Fracture Limit Curve Development on ABW (Arc Brazing Weld) Considering Joint Efficiency in LS-DYNA3D

Arc brazing welding (ABW) is widely used in automotive vehicle body and chassis structure along with Arc welding - MIG (Metal Inert Gas) or TIG (Tungsten Inert Gas) and spot welds. MIG welding or ABW (Arc Brazing welding) fracture in vehicle development process is one of the critical phenomena in quasi static structural simulation, like Roof Strength, Seat/Belt Anchorage and Child Restraint Anchorage (CRS). MIG/ABW Fracture has an impact on structural performance. Advantages of ABW over MIG weld is made at relatively lower temperatures. Significant advantage is welding thin sheet metal, no melting of parent metal and retains significant physical properties. This characteristic of ABW enables selection of ABW against MIG welded joint on automotive thin sheet metals. Good ABW joint can be as strong or stronger than MIG welded joint. Joint efficiency (JE) is defined as the ratio between the fracture strength of the joint and the fracture strength of parent metal. A joint efficiency of 100% means that the fracture strength of the joint at least equals the strength of the parent metal. It is the most critical parameter of Arc Brazing characteristics.

In this paper, development of GISSMO damage model on solid Arc Brazing weldment based on HC (Hosford-Coulomb) fracture characterization in DYNA-3D [1] is demonstrated. Also, developed how to define joint efficiency in simulation and physical coupon tests for Arc Brazing variations around ISOFIX wire for Child Seat Anchors. Finally, fracture model for Arc Brazing weldment is applied and validated at vehicle level for FMVSS225 [6] CRS load cases.