stress distributions in a material are specified. Attention is paid to the fatigue limit, crack nucleation, initial micro crack growth and subsequent macro-crack in different modes of crack growth. The interference between the upper and lower surfaces of a fatigue crack is discussed. Possibilities for predictions of biaxial fatigue properties are analysed with reference to the similarity concept. The significance of the present understanding for structural design problems is considered. The book is completed with a summary of major observations.

The European Structural Integrity Society (ESIS) Technical Commitee on Fatigue of Engineering Materials and Structures (TC3) decided to compile a Special Technical Publication (ESIS STP) based on the 115 papers presented at the 6th International Conference on Biaxial/Multiaxial Fatigue and Fracture. The 25 papers included in the STP have been extended and revised by the authors. The conference was held in Lisbon, Portugal, on 25-28 June 2001, and was chaired by Manual De Freitas, Instituto Superior Tecnico, Lisbon. The meeting, organised by the Instituto Superior Tecnico and sponsored by the Portuguese Minesterio da Cienca e da Tecnologia and by the European Structural Integrity Society, was attended by 151 delegates from 20 countries. The papers in the present book deal with the theoretical, numerical and experimental aspects of the Multiaxial fatigue and fracture of engineering materials and structures. They are divided in to the following six sections; Multiaxial Fatigue of Welded Structures; High cycle Multiaxial fatigue; Non proportional and Variable-Amplitude loading; Defects, Notches, Crack Growth; Low Cycle Multiaxial Fatigue; Applications and Testing Methods. As is well-known, most engineering components and structures in the mechanical, aerospace, power generation, and other industries are subjected to multiaxial loading during their service life. One of the most difficult tasks in design against fatigue and fracture is to translate the information gathered from uniaxial fatigue and fracture tests on engineering materials into applications involving complex states of cyclic stress-strain conditions. This book is the result of co-operation between many researchers from different laboratories, universities and industries in a number of countries.

The 36 paper spresented in this volume were presented at the second international conference on biaxial/multiaxial fatigue.

This book provides practicing engineers, researchers, and students with a working knowledge of the fatigue design process and models under multiaxial states of stress and strain. Readers are introduced to the important considerations of multiaxial fatigue that differentiate it from uniaxial fatigue.

Master's Thesis from the year 1997 in the subject Engineering - Mechanical Engineering, , language: English, abstract: A study of metal cumulative fatigue damage at multilevel stress programs using 2024- T 4 AI -Alloy is carried out in this investigation. Specimens are designed and fabricated. The tests are performed under multiaxial fatigue in phase combined loading bending and torsion, with zero mean stress (R=-l) at room temperature. Five groups of multiaxial fatigue experiments are performed, constant amplitude, linear increasing and decreasing, Low-High loading sequence, High-Low loading sequence and equivalent flight loading fatigue. Prediction of life specimens are studied at three methods: Palmgren-Miner, Corten - Dolan, and Marsh. The methods are conservative to some specimens and non-conservative to another. The effects of stage life (ns) have been examined and fatigue life of specimens are decreased when the stage life is decreased. Comparisons between High-Low & Low-High loading sequences in fatigue life (multi stress level) have been investigated. The Low-High loading sequence is less dangerous than High-Low loading sequence at the same stress range (equal loading stages). Studies the effect of stress range fatigue life have been investigated and the fatigue life is decreased with increasing the stress range fatigue (having the same lowest stress). For the fatigue of equivalent flight loading, the life is depend basically on stress range and the cruising interval this two parameters have been studied.