Application of element deletion method for numerical analyses of cracking

Purpose: To develop a numerical algorithm to simulate cracking and its evolution for machining, shearing and multi-pass hot bar rolling processes. Design/methodology/approach: Element deletion method was adopted for developing a numerical algorithm and implemented to a rigid-viscoplastic finite element program. Cockcroft-Latham and specific plastic work criteria were incorporated in the present investigation for simulating cracking and shearing processes. An instability condition for the tension was assumed to be valid to determine a critical damage factor for initiation of possible cracking. Findings: The developed element deletion algorithm was simple to be applied for simulating cracking and shearing patterns for the processes applied. Cockcroft-Latham and specific plastic work fracture criteria were reasonable in predicting the internal and external crack, respectively. Research limitations/implications: The research finding can be utilized for investigating occurrence of external and internal cracking involved with metal forming processes such as Chevron cracking in extrusion. Practical implications: By expanding the current approach to determine a processing map for extrusion the processing condition to prevent Chevron cracking can be determined easily and utilized in industry. Also, the current investigation can be easily expanded to other process design and control. Originality/value: Numerical algorithm based on the element deletion method was developed and implemented to the existing finite element program to examine the processes including cracking phenomenon. The applicability to utilize a critical damage factor for the fracture criteria based on the instability was evaluated.

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