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An extended finite element method for modeling elastoplastic FGM plate-shell type structures
Jrad, Hanen,Mars, Jamel,Wali, Mondher,Dammak, Fakhreddine Techno-Press 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.68 No.3
In this paper, an extended finite element method is proposed to analyze both geometric and material non-linear behavior of general Functionally Graded Material (FGM) plate-shell type structures. A user defined subroutine (UMAT) is developed and implemented in Abaqus/Standard to study the elastoplastic behavior of the ceramic particle-reinforced metal-matrix FGM plates-shells. The standard quadrilateral 4-nodes shell element with three rotational and three translational degrees of freedom per node, S4, is extended in the present study, to deal with elasto-plastic analysis of geometrically non-linear FGM plate-shell structures. The elastoplastic material properties are assumed to vary smoothly through the thickness of the plate-shell type structures. The nonlinear approach is based on Mori-Tanaka model to underline micromechanics and locally determine the effective FGM properties and self-consistent method of Suquet for the homogenization of the stress-field. The elasto-plastic behavior of the ceramic/metal FGM is assumed to follow Ludwik hardening law. An incremental formulation of the elasto-plastic constitutive relation is developed to predict the tangent operator. In order to to highlight the effectiveness and the accuracy of the present finite element procedure, numerical examples of geometrically non-linear elastoplastic functionally graded plates and shells are presented. The effects of the geometrical parameters and the volume fraction index on nonlinear responses are performed.
An extended finite element method for modeling elastoplastic FGM plate-shell type structures
Hanen Jrad,Jamel Mars,Mondher Wali,Fakhreddine Dammak 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.68 No.3
In this paper, an extended finite element method is proposed to analyze both geometric and material non-linear behavior of general Functionally Graded Material (FGM) plate-shell type structures. A user defined subroutine (UMAT) is developed and implemented in Abaqus/Standard to study the elastoplastic behavior of the ceramic particle-reinforced metal-matrix FGM plates-shells. The standard quadrilateral 4-nodes shell element with three rotational and three translational degrees of freedom per node, S4, is extended in the present study, to deal with elasto-plastic analysis of geometrically non-linear FGM plate-shell structures. The elastoplastic material properties are assumed to vary smoothly through the thickness of the plate-shell type structures. The nonlinear approach is based on Mori-Tanaka model to underline micromechanics and locally determine the effective FGM properties and self-consistent method of Suquet for the homogenization of the stress-field. The elasto-plastic behavior of the ceramic/metal FGM is assumed to follow Ludwik hardening law. An incremental formulation of the elasto-plastic constitutive relation is developed to predict the tangent operator. In order to to highlight the effectiveness and the accuracy of the present finite element procedure, numerical examples of geometrically non-linear elastoplastic functionally graded plates and shells are presented. The effects of the geometrical parameters and the volume fraction index on nonlinear responses are performed.
Hana Mellouli,Hanen Jrad,Monther Wali,Fakhreddine Dammak 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.31 No.4
In this paper, a geometrically nonlinear meshfree analysis of 3D various forms of shell structures using the double director shell theory with finite rotations is proposed. This theory is introduced in the present method to remove the shear correction factor and to improve the accuracy of transverse shear stresses with the consideration of rotational degrees of freedom.The present meshfree method is based on the radial point interpolation method (RPIM) which is employed for the construction of shape functions for a set of nodes distributed in a problem domain. Discrete system of geometrically nonlinear equilibrium equations solved with the Newton-Raphson method is obtained by incorporating these interpolations into the weak form. The accuracy of the proposed method is examined by comparing the present results with the accurate ones available in the literature and good agreements are found.
Mechanical Behavior of Embossed AA1050-O Sheets Subjected to Tension and Forming
사비르므졸리,Carl Labergere,Marion Martiny,Mohamad Jrad,Guillaume Robin,김흥수,Francois Choquart 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.19 No.10
In this paper, experimental characterization of embossed aluminum sheets is performed using extensive mechanical tests. Rotary embossing is performed on these sheets in order to obtain a periodic hill-and-valley structure. The experimental program consists of realizing mechanical tests such as tension, deep drawing, and hydraulic bulge tests using embossed samples in order to build a database that can be used for future finite element modeling tasks. The tensile tests are performed using digital images correlation (DIC) for total displacement measurements and for detailed strain maps. The hydraulic bulge and deep drawing tests are conducted on embossed circular samples to study their formability. A comparison was made with the plane (non-embossed) sheets to explain the contribution of the embossed structure either in both cases of uniaxial and multiaxial loadings.
Raghunath, Chaitra,Watson, Layne T.,Jrad, Mohamed,Kapania, Rakesh K.,Kolonay, Raymond M. Techno-Press 2017 Advances in aircraft and spacecraft science Vol.4 No.3
With rapid growth in the complexity of large scale engineering systems, the application of multidisciplinary analysis and design optimization (MDO) in the engineering design process has garnered much attention. MDO addresses the challenge of integrating several different disciplines into the design process. Primary challenges of MDO include computational expense and poor scalability. The introduction of a distributed, collaborative computational environment results in better utilization of available computational resources, reducing the time to solution, and enhancing scalability. SORCER, a Java-based network-centric computing platform, enables analyses and design studies in a distributed collaborative computing environment. Two different optimization algorithms widely used in multidisciplinary engineering design-VTDIRECT95 and QNSTOP-are implemented on a SORCER grid. VTDIRECT95, a Fortran 95 implementation of D. R. Jones' algorithm DIRECT, is a highly parallelizable derivative-free deterministic global optimization algorithm. QNSTOP is a parallel quasi-Newton algorithm for stochastic optimization problems. The purpose of integrating VTDIRECT95 and QNSTOP into the SORCER framework is to provide load balancing among computational resources, resulting in a dynamically scalable process. Further, the federated computing paradigm implemented by SORCER manages distributed services in real time, thereby significantly speeding up the design process. Part 1 covers SORCER and the algorithms, Part 2 presents results for aircraft panel design with curvilinear stiffeners.