The optimality criteria （OC） method and mathematical programming （MP） were combined to found the sectional optimization model of frame structures. Different methods were adopted to deal with the different constrai...The optimality criteria （OC） method and mathematical programming （MP） were combined to found the sectional optimization model of frame structures. Different methods were adopted to deal with the different constraints. The stress constraints as local constraints were approached by zero-order approximation and transformed into movable sectional lower limits with the full stress criterion. The displacement constraints as global constraints were transformed into explicit expressions with the unit virtual load method. Thus an approximate explicit model for the sectional optimization of frame structures was built with stress and displacement constraints. To improve the resolution efficiency, the dual-quadratic programming was adopted to transform the original optimization model into a dual problem according to the dual theory and solved iteratively in its dual space. A method called approximate scaling step was adopted to reduce computations and smooth the iterative process. Negative constraints were deleted to reduce the size of the optimization model. With MSC/Nastran software as structural solver and MSC/Patran software as developing platform, the sectional optimization software of frame structures was accomplished, considering stress and displacement constraints. The examples show that the efficiency and accuracy are improved.展开更多
This paper deals with the concurrent multi-scale optimization design of frame structure composed of glass or carbon fiber reinforced polymer laminates. In the composite frame structure, the fiber winding angle at the ...This paper deals with the concurrent multi-scale optimization design of frame structure composed of glass or carbon fiber reinforced polymer laminates. In the composite frame structure, the fiber winding angle at the micro-material scale and the geometrical parameter of components of the frame in the macro-structural scale are introduced as the independent variables on the two geometrical scales. Considering manufacturing requirements, discrete fiber winding angles are specified for the micro design variable. The improved Heaviside penalization discrete material optimization interpolation scheme has been applied to achieve the discrete optimization design of the fiber winding angle. An optimization model based on the minimum structural compliance and the specified fiber material volume constraint has been established. The sensitivity information about the two geometrical scales design variables are also deduced considering the characteristics of discrete fiber winding angles. The optimization results of the fiber winding angle or the macro structural topology on the two single geometrical scales, together with the concurrent two-scale optimization, is separately studied and compared in the paper. Numerical examples in the paper show that the concurrent multi-scale optimization can further explore the coupling effect between the macro-structure and micro-material of the composite to achieve an ultralight design of the composite frame structure. The novel two geometrical scales optimization model provides a new opportunity for the design of composite structure in aerospace and other industries.展开更多
In order to obtain a deeper understanding of the behavior of the structure under high wind load,this paper conducted an experimental study on a full-scale L-shaped single story light frame wood house under the uniform...In order to obtain a deeper understanding of the behavior of the structure under high wind load,this paper conducted an experimental study on a full-scale L-shaped single story light frame wood house under the uniform lateral load simulated using a gasbag.The investigation involved the performance of light frame wood structure after it experienced the repeated cyclic lateral wind load as well as the performance of the structure under the ultimate lateral load.Then,the study verified that light frame wood structure can resist repeated cyclic wind loads without observable degradation in stiffness during the anticipated serve life,and recommended shear wall percent drift restriction for lateral wind load design of wood structure in serviceability limit states is 1/400 drift,and in ultimate limit states is 1/80 drift.The conclusions of this paper can be benefit for the engineering practice of the light frame wood structures in high wind load regions.展开更多
In order to clear constructional design of corner joint, it is necessary to further investi-gate mechanical property of corner joint in gabled frames. Through static test and finite element software analysis of compar...In order to clear constructional design of corner joint, it is necessary to further investi-gate mechanical property of corner joint in gabled frames. Through static test and finite element software analysis of comparing the panel zone with and without inclined stiffener. Some conclusions are given in the article. The load displacement curves show that the capacity of oblique nodes installed within stiffening rib components is enhanced i.e. 40% more than those without stiffening rib nodes. The results reveal that in the gabled frames, the corner node with the inclined stiffening rib can improve the bearing capacity of the specimens. When the extraterritorial flange is tension, the erection of the inclined stiffening rib can prevent structural failure and improve effectually the ductility of the structure.展开更多
基金Project supported by the National Natural Science Foundation of China(No. 10472003) the Natural Science Foundation of Beijing(No.3002002) the Science Foundation of Beijing Municipal Commission of Education(No.KM200410005019)
文摘The optimality criteria （OC） method and mathematical programming （MP） were combined to found the sectional optimization model of frame structures. Different methods were adopted to deal with the different constraints. The stress constraints as local constraints were approached by zero-order approximation and transformed into movable sectional lower limits with the full stress criterion. The displacement constraints as global constraints were transformed into explicit expressions with the unit virtual load method. Thus an approximate explicit model for the sectional optimization of frame structures was built with stress and displacement constraints. To improve the resolution efficiency, the dual-quadratic programming was adopted to transform the original optimization model into a dual problem according to the dual theory and solved iteratively in its dual space. A method called approximate scaling step was adopted to reduce computations and smooth the iterative process. Negative constraints were deleted to reduce the size of the optimization model. With MSC/Nastran software as structural solver and MSC/Patran software as developing platform, the sectional optimization software of frame structures was accomplished, considering stress and displacement constraints. The examples show that the efficiency and accuracy are improved.
基金financial support for this research was provided by the Program (Grants 11372060, 91216201) of the National Natural Science Foundation of ChinaProgram (LJQ2015026 ) for Excellent Talents at Colleges and Universities in Liaoning Province+3 种基金the Major National Science and Technology Project (2011ZX02403-002)111 project (B14013)Fundamental Research Funds for the Central Universities (DUT14LK30)the China Scholarship Fund
文摘This paper deals with the concurrent multi-scale optimization design of frame structure composed of glass or carbon fiber reinforced polymer laminates. In the composite frame structure, the fiber winding angle at the micro-material scale and the geometrical parameter of components of the frame in the macro-structural scale are introduced as the independent variables on the two geometrical scales. Considering manufacturing requirements, discrete fiber winding angles are specified for the micro design variable. The improved Heaviside penalization discrete material optimization interpolation scheme has been applied to achieve the discrete optimization design of the fiber winding angle. An optimization model based on the minimum structural compliance and the specified fiber material volume constraint has been established. The sensitivity information about the two geometrical scales design variables are also deduced considering the characteristics of discrete fiber winding angles. The optimization results of the fiber winding angle or the macro structural topology on the two single geometrical scales, together with the concurrent two-scale optimization, is separately studied and compared in the paper. Numerical examples in the paper show that the concurrent multi-scale optimization can further explore the coupling effect between the macro-structure and micro-material of the composite to achieve an ultralight design of the composite frame structure. The novel two geometrical scales optimization model provides a new opportunity for the design of composite structure in aerospace and other industries.
基金Sponsored by the National Natural Science Foundation of China(Grant No. 50508012)
文摘In order to obtain a deeper understanding of the behavior of the structure under high wind load,this paper conducted an experimental study on a full-scale L-shaped single story light frame wood house under the uniform lateral load simulated using a gasbag.The investigation involved the performance of light frame wood structure after it experienced the repeated cyclic lateral wind load as well as the performance of the structure under the ultimate lateral load.Then,the study verified that light frame wood structure can resist repeated cyclic wind loads without observable degradation in stiffness during the anticipated serve life,and recommended shear wall percent drift restriction for lateral wind load design of wood structure in serviceability limit states is 1/400 drift,and in ultimate limit states is 1/80 drift.The conclusions of this paper can be benefit for the engineering practice of the light frame wood structures in high wind load regions.
文摘In order to clear constructional design of corner joint, it is necessary to further investi-gate mechanical property of corner joint in gabled frames. Through static test and finite element software analysis of comparing the panel zone with and without inclined stiffener. Some conclusions are given in the article. The load displacement curves show that the capacity of oblique nodes installed within stiffening rib components is enhanced i.e. 40% more than those without stiffening rib nodes. The results reveal that in the gabled frames, the corner node with the inclined stiffening rib can improve the bearing capacity of the specimens. When the extraterritorial flange is tension, the erection of the inclined stiffening rib can prevent structural failure and improve effectually the ductility of the structure.
