Development of an economic concept for the static design of non through-welded seams in finite element analysis using an elastic-plastic material model

Finite element analysis (FEA) is gaining increasing importance in the design of steel structure connections. The aim of the research project is to improve weld design through a realistic elastic–plastic material model. By determining the material properties of the weld and employing practical geometry modeling, it is possible not only to optimize the load-bearing capacity of welded structures but also to reduce the modeling effort. The result provides significant advances in the cost-effectiveness of plastic design of welded structures.

Project name	Development of an economic concept for the static design of non through-welded seams in finite element analysis using an elastic-plastic material model
Akronym	FEA-Schweißnaht
Project partner	Technische Universität Darmstadt, Institut für Stahlbau und Werkstoffmechanik, Fachgebiet Stahlbau
Grantor	DLR
Duration	from 1.7.2025 to 30.6.2027
Research field	M+M (E+E > Energy + Environment I+I > Information + Intelligence M+M > Matter + Materials)
Project content	The design of steel structure connections using finite element analysis (FEA) is now common practice. Structural design work focuses on FE modeling and the evaluation of numerical results. The draft standard prEN 1993-1-14 aims to define application rules for FE analysis in steel construction; however, it does not cover the static design of welds. The objective of this research project is to develop an economical design concept for partially penetrated welds in FEA, including a geometry and material model as well as a coordinated verification method. The material behavior is analyzed using tensile tests, microsection examinations, and hardness measurements on welded test specimens. From the experimental results, material properties for the weld area and a limiting criterion for plastic strains in the FEA are derived. To validate the FE results, component tests on typical welded constructions are carried out. The intended research results will bring significant progress, particularly for small and medium-sized enterprises (SMEs) in the “building construction” and “metal production and processing” sectors. By providing simple geometry and material parameters, the modeling effort for planning offices in FEA is significantly reduced, leading to considerable time and cost savings. Furthermore, the elastic–plastic material model optimally activates the load-bearing capacity of the welds, thereby reducing the required calculated weld thicknesses. Fewer weld passes mean a significantly lower welding effort for manufacturing companies and a substantial reduction in production costs. In addition to improved cost-effectiveness, the concept also contributes to sustainability in construction. For example, older bridge structures can be verified and preserved despite increased loads, thanks to the more precise calculation methods.