共查询到20条相似文献,搜索用时 15 毫秒
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In this work we investigate the material behaviour of steel 51CrV4 in classical uniaxial strain controlled tension tests of different strain rates interposed by relaxation steps, in which the equilibrium stress observed is significantly smaller than the stresses seen in slowest strain rate test. Also, some cyclic experiments with different strain rates and amplitudes were done to analyze the hysteresis behaviour of the material. Against this background of experimental data the modeling possibilties of two models are explored: the Lion model and the Chaboche model with kinematic hardening ansatz. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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A modelling approach is described using the modules vehicle body, front axle and rear axle. All these modules are virtually assembled by CAD software and Simpack, a commercial multibody dynamics tool. The geometrical data are found from the CAD model while the mechanical data for the entire vehicle are evaluated by parameter identification based on mechanical principles. In detail, the static measurement and error analysis of the center of mass is explained as well as the dynamic tests to identify the moments of inertia of the car. Further, spring and damper characteristics are identified. (© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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In the present article we discuss the characterization of the mechanical properties of long fiber reinforced thermoplastics (LFT) and sheet molding compounds (SMC) with biaxial tensile tests and the inverse parameter identification. The full 3D strain field is measured via digital image correlation (DIC). The anisotropic viscoelastic material properties are identified through inverse modelling by comparison of the heterogeneous experimental and simulated strain fields. A Gauss-Newton type algorithm is used to identify the optimal parameter set [1]. (© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Glasfibre structures feature high potentials for optimization and substitution of conventional materials like steel and aluminum and their alloys. The paper deals with the insertion of glasfibre trusses into thin glasfibre structures to reinforce them. The effective material properties of the glasfibre structures were estimated by experiments and simulations. Furthermore the Young's modulus of the trusses was obtained by bending tests and tension tests. A comparison between bending experiments and bending simulations is given. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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A finite deformation framework for nonlinear magneto-viscoelasticity is introduced and applied to the constitutive and structural modeling of magnetoactive polymer (MAP) response. In this thermodynamically-consistent formulation the free energy function consists of purely elastic, purely magnetic and coupling contributions, where the rate-dependence is fully attributed to the non-magnetizable matrix material. The model consistently accounts for saturation in the magnetic as well as the magnetostrictive behavior. The identification of material parameters from experimental data is briefly described. Finally, a finite element model for the large strain magneto-mechanical problem is established and tested considering MAP behavior. (© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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V. N. Chetverikov 《Differential Equations》2018,54(11):1524-1534
The problem of continuation of an input-output mapping to a right invertible mapping is solved. The proposed solution is based on transforming the system to a normal form and solving the problem for such systems. The well-known Singh inversion algorithm is modified to calculate the normal forms. It is proved that each step of the modified algorithm can be realized and the result of the algorithm application is a normal form. A new approach to the parameter identification problem based on the inversion of the input-output mapping is proposed to illustrate the application of the results. 相似文献
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考虑了辨识下列方程中算子值参数B的必要条件,代价泛函为:证明了:最佳估计B0由一个优化系统确定,而该优化系统由状态方程、伴随方程和优化条件组成. 相似文献
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变压器温度场参数辨识问题是一种分片光滑的分布参数辨识问题,以流速为辨识参数,针对传质传热的一类分布参数系统参数辨识问题,证明了系统最优参数的存在性和控制参数为最优的必要条件,为变压器温度场的数值模拟研究提供了理论基础. 相似文献
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Prestrained shape memory alloys change their length when heated above their transformation temperature. This effect can be used to generate high forces in a small workspace, which has particular advantages in actuator design. The optimization and control of the shape memory actuator requires a comprehensive simulation of the material behavior. However, many of the existing models are limited to specific load cases or offer rough approximations only. A material model for shape memory alloys from Seelecke [1] is examined in this paper. This model describes the behavior of a shape memory wire, which is heated by electric current. It is implemented in a simulation program to investigate the actuator output and to improve the performance. Finally, the parameters of the simulation are adapted to experimental results. 相似文献
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During stress-induced transformation NiTi shows a distinct generation of transformation bands. A simple one-dimensional model for superelastic NiTi wires has been developed to show exemplarily methods to account for these bands in plasticitybased models. To clarify the dependence of the transformation bands on the distribution of latent heat and therefore on the mechanical behaviour, optical and thermographical experiments have been performed. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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B.C. Fabien M. Ramulu M. Tremblay 《Mathematical and Computer Modelling of Dynamical Systems: Methods, Tools and Applications in Engineering and Related Sciences》2013,19(1):45-63
This paper describes a new dynamic model for a waterjet cutting system that includes a double-acting reciprocating intensifier pump. Since the system operates at high pressures the fluid flow is assumed to be compressible. The dynamic model includes the characteristics of the intensifier pump, the check valves, the accumulator, the system piping and compressible jet flow through the nozzle. The system model is presented as a set of differential-algebraic equations. Experimental results for an actual system are used to identify the discharge coefficient of the nozzle, certain unknown parameters associated with the check valve, and to determine the velocity profile of the piston in the intensifier pump. This is accomplished by formulating and solving a parameter optimization problem. The paper also includes numerical simulation results that validate the dynamic model. 相似文献
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This work is concerned with the identification of material parameters for isotropic, incompressible hyperelastic material models. Besides the principal stretch-based strain-energy function by Ogden an invariant-based strain-energy function by Rivlin/Saunders is considered for which parameter sensitivities are derived. The identification is formulated as a least-squares minimization problem based on the finite element method to account for inhomogeneous states of stresses and strains in the experimental data which is obtained by optical measurements. For the finite element method low-order tetrahedral elements in a mixed displacement-pressure formulation with stabilization are considered. Special attention is payed to an adaptive mesh-refinement based on a goal-oriented a posteriori error indicator to gain reliable material parameters. To approximate error terms an element-wise recovery technique based on enhanced gradients is introduced. (© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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该文考虑抑制剂作用下肿瘤生长的模型. 假设肿瘤是球对称的, 其表面为运动边界, 用函数r=R(t)表示. 既然多细胞肿瘤扁球体(MTS)通常作为肿瘤生长的体外模型, 在实验室能够被观察和控制, 因此研究如下反问题: 根据观察到的MTS动态增长(即给定R(t)), 来确定抑制剂的参数. 运用极大值原理, 作者证明了该抛物反问题解的唯一性. 进一步, 用最优控制框架来重构模型中的抑制剂参数, 证明了最优控制问题解的存在性, 并推导了最优控制满足的最优性必要条件. 相似文献
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Parameter identification processes concern the determination of parameters in a material model in order to fit experimental data. We provide a distinct, unified algorithmic setting of a generic class of material models and discuss the associated gradient–based optimization problem. Gradient–based optimization algorithms need derivatives of the objective function with respect to the material parameter vector κ . In order to obtain the necessary derivatives, an analytical sensitivity analysis is pointed out for the unified class of algorithmic material models. The quality of the parameter identification is demonstrated for a representative example. 相似文献
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基于GPEM主旋律分析的系统序参量识别方法研究 总被引:2,自引:0,他引:2
针对系统的演化与发展,引入基于目标规划评价模型(GPEM)的主旋律分析方法,识别引导与支配系统发展的序参量.通过分析主旋律与序参量间的关系,认为在GPEM中的价值参数结构是二者的共同体现,且主旋律分析是序参量识别的前提与基础.应用基于GPEM的主旋律分析方法对系统所属群体进行相关计算,可以获得群体发展的主旋律,同时可以获得群体成员在各主旋律下的排名向量,进而认为与理想排名向量相似系数最高的主旋律在群体发展过程中发挥着关键性作用,则该主旋律对应的价值参数结构即为序参量.通过观察该主旋律所集聚成员在理想排名向量中的位置,来判断与分析序参量的特征. 相似文献