Mahmoud Helal^1,2, Elsayed Fathallah^3,4, Abdulaziz H Alghtani¹, Hussein Shawki Osman⁵, Jong Wan Hu^6,7,*, Hasan Eleashy⁸

Intelligent Automation & Soft Computing, Vol.35, No.1, pp. 769-793, 2023, DOI:10.32604/iasc.2023.025618

Abstract To increase the payload, reduce energy consumption, improve work efficiency and therefore must accordingly reduce the total hull weight of the submersible. This paper introduces a design optimization process for the pressure-hull of submarines under uniform external hydrostatic pressure using both finite element analysis (FEA) and optimization tools. A comprehensive study about the optimum design of the pressure hull, to minimize the weight and increase the volume, to reach minimum buoyancy factor and maximum operating depth minimizing the buoyancy factor (B.F) is taken as an objective function with constraints of plate and frame yielding, general instability and deflection. The optimization… More >

J. Dujc^1,3, B. Brank^1,2, A. Ibrahimbegovic³

CMES-Computer Modeling in Engineering & Sciences, Vol.69, No.3, pp. 223-260, 2010, DOI:10.3970/cmes.2010.069.223

Abstract We present a quadrilateral finite element with discontinuous displacement fields that can be used to model material failure in 2d brittle and ductile solids. The element provides mesh-objective results. The element's kinematics can represent linear displacement jumps along the discontinuity line in both normal and tangential directions to the line. The cohesive law in the discontinuity line is based on rigid-plasticity model with softening. The material of the bulk of the element is described by hardening plasticity model. Static condensation of the jump-in-displacements kinematic parameters is made, which provides standard form of the element stiffness matrix. However, in order to… More >

Pengfei Yang¹, Yan Liu¹, Xiong Zhang^1,2, Xu Zhou³, Yuli Zhao³

CMES-Computer Modeling in Engineering & Sciences, Vol.85, No.3, pp. 207-238, 2012, DOI:10.3970/cmes.2012.085.207

Abstract The material point method is extended to the simulations of fragmentation driven by detonation. A crack modeling scheme based on contact algorithm with material failure process is developed to study the dynamic crack propagation in plastic media. When considering microscopic damage of material, the plastic behavior is described by Gurson model with randomly-distributed initial void of material points. Gurson model can degenerate to J2 plastic theory while the microscopic void is ignored, in which situation the Weibull random failure scheme will be used. Meanwhile, a background-grid-based searching method is proposed to capture the statistical feature of the fragmentation. The scaling… More >

Z. Chen^1,2, Y. Gan¹, J.K. Chen²

CMES-Computer Modeling in Engineering & Sciences, Vol.26, No.2, pp. 123-138, 2008, DOI:10.3970/cmes.2008.026.123

Abstract A coupled thermo-mechanical constitutive model with decohesion is proposed to simulate the material failure evolution due to localized heating. A discontinuous bifurcation analysis is performed based on a thermoviscoplasticity relation to identify the transition from continuous to discontinuous failure modes as well as the orientation of the discontinuous failure. The thermo-mechanical model is then implemented within the framework of the Material Point Method (MPM) so that the different gradient and divergence operators in the governing differential equations could be discretized in a single computational domain and that continuous remeshing is not required with the evolution of failure. The proposed model-based… More >