Papers by Keyword: Nonlinear Structure

Abstract: To enhance the efficiency for the shape optimization of complex nonlinear structure, based on the FE analysis combined with the sensitivity analysis, the gradient-based Kriging (GBK) method is applied. A new criterion to determine the likely best spatial correlation parameter in GBK based on Latin Hypercube Design (LHD) presented by authors is also applied. A more practical example for the shape optimization of automotive tire is presented to show the applicability of the GBK method.

Abstract: Identification of nonlinear behavior in structural dynamics has been considered here, in this paper. Time domain output data of system are directly used to identify system through Ibrahim Time Domain (ITD) modal analysis method and perturbed eigen problem. Cubic stiffness and Jenkins element, as case studies, are employed to qualify the identification method. Results are compared with Harmonic Balance (HB) estimation of nonlinear dynamic stiffness. Results of ITD based identification are in good agreement with the HB estimation, for stiffness parts of nonlinear dynamic stiffness but for damping parts of nonlinear dynamic stiffness, method needs some additional improvements which are under investigation.

Abstract: Recently, detection of structural damage based on the system identification has received great attention. In this paper, a technique is proposed for the identification of nonlinear structural parameters under unmeasured excitation. The identification algorithm is based on the extended Kalman filter for the extended state vectors including nonlinear parameters and the recursive least squares estimation for the unknown inputs. Two different models are used to simulate nonlinear structures: One is a 4-storey Duffing-type nonlinear elastic shear-frame structure, the other is a 4-storey Bouc-Wen hysteretic shear-frame structure.Two numerical examples are carried out on the two kinds of models. The simulation results demonstrate that the proposed approach is capable of identifying the nonlinear structural parameters and unknown inputs with good accuracy.

Abstract: The Self-propagating High-temperature Synthesis(SHS) process is a nonlinear one far from thermodynamic equilibrium, many nonlinear structures present in the process. After SHS processes of Ti-C-Fe and Ni-Si systems have been studied by the numbers, the effects of initial parameter conditions on nonlinear structure have been gained. On the base of establishing the model of combustion reaction dynamic characteristics, backward finite-difference approximation equations and central finite-difference approximation equations were applied to numerically calculate and simulate the characteristics of combustion wave and its’ change rules in the SHS process. All the experimental results are consistent with the simulative results.