Li, W, Ma, H & Gao, W 2019, 'A higher-order shear deformable mixed beam element model for accurate analysis of functionally graded sandwich beams', Composite Structures, vol. 221.View/Download from: Publisher's site
© 2019 Elsevier Ltd In this paper, a new higher-order shear deformation beam theory is developed by introducing the stress equilibrium condition. On the basis of the new shear deformation theory, novel shear deformable mixed beam elements with independent internal force fields and displacement fields are developed for accurate analysis of the functionally graded sandwich beams. Furthermore, a shear deformable beam element with additional interpolated axial displacement is also constructed in order to get reliable reference solutions. Two examples are presented to investigate the solution accuracy of different beam elements. Numerical results indicate that the present mixed beam elements can accurately predict the stress distributions over the cross section and ultimately give accurate displacement solutions. Moreover, the characteristics of axial displacement distributions and transverse shear strain distributions for functionally graded sandwich beams are discussed and the difficulty of getting accurate solutions by introducing a single form higher-order displacement function is pointed out. In these cases, the equilibrium-based beam theory and the corresponding mixed beam elements are more effective and reliable to obtain accurate solutions. Finally, the numerical stability for different beam elements is investigated and the results indicate the present higher-order shear deformable mixed beam element has excellent numerical stability.
Li, W & Ma, H 2019, 'A novel model order reduction scheme for fast and accurate material nonlinear analyses of large-scale engineering structures', Engineering Structures, vol. 193, pp. 238-257.View/Download from: Publisher's site
© 2019 Elsevier Ltd A new framework is developed for the fast and accurate analysis of large-scale engineering structures considering material nonlinearity. A fundamental linear model is constructed first by assigning nominal linear material parameters for each of the potentially nonlinear elements, and then, for each nonlinear element, a Nonlinear Deviation Force Vector (NDFV) is defined as the difference between the true nonlinear nodal force vector and the vector calculated using the nominal linear material parameters. In this way, the displacement of the nonlinear model can be expressed as a linear combination of a set of basis solutions of the fundamental linear model. These basis solutions include nodal displacement solutions due to the applied load and all unit components of NDFVs of nonlinear elements. Therefore, the values of these NDFVs, as combination coefficients in the displacement expression are the only unknowns for the whole structure and can be determined by considering a much smaller nonlinear equation system. It is noteworthy that no approximation is introduced in the proposed model order reduction scheme and the new scheme can be applied to the iterative solution process of both static and dynamic problems. Numerical examples are presented to show the effectiveness of the proposed scheme.
Cao, M, Ma, H & Wei, P 2018, 'A modified stiffness spreading method for layout optimization of truss structures', ACTA MECHANICA SINICA, vol. 34, no. 6, pp. 1072-1083.View/Download from: UTS OPUS or Publisher's site
Liu, L, Tan, P, Ma, H, Yan, W & Zhou, F 2018, 'A novel energy dissipation outrigger system with rotational inertia damper', ADVANCES IN STRUCTURAL ENGINEERING, vol. 21, no. 12, pp. 1865-1878.View/Download from: UTS OPUS or Publisher's site
Wei, C, Ke, C, Ma, H & Zhang, X 2018, 'A Modified Phase Field Model Based on Order Parameter Gradient and Simulation of Martensitic Transformation in Large Scale System', ACTA METALLURGICA SINICA, vol. 54, no. 8, pp. 1204-1214.View/Download from: UTS OPUS or Publisher's site
Hu, Z, Wang, Z, Su, C & Ma, H 2018, 'Reliability Based Structural Topology Optimization Considering Non-stationary Stochastic Excitations', KSCE JOURNAL OF CIVIL ENGINEERING, vol. 22, no. 3, pp. 993-1001.View/Download from: UTS OPUS or Publisher's site
Jia, SM, Wang, ZQ, Zhao, L & Ma, HT 2018, 'A simulation method based on explicit time-domain iteration scheme for nonlinear random vibration analysis of isolated bridges under multi-support excitation', Gongcheng Lixue/Engineering Mechanics, vol. 35, no. 12, pp. 116-123.View/Download from: UTS OPUS or Publisher's site
© 2018, Engineering Mechanics Press. All right reserved. Due to the randomness and the spatial variability of ground motion, the nonlinear behavior of isolation bearings and the limited number of isolation bearings installed in each bridge, the seismic response analysis of an isolated bridges is a typical multi-input locally nonlinear random vibration problem. The Bouc-Wen model is used to describe the nonlinear restoring force of isolation bearings, and then the nonlinear equation of motion of isolated bridges under multi-support seismic excitation is established. The nonlinear equation of motion is rewritten as a quasi-linear equation expressed in terms of state variables. Based on the precise time-integration method and the Range-Kutta method, an explicit time-domain dimension-reduced iteration scheme is established. Using this efficient scheme, the statistical characteristics of the random seismic responses of isolated bridges under multi-support seismic excitation are calculated by stochastic simulation. Numerical examples show the efficiency of the proposed approach and its application in the nonlinear random vibration analysis of isolated bridges under multi-support seismic excitation.
Li, W, Ma, H & Gao, W 2017, 'Geometrically exact curved beam element using internal force field defined in deformed configuration', INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS, vol. 89, pp. 116-126.View/Download from: Publisher's site
Gao, X, Li, L & Ma, H 2017, 'An Adaptive Continuation Method for Topology Optimization of Continuum Structures Considering Buckling Constraints', INTERNATIONAL JOURNAL OF APPLIED MECHANICS, vol. 9, no. 7.View/Download from: Publisher's site
Chen, H, Tan, P, Ma, H & Zhou, F 2017, 'Response spectrum analysis considering non-classical damping in the base-isolated benchmark building', STRUCTURAL ENGINEERING AND MECHANICS, vol. 64, no. 4, pp. 473-485.View/Download from: Publisher's site
Li, Y, Wei, P & Ma, H 2017, 'Integrated optimization of heat-transfer systems consisting of discrete thermal conductors and solid material', INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, vol. 113, pp. 1059-1069.View/Download from: Publisher's site
Hu, Z, Su, C, Chen, T & Ma, H 2016, 'An explicit time-domain approach for sensitivity analysis of non-stationary random vibration problems', JOURNAL OF SOUND AND VIBRATION, vol. 382, pp. 122-139.View/Download from: Publisher's site
Su, C, Huang, H & Ma, H 2016, 'Fast Equivalent Linearization Method for Nonlinear Structures under Nonstationary Random Excitations', JOURNAL OF ENGINEERING MECHANICS, vol. 142, no. 8.View/Download from: Publisher's site
Chen, TC, Li, YY, Su, C & Ma, HT 2016, 'A study on identification-probability histogram method for modal identification of structures subjected to ambient excitations', Zhendong Gongcheng Xuebao/Journal of Vibration Engineering, vol. 29, no. 4, pp. 561-567.View/Download from: Publisher's site
© 2016, Nanjing Univ. of Aeronautics an Astronautics. All right reserved. During the modal identification of a structure subjected to ambient excitations, the system order as a crucial computation parameter is not easy to be determined, and the stabilization diagram method based on assumed system orders is often adopted to help the identification. But how to distinguish the stabilization axes is in fact subjective, which may lead to possible inclusion of pseudo vibration modes instead of real modes into the final results. To avoid these problems, an identification-probability histogram (IpHist) method in use of the data mining technique is proposed in the present paper. Firstly, the stochastic subspace method is applied to identify the alternative modes with different assumed system orders. Then, all the alternative modes are clustered into several categories by using the criteria of frequency tolerance and MAC tolerance, and the identification probability of each category is obtained along with the corresponding identification-probability histogram. Finally, the clustered modes with large identification probability are chosen to be the structural modes. By taking a four-story Benchmark model provided by the IASC-ASCE structural health monitoring workgroup as example, numerical results are presented to illustrate the effectiveness and anti-noise capacity of the proposed IpHist method for modal identification of structures subjected to ambient excitations.
Hu, ZQ & Ma, HT 2015, 'On the consistency issue of adjoint methods for sensitivity analysis of dynamic responses', Zhendong yu Chongji/Journal of Vibration and Shock, vol. 34, no. 20, pp. 167-173.View/Download from: Publisher's site
©, 2015, Chinese Vibration Engineering Society. All right reserved. The inconsistency issue of adjoint variable methods (AVMs) for sensitivity analysis of transient dynamic responses was investigated. The differentiate-then-discretize and discretize-then-differentiate approaches were considered, focusing on their computational accuracy, convergence rates and result consistency. Based on the basic idea of the explicit time-domain method for dynamic analysis, a concise discretize-then-differentiate AVM formulation was presented. It is found that the inconsistency of the differentiate-then-discretize approach is caused by the fact that numerical solutions for dynamic responses satisfy equations of motion only at integration points in the time domain. However, despite this consistency problem, this approach is still reliable for sensitivity analysis of dynamic responses.
Chen, TC, Su, C, Hu, ZQ & Ma, HT 2015, 'An explicit time-domain method in sensitivity analysis of non-stationary random responses', Zhendong Gongcheng Xuebao/Journal of Vibration Engineering, vol. 28, no. 4, pp. 503-509.View/Download from: Publisher's site
©, 2015, Nanjing University of Aeronautics an Astronautics. All right reserved. Aiming at the structural vibration problem under non-stationary excitation, time-domain method of high efficiency is explored in the present study to determine the sensitivity of covariance of random response. Firstly, a time-domain formulation is derived for computing the sensitivity of deterministic response. Then, according to a general expression of the sensitivity of covariance, an explicit time-domain formulation is deducted to calculate the sensitivity of covariance of non-stationary random response. This formulation is also suitable for the case of stationary excitation if sensitivity of covariance of the transient response is concerned. By taking a frame and a truss subjected to different types of non-stationary excitations as examples, comparisons of the numerical results obtained with different methods illustrate the effectiveness of the proposed method.
Su, C, Huang, H, Ma, H & Xu, R 2014, 'Efficient MCS for random vibration of hysteretic systems by an explicit iteration approach', EARTHQUAKES AND STRUCTURES, vol. 7, no. 2, pp. 119-139.View/Download from: Publisher's site
Wei, P, Ma, H & Wang, MY 2014, 'The stiffness spreading method for layout optimization of truss structures', STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION, vol. 49, no. 4, pp. 667-682.View/Download from: Publisher's site
Chen, T, Ma, H & Gao, W 2013, 'A new approach to stability analysis of frame structures using Trefftz-type elements', JOURNAL OF CONSTRUCTIONAL STEEL RESEARCH, vol. 82, pp. 153-163.View/Download from: Publisher's site
Chen, T, Ma, H & Gao, W 2012, 'Comprehensive Investigation into the Accuracy and Applicability of Monte Carlo Simulations in Stochastic Structural Analysis', CMES-COMPUTER MODELING IN ENGINEERING & SCIENCES, vol. 87, no. 3, pp. 239-269.
Su, C, Zhao, S & Ma, H 2012, 'Reliability analysis of plane elasticity problems by stochastic spline fictitious boundary element method', ENGINEERING ANALYSIS WITH BOUNDARY ELEMENTS, vol. 36, no. 2, pp. 118-124.View/Download from: Publisher's site
Luo, Z, Zhang, N, Gao, W & Ma, H 2012, 'Structural shape and topology optimization using a meshless Galerkin level set method', International Journal For Numerical Methods In Engineering, vol. 90, no. 3, pp. 369-389.View/Download from: UTS OPUS or Publisher's site
This paper aims to propose a meshless Galerkin level set method for shape and topology optimization of continuum structures. To take advantage of the implicit free boundary representation scheme, the design boundary is represented as the zero level set of a scalar level set function, to flexibly handle complex shape fidelity and topology changes by maintaining concise and smooth interface. Compactly supported radial basis functions (CSRBFs) are used to parameterize the level set function and construct the shape functions for meshfree approximations based on a set of unstructured field nodes. The meshless Galerkin method with global weak form is used to implement the discretization of the state equations. This provides a pathway to unify the two different numerical stages in most conventional level set methods: (1) the propagation of discrete level set function on a set of Eulerian grid and (2) the approximation of discrete equations on a set of Lagrangian mesh. The original more difficult shape and topology optimization based on the level set equation is transformed into a relatively easier size optimization, to which many efficient optimization algorithms can be applied. The proposed level set method can describe the moving boundaries without remeshing for discontinuities. The motion of the free boundary is just a question of advancing the discrete level set function in time by solving the size optimization. Several benchmark examples are used to demonstrate the effectiveness of the proposed method. The numerical results show that the proposed method can simplify numerical process and avoid numerical difficulties involved in most conventional level set methods. It is straightforward to apply the proposed method to more advanced shape and topology optimization problems. Copyright Â© 2011 John Wiley & Sons, Ltd.
Wang, R, Gan, Q, Huang, Y & Ma, H 2011, 'Estimation of Tension in Cables with Intermediate Elastic Supports Using Finite-Element Method', JOURNAL OF BRIDGE ENGINEERING, vol. 16, no. 5, pp. 675-678.View/Download from: Publisher's site
Ma, H 2010, 'Exact solution of vibration problems of frame structures', INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, vol. 26, no. 5, pp. 587-596.View/Download from: Publisher's site
Ma, H, Su, C & Huang, Z 2009, 'A new approach to aerostatic analysis of long-span bridges', PROCEEDINGS OF THE INSTITUTION OF CIVIL ENGINEERS-STRUCTURES AND BUILDINGS, vol. 162, no. 2, pp. 129-135.View/Download from: Publisher's site
Luo, Z, Tong, L & Ma, H 2009, 'Shape and topology optimization for electrothermomechanical microactuators using level set methods', Journal of Computational Physics, vol. 228, no. 9, pp. 3173-3181.View/Download from: UTS OPUS or Publisher's site
In this short note, a shape and topology optimization method is presented for multiphysics actuators including geometrically nonlinear modeling based on an implicit free boundary parameterization method. A level set model is established to describe struc
Ma, H & Su, C 2006, 'A new approach to advanced structural analysis and optimization', CJK-OSM 4: The Fourth China-Japan-Korea Joint Symposium on Optimization of Structural and Mechanical Systems, 4th China-Japan-Korea Joint Symposium on Optimization of Structural and Mechanical Systems, DALIAN UNIV TECHNOL PRESS, Kunming, PEOPLES R CHINA, pp. 653-658.