Prediction of structural behaviour on the basis of small-scale specimen testing: PRESS

The research project has been directed towards developing quantitative materials and design practice requirements for structures fabricated from advanced high strength steels. Manufacturers of advanced high strength steels and welding consumables, engineering and fabrication companies and experienced end users have jointly been cooperating together with research institutes to select the most attractive steel grades and define the requirements for the weldments of the new class of steels. The planned research work was grouped into several main phases: Evaluation of the available results from the preceding multipartner projects (Local approach, J - Q - M concept ) Establishing a modified evaluation procedure based on Weibull stress and J - Q - M concept (generation of input data, sensitivity studies, parameter study for main input variables) Extension of the approach (limited plastic deformation and ductile tearing, damage mechanics and J - Q - M) Verification of the modified concept for 500 MPa yield strength weldments Application of the new concept to 690 MPa yield strength steel weldments Development of user oriented guidelines for the application of the new concept The major research tasks have been: Selection of steels and welding consumables Weld thermal simulation testing Mechanical- and fracture toughness testing Design practice for high strength steels FEM calculations Statistical evaluations Application of the concept to structural components, comparison of safety levels with standardized procedures and recommendations for modification. Recommendations are given for the use of 690 MPa structural steels with requirements on material and welding procedure, the application of the new failure assessment concept with details on testing procedure, treatment of scatter, material model and failure criterion, procedure for J-Q-M evaluation, validation examples and limitations.