INTERNATIONAL CONGRESS ON RECENT ADVANCES IN SCIENCES AND TECHNOLOGY - Kuala Lumpur - Malaysia (2019-02-20)

Simulation of Steel Used in Shipbuilding Structures using CZM
Shipbuilding structure is huge with complex geometry. Due to complex geometry stress concentration always present at or near the welded joints. Additionally flaws or discontinuities in welded ship hull become sources of stress raiser. Therefore consideration of fracture mechanics approach is as important aspect in shipbuilding design. Present study aims to simulate the fracture behavior of plane carbon steel which is generally used for shipbuilding applications. Tensile and fracture tests are performed on 12.5 mm thick plate for evaluation of mechanical properties and fracture toughness respectively. Tensile test specimens are prepared as per the ASTM E8M. For fracture test, compact tension type specimens are used. J-integral is considered as fracture toughness parameter. Compact tension specimens are prepared according to ASTM E1820 standards. The cohesive damage model is selected because its fundamentally based on fracture energy and ductile resistance. Suitable approaches are used to finalize cohesive parameters. For simulation, FEM & XFEM models are prepared. Load values are underestimated in case of finite element method whereas extended finite element method gives more accurate results. Therefore for further study only XFEM model is considered. To simulate fracture process zone, partly constant, fully constant and exponential traction-separation laws are selected. All of them show better result correlation with experimentation. Effect of cohesive stiffness variation is investigated within range of 0.5 times modules of elasticity to 100 times modules of elasticity. As cohesive stiffness value increases beyond ten times of modules of elasticity, the material start fracture by cleavage manner.
Dr. Vikas Chaudhari, Mr. Swadesh Dixit