Fatigue Analysis

Predictive engineering for welded joints and similar connections has always been challenging. Stress concentration in welded joints dominates fatigue behavior. But traditional finite element analysis (FEA) methods don’t consistently capture stress concentrations on welds. The geometric meshes created from models and used in FEA are not consistent regarding welds.

The world-famous Battelle National Laboratory has developed a mesh-insensitive approach to analyzing welded structures, known as the Verity® method. Verity® has been proven in variety of industries and with a wide variety of FEA software tools. Users of SIMULIA engineering simulation software have access to the Verity® method as an option to the Abaqus FEA portfolio, Verity® for Abaqus. It also works with the SIMULIA Fe-Safe module for fatigue analysis.

Verity® for Abaqus works by mapping nodal forces along an arbitrary weld line, created by a typical FEA analysis. The complexities of stress states along the weld line due to notch effects can then be studied and presented as structural mechanics issues of membrane thickness and bending at each nodal location.

Engineers can now use Verity® for Abaqus to easily and accurately predict consistent stress characterizations for welded joints in pressure vessels, piping, storage tanks, offshore platforms, and construction equipment, among many other applications. Verity® technology is also suitable for structures with geometrical notches such as adhesive joints, mechanically fastened joints, electronic packages, and manufacturing notches that are subject to stress concentrations. The method has been adopted in the American Society of Mechanical Engineers (ASME) Division 2 Code and API 579/ASME FFS-1 Codes for Fitness-for-Service assessments based on allowable stress methods and plastic collapse loads.

Industry examples

In the nuclear power industry, Verity® for Abaqus helps engineers to more accurately evaluate weld performance of mission-critical components and systems such as pressure vessels to reduce maintenance and in-situ physical inspection. In the oil and gas industry, benefits include improved operational availability of physical systems such as pipelines and offshore structures.

Meeting regulations for structural stress of welded joints requires advanced technology. By combining Verity® technology with Abaqus, SIMULIA offers a unique simulation solution which allows companies to analyze accurate weld performance. This leads to lower development costs, and accelerated design and implementation processes.