The Experts below are selected from a list of 21327 Experts worldwide ranked by ideXlab platform
Oğuzhan Hasançebi - One of the best experts on this subject based on the ideXlab platform.
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Discrete sizing optimization of steel trusses under multiple displacement constraints and Load Cases using guided stochastic search technique
Structural and Multidisciplinary Optimization, 2015Co-Authors: S. Kazemzadeh Azad, Oğuzhan HasançebiAbstract:The guided stochastic search (GSS) is a computationally efficient design optimization technique, which is originally developed for discrete sizing optimization problems of steel trusses with a Single displacement constraint under a Single Load Case. The present study aims to investigate the GSS in a more general class of truss sizing optimization problems subject to multiple displacement constraints and Load Cases. To this end, enhancements of the GSS are proposed in the form of two alternative approaches that enable the technique to deal with multiple displacement/Load Cases. The first approach implements a methodology in which the most critical displacement direction is considered only when guiding the search process. The second approach, however, takes into account the cumulative effect of all the critical displacement directions in the course of optimization. Advantage of the integrated force method of structural analysis is also utilized for further reduction of the computational effort in these approaches. The proposed enhancements of GSS are investigated and compared with some selected techniques of design optimization through six truss structures that are sized for minimum weight. The numerical results reveal that both enhancements generally provide promising solutions with an insignificant computational effort.
S. Kazemzadeh Azad - One of the best experts on this subject based on the ideXlab platform.
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Discrete sizing optimization of steel trusses under multiple displacement constraints and Load Cases using guided stochastic search technique
Structural and Multidisciplinary Optimization, 2015Co-Authors: S. Kazemzadeh Azad, Oğuzhan HasançebiAbstract:The guided stochastic search (GSS) is a computationally efficient design optimization technique, which is originally developed for discrete sizing optimization problems of steel trusses with a Single displacement constraint under a Single Load Case. The present study aims to investigate the GSS in a more general class of truss sizing optimization problems subject to multiple displacement constraints and Load Cases. To this end, enhancements of the GSS are proposed in the form of two alternative approaches that enable the technique to deal with multiple displacement/Load Cases. The first approach implements a methodology in which the most critical displacement direction is considered only when guiding the search process. The second approach, however, takes into account the cumulative effect of all the critical displacement directions in the course of optimization. Advantage of the integrated force method of structural analysis is also utilized for further reduction of the computational effort in these approaches. The proposed enhancements of GSS are investigated and compared with some selected techniques of design optimization through six truss structures that are sized for minimum weight. The numerical results reveal that both enhancements generally provide promising solutions with an insignificant computational effort.
Tomasz Lewinski - One of the best experts on this subject based on the ideXlab platform.
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on material design by the optimal choice of young s modulus distribution
International Journal of Solids and Structures, 2017Co-Authors: S. Czarnecki, Tomasz LewinskiAbstract:Abstract This paper concerns the problem of optimal distribution of Young's modulus within an elastic and isotropic body with prescribed, not necessarily uniform, distribution of Poisson's ratio. The merit function is the total compliance corresponding to a given Single Load Case. The unit cost of the design is assumed as the trace of Hooke's tensor, which is proportional to Young's modulus here. The problem thus formulated is a constrained version of the isotropic material design problem, in which both bulk and shear elastic moduli of isotropy are design variables. In contrast to the latter approach, the optimal material is either nonsingular or degenerates to a void. The optimal distribution of Young's modulus is determined by a solution to an auxiliary minimization problem with the integrand of linear growth. The problem dual to the latter assumes the form similar to that known from the theory of Michell trusses. The proposed numerical approach focuses on solving the former auxiliary problem. The Case studies comprise selected optimal designs corresponding to the isotropic material optimization and Young's modulus optimization developed in this paper. The exemplary optimal solutions show that admitting negative values of Poisson's ratio may contribute to a decrease of the total compliance, thus leading to better designs.
Jordan, Ashante L. - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of Wing Load Calibration and Sensing Methods Using Conventional Strain Gages and a Fiber Optic Sensing System Installed on a Straight Tapered Wing
2019Co-Authors: Lokos, William A., Hudson, Larry D., Pena Francisco, Miller, Eric J., Jordan, Ashante L.Abstract:State-of-the-art instrumentation techniques have provided an opportunity to obtain greater insight into structural wing Loads during flight. An investigation was undertaken to research new wing instrumentation and Load sensing techniques for measuring accurate in-flight spanwise Load distributions on wing structures. A straight tapered wing was instrumented with both conventional foil strain gages at five spanwise wing stations and fiber optic strain sensors at every half inch along the entire wing span. Thirty-nine unique Load Cases were applied to the wing lower surface using hydraulic actuators to obtain various shear, bending moment, and torque Load distributions on the wing. This paper will highlight three Load calibration approaches. Conventional linear regression calibration methods were applied to foil strain gages providing a Single wing station vertical shear, bending moment, and torque Load. Linear regression methods were applied to a fiber optic sensing system to provide bending moment and torque spanwise Load distributions. A Load sensing scheme using strain derived wing shape information derived from a Single Load Case provided vertical shear and bending moment spanwise Load distribution information. Aspects of the three different approaches will be compared and contrasted to inform the reader of the benefits or disadvantages of each. Instrument installation, sensor characteristics, test execution aspects, and recommended calibration techniques will be discussed
S. Czarnecki - One of the best experts on this subject based on the ideXlab platform.
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on material design by the optimal choice of young s modulus distribution
International Journal of Solids and Structures, 2017Co-Authors: S. Czarnecki, Tomasz LewinskiAbstract:Abstract This paper concerns the problem of optimal distribution of Young's modulus within an elastic and isotropic body with prescribed, not necessarily uniform, distribution of Poisson's ratio. The merit function is the total compliance corresponding to a given Single Load Case. The unit cost of the design is assumed as the trace of Hooke's tensor, which is proportional to Young's modulus here. The problem thus formulated is a constrained version of the isotropic material design problem, in which both bulk and shear elastic moduli of isotropy are design variables. In contrast to the latter approach, the optimal material is either nonsingular or degenerates to a void. The optimal distribution of Young's modulus is determined by a solution to an auxiliary minimization problem with the integrand of linear growth. The problem dual to the latter assumes the form similar to that known from the theory of Michell trusses. The proposed numerical approach focuses on solving the former auxiliary problem. The Case studies comprise selected optimal designs corresponding to the isotropic material optimization and Young's modulus optimization developed in this paper. The exemplary optimal solutions show that admitting negative values of Poisson's ratio may contribute to a decrease of the total compliance, thus leading to better designs.