The engineering treatment model (ETM) and its practical application

Fitness for purpose assessments of flawed structures require information on the driving force acting on the crack. In spite of the availability of powerful finite element codes formulae are needed which serve for estimating the crack driving force. The lack of precision in detail - as compared with finite element calculations - is balanced by the possibility to do quick estimates; furthermore, a formula shows immediately how the relevant parameters affect the result. With this in mind, work has been carried out at GKSS Research Centre to develop and to verify a method providing best estimates for the crack tip opening displacement (CTOD), the J-integral, and the load point displacement. This method has been named the Engineering Treatment Model (ETM). The present communication presents a compilation of the formulae developed and provides guidance for the prospective user on how to use the ETM. (orig./MM)