It is known that structural optimization may lead to designs of structures having low stability and sometimes even kinematically unstable designs. This paper presents a robust design method for improving the stability...It is known that structural optimization may lead to designs of structures having low stability and sometimes even kinematically unstable designs. This paper presents a robust design method for improving the stability of opti mized structures. A new approach is proposed, in which cer tain perturbation loads are introduced and the corresponding compliance is added to the objective function as a penaliza tion. The stability of the optimized structures can thus be improved substantially by considering structural responses to the original and the introduced loads. Numerical exam ples show the simplicity and effectiveness of the proposed method.展开更多
In this paper,the nonlinear dynamic behaviors of a hyperelastic cylindrical membrane composed of the incompressible Ogden material are examined,where the membrane is subjected to uniformly distributed radial periodic ...In this paper,the nonlinear dynamic behaviors of a hyperelastic cylindrical membrane composed of the incompressible Ogden material are examined,where the membrane is subjected to uniformly distributed radial periodic loads at the internal surface and surrounded by a thermal field.A second-order nonlinear differential equation describing the radially symmetric motion of the membrane is obtained.Then,the dynamic characteristics of the system are qualitatively analyzed in terms of different material parameter spaces and ambient tem-peratures.Particularly,for a given constant load,the bifurcation phenomenon of equilibrium points is examined.It is shown that there exists a critical load,and the phase orbits may be the asymmetrie homoclinic orbits of the“oo”type.Moreover,for the system with two centers and one saddle point,the dynamic behaviors of the system show softening phenomena at both centers,but the temperature has opposite effects on the stiffness of the structure.For a given periodically perturbed load superposed on the constant term,some complex dynamic behaviors such as quasiperiodic and chaotic oscillations are analyzed.With the Poincare section and the maximum Lyapunov characteristic exponent,it is found that the ambient temperature could lead to the irregularity and unpredictability of the nonlinear system,and also changes the threshold of chaos.展开更多
基金supported by State Key Laboratory of Structural Analysis for Industrial Equipment,Dalian University of Technology,China(GZ1305)the National Natural Science Foundation of China(11002058 and 11372004)
文摘It is known that structural optimization may lead to designs of structures having low stability and sometimes even kinematically unstable designs. This paper presents a robust design method for improving the stability of opti mized structures. A new approach is proposed, in which cer tain perturbation loads are introduced and the corresponding compliance is added to the objective function as a penaliza tion. The stability of the optimized structures can thus be improved substantially by considering structural responses to the original and the introduced loads. Numerical exam ples show the simplicity and effectiveness of the proposed method.
基金This work was supported by the National Natural Science Foundation of China(Nos.11702059 and 11872145)the Guiding Plan of Natural Science Foundation of Liaoning Province(No.2019-ZD-0183).
文摘In this paper,the nonlinear dynamic behaviors of a hyperelastic cylindrical membrane composed of the incompressible Ogden material are examined,where the membrane is subjected to uniformly distributed radial periodic loads at the internal surface and surrounded by a thermal field.A second-order nonlinear differential equation describing the radially symmetric motion of the membrane is obtained.Then,the dynamic characteristics of the system are qualitatively analyzed in terms of different material parameter spaces and ambient tem-peratures.Particularly,for a given constant load,the bifurcation phenomenon of equilibrium points is examined.It is shown that there exists a critical load,and the phase orbits may be the asymmetrie homoclinic orbits of the“oo”type.Moreover,for the system with two centers and one saddle point,the dynamic behaviors of the system show softening phenomena at both centers,but the temperature has opposite effects on the stiffness of the structure.For a given periodically perturbed load superposed on the constant term,some complex dynamic behaviors such as quasiperiodic and chaotic oscillations are analyzed.With the Poincare section and the maximum Lyapunov characteristic exponent,it is found that the ambient temperature could lead to the irregularity and unpredictability of the nonlinear system,and also changes the threshold of chaos.
