A Three-Scale Fuzzy Analytical Hierarchy Process (T-FAHP) is proposed by introducing the Three-Scale Analytical Hierarchy Process (T-AHP) and the trapezoid fuzzy number. A multi-objective optimization model based on t...A Three-Scale Fuzzy Analytical Hierarchy Process (T-FAHP) is proposed by introducing the Three-Scale Analytical Hierarchy Process (T-AHP) and the trapezoid fuzzy number. A multi-objective optimization model based on the T-FAHP is presented subsequently, in which many factors influencing the lectotype of offshore platform are taken into account synthetically, such as the original investment, the maintenance, cost, the ability of resisting fatigue and corrosion, the construction period, the threat to the environment, and so on. With this method, the experts can give the relatively precise ranking weight of each index and at the same time the requirement of consistence checking can be met, The result of a calculation example shows that the T-FAHP is practical.展开更多
A new microelement method for the analyses of functionally graded structures was proposed. The key of this method is the maneuverable combination of two kinds of elements. Firstly, the macro elements are divided from ...A new microelement method for the analyses of functionally graded structures was proposed. The key of this method is the maneuverable combination of two kinds of elements. Firstly, the macro elements are divided from the functionally graded material structures by the normal finite elements. In order to reflect the functionally graded distributions of materials and the microconstitutions in each macro-element, the microelement method sets up the dense microelements in every macro-element, and translates nodes to the same as the normal finite elements by the degrees of freedom of all microelemental the compatibility conditions. This microelement method can fully reflect the micro constitutions and different components of materials, and its computational elements are the same as the normal finite elements, so it is an effective numerical method for the analyses of the functionally graded material structures. The three-dimensional analyses of functionally graded plates with medium components and different micro net structures are given by using the microelement method in this paper. The differences of the stress contour in the plane of functionally graded plates with different net microstructures are especially given in this paper.展开更多
在细观结构层次上将大坝混凝土作为骨料、固化水泥砂浆及其粘结界面组成的复合材料,建立了大坝混凝土三维细观力学数值模型。该模型既能够反映混凝土及其细观各相材料在荷载作用下的损伤演化过程,又考虑了动载作用的应变率强化效应。给...在细观结构层次上将大坝混凝土作为骨料、固化水泥砂浆及其粘结界面组成的复合材料,建立了大坝混凝土三维细观力学数值模型。该模型既能够反映混凝土及其细观各相材料在荷载作用下的损伤演化过程,又考虑了动载作用的应变率强化效应。给出了该数值模型求解方法,并编制出能够在普通PC机上运行的串行程序。加载过程既可按荷载控制又可按位移控制。同时,为了减少求解自由度应用了分尺度方法以使最小骨料和固化水泥砂浆混合后其力学性能与一种复合介质等效。通过混凝土湿筛和三级配试件的静、动(冲击)弯拉数值计算验证了本文计算方法和程序正确有效。另外,在串行程序的基础上,优化了刚度矩阵的存储方式,采用双门槛不完全Cholesky分解(ICT)预条件的共轭梯度法(CG),完成了能够在Sun Fire 6800服务器实现并行计算的并行程序改造,从而大大提高了计算效率。展开更多
基金This work was financially supported by the National Natural Science Foundation of China(Grant No.59895410)
文摘A Three-Scale Fuzzy Analytical Hierarchy Process (T-FAHP) is proposed by introducing the Three-Scale Analytical Hierarchy Process (T-AHP) and the trapezoid fuzzy number. A multi-objective optimization model based on the T-FAHP is presented subsequently, in which many factors influencing the lectotype of offshore platform are taken into account synthetically, such as the original investment, the maintenance, cost, the ability of resisting fatigue and corrosion, the construction period, the threat to the environment, and so on. With this method, the experts can give the relatively precise ranking weight of each index and at the same time the requirement of consistence checking can be met, The result of a calculation example shows that the T-FAHP is practical.
基金supported by the National Natural Science Foundation of China (No.10432030)the National Youth Science Foundation of China (No.10802091)the Scientific and Technical Foundation of China University of Mining and Technology (No.2007B013)
文摘A new microelement method for the analyses of functionally graded structures was proposed. The key of this method is the maneuverable combination of two kinds of elements. Firstly, the macro elements are divided from the functionally graded material structures by the normal finite elements. In order to reflect the functionally graded distributions of materials and the microconstitutions in each macro-element, the microelement method sets up the dense microelements in every macro-element, and translates nodes to the same as the normal finite elements by the degrees of freedom of all microelemental the compatibility conditions. This microelement method can fully reflect the micro constitutions and different components of materials, and its computational elements are the same as the normal finite elements, so it is an effective numerical method for the analyses of the functionally graded material structures. The three-dimensional analyses of functionally graded plates with medium components and different micro net structures are given by using the microelement method in this paper. The differences of the stress contour in the plane of functionally graded plates with different net microstructures are especially given in this paper.
文摘在细观结构层次上将大坝混凝土作为骨料、固化水泥砂浆及其粘结界面组成的复合材料,建立了大坝混凝土三维细观力学数值模型。该模型既能够反映混凝土及其细观各相材料在荷载作用下的损伤演化过程,又考虑了动载作用的应变率强化效应。给出了该数值模型求解方法,并编制出能够在普通PC机上运行的串行程序。加载过程既可按荷载控制又可按位移控制。同时,为了减少求解自由度应用了分尺度方法以使最小骨料和固化水泥砂浆混合后其力学性能与一种复合介质等效。通过混凝土湿筛和三级配试件的静、动(冲击)弯拉数值计算验证了本文计算方法和程序正确有效。另外,在串行程序的基础上,优化了刚度矩阵的存储方式,采用双门槛不完全Cholesky分解(ICT)预条件的共轭梯度法(CG),完成了能够在Sun Fire 6800服务器实现并行计算的并行程序改造,从而大大提高了计算效率。
