This paper presents a multi-objective topology optimization method for the temperature field considering the material nonlinearities. Although a large number of papers have studied the topology optimizations of the heat transfer problems, none of them considered the influence of the material nonlinearity properties. In this paper, the material nonlinearity is considered. Based on the nonlinear assumption, the mathematical model of the corresponding topology optimization is presented first. Then, the sensitivities of the objectives and the constraints respect to the design variables are derived. And the optimization routines are discussed. After establishing the theories and solving scheme, a software is developed by MATLAB for the topology design of the nonlinear heat transfer. Several nonlinear numerical examples are presented. And the corresponding optimal results generated under the linear assuming are also collected for comparisons. Furthermore, this paper also simply discusses the preventing approaches of instabilities and the implementation methods of some other unusual engineering constraints. These true engineering considerations are very helpful for the real industry design experiences.
The existing model for calculating the settlements of group piles is based on the principle of superposition, which fails to calculate the interaction between piles more comprehensively and to take into consideration the influence of slip between pile and soil. In this paper, the interaction between group piles is analyzed from a novel perspective. It is assumed that the interaction between piles is a dynamic equilibrium process, i.e., additional shear forces and additional displacements are continuously transferred between piles until a state of equilibrium is reached. On this basis, we propose a new model for calculating the settlements of group piles considering pile–soil slip. First, a calculation method for pile–side resistance is developed considering the influence of slip. Based on experience with the pile–soil interface, pile–side soils can be categorized as near–pile soil and far–pile soil, and different load–transfer models are applied to describe their mechanical states. By equating pile–side soils into a nonlinear spring and connecting them in series to determine the overall equivalent stiffness considering the effect of pile–soil slip, the pile–side resistance under different loading conditions can be accurately determined. Secondly, equilibrium analysis of the pile unit is carried out when the equilibrium condition is reached, and the stiffness matrix for load transfer is derived. Therefore, in this paper, the interaction between piles is concentrated in this matrix, which makes the proposed model for pile settlement calculation clearer and more concise. Compared with measured data, the proposed method can capture the main features of the load–settlement behavior of group piles.
In this paper, the electro-hydraulic control valve commonly used in ships is taken as the research object, the working principle of the valve is introduced, the model of the valve is established by AMESim software, the model parameters are set and the simulation analysis is carried out. By changing the relevant parameters of the valve, the response speed of the valve can be improved. The simulation results show that the pressure area of load sensitive cavity and the diameter of damping hole have obvious influence on the response speed of valve.
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