44.2. Problem Description

44.2.1. Rectangular Block with a Semicircular Surface Flaw

This model is fixed at one face of the block. A pressure load is applied on the opposite face. The block has a semicircular surface flaw with a 20 mm radius at the center of one longitudinal face in the thickness direction; the crack is perpendicular to one of the surfaces of the rectangular block.

Figure 44.1: Rectangular Block Geometry with Semicircular Surface Flaw

Rectangular Block Geometry with Semicircular Surface Flaw

A torus is created around the crack front to control the mesh at the crack front. Following is the semicircular crack and torus along the crack front used to create a sweep mesh with the SOLID186 3D 20-node structural solid (brick) element:

Figure 44.2: Semicircular Crack and Torus Along the Crack Front

Semicircular Crack and Torus Along the Crack Front

44.2.2. X-Joint Pipe with Warped Surface Flaw

A semi-elliptical warped surface flaw at the tubular joint is analyzed to obtain the C*-integral along the crack front:

Figure 44.3: X-Joint Pipe Full Model with Warped Surface Flaw at Welded Joint

X-Joint Pipe Full Model with Warped Surface Flaw at Welded Joint

The problem consists of two tubular members attached to each other by a welded joint. The tubular members (labeled Tube 1 and Tube 2) have outer diameters of 323.85 mm (D1) and 219.08 mm (D2), and thicknesses of 15.88 mm (t1) and 8.18 mm (t2), respectively. The semi-elliptical surface crack lies on a plane parallel to the radial direction of the heavier running pipe.

A torus is created around the crack front to control the mesh at the crack front. The semi-elliptical surface crack at the weld toe is warped along the welded joint and it is perpendicular to the outer surface of the 323.85 mm diameter pipe in the thickness direction.

Figure 44.4: Semi-elliptical Surface Crack Dimensions

Semi-elliptical Surface Crack Dimensions

The warped crack profile at the welded joint is created via the interaction of a rotated semi-ellipse on the 323.85 mm diameter pipe and an extruded circle normal to the inner surface of the same pipe at the welded joint:

Figure 44.5: Two-plane Symmetry of X-joint Pipe with Warped Surface Flaw Geometry

Two-plane Symmetry of X-joint Pipe with Warped Surface Flaw Geometry