A new numerical method for determining collapse load-carrying capacity of structure made of elasto-plastic material

• Published in: Journal of Central South University Vol. 21; no. 1; pp. 398 - 404
• Main Authors: Zhong, Zhi-peng, Ren, Da-long, Wan, Shui
• Format: Journal Article
• Language: English
• Published: Heidelberg Central South University 2014
• Subjects: Engineering; Metallic Materials; elasto-plastic material; incremental-iterative analysis; non-linear finite element method; damped Newton method; collapse load
• ISSN: 2095-2899; 2227-5223
• DOI: 10.1007/s11771-014-1953-0

Determination of collapse load-carrying capacity of elasto-plastic material is very important in designing structure. The problem is commonly solved by elasto-plastic finite element method (FEM). In order to deal with material nonlinear problem involving strain softening problem effectively, a new numerical method-damped Newton method was proposed. The iterative schemes are discussed in detail for pure equilibrium models. In the equilibrium model, the plasticity criterion and the compatibility of the strains are verified, and the strain increment and plastic factor are treated as independent unknowns. To avoid the stiffness matrix being singularity or condition of matrix being ill, a damping factor
α
was introduced to adjust the value of plastic consistent parameter automatically during the iterations. According to the algorithm, the nonlinear finite element program was complied and its numerical example was calculated. The numerical results indicate that this method converges very fast for both small load steps and large load steps. Compared with those results obtained by analysis and experiment, the predicted ultimate bearing capacity from the proposed method is identical.