Professor Ewald Macha's contribution to the development of methods for multiaxial fatigue life estimation

Multiaxial fatigue of machine elements and construction is still a remarkable problem in everyday life. Many accidents were consequences of inaccurate estimation of stresses and fatigue life. Despite many years of work and research on the subject, fatigue life estimation is still very important to be examined. Professor Ewald Macha was a researcher involved in the development issues of fatigue life estimation and, in particular, was interested in multiaxial fatigue failure criteria based on the critical plane approach, where he formulated the stress, strain and strain energy density criteria. Particularly noteworthy are the methods for determination of the critical plane position. In this field, Professor Macha proposed a weight function method, and then a variance method. These methods have been verified experimentally. Professor Macha also proposed a method for determination of the energy fatigue characteristics, especially for cyclically unstable materials. This paper describes the scientific achievements of Professor Macha.