Yueming Li

Bio: Yueming Li is an academic researcher from Xi'an Jiaotong University. The author has contributed to research in topics: Computer science & Vibration. The author has an hindex of 19, co-authored 93 publications receiving 1112 citations.

Solutions of dynamic and acoustic responses of a clamped rectangular plate in thermal environments

Abstract: This work presents an investigation of vibration and acoustic response characters of a clamped rectangular thin plate in thermal environments. The general form of governing equation of plate flexural vibration with considering thermal loads is established, and the influence of uniform temperature change on response characters is studied in detail. A set of double sinusoidal mode shape functions for fully clamped boundaries is used to describe the displacement distribution. The governing equation is solved with Fourier series expansion to discuss the natural vibration and dynamic responses of a clamped plate in thermal environments. Accordingly, acoustic radiation characteristics are obtained based on Rayleigh integral. Results show that natural frequencies decrease with the increment of plate temperature, and the first natural frequency is much more sensitive to thermal environment changes. Response curves of plate vibration and radiated sound power shift toward lower frequency range, and the response amp...

Adaptive Reduced-Order-Model-Based Control-Law Design for Active Flutter Suppression

Abstract: The design of classic active flutter controllers has often been based on low-fidelity and low-accuracy linear aerodynamic models. Most of these models were usually treated as a linear time-invariant system, without considering time-varying parameters, such as the Mach number, the angle of attack, the Reynolds numbers, etc. A high-fidelity reduced-order model based on the proper orthogonal decomposition adaptation algorithm is used to develop a new general linear parameter-varying aeroservoelastic model with aerodynamic nonlinearity. A robust gain-scheduling control-law design method for active flutter suppression based on the proposed linear parametervarying model is investigated. The proposed design method is demonstrated with the Goland wing aeroelastic model. The simulation results show that the linear parameter-varying gain-scheduled controller can effectively suppress flutter over a range of airspeeds, and the flutter boundary in the transonic regime is simultaneously increased by nearly 20% to 30%.

Topology optimization to minimize the dynamic compliance of a bi-material plate in a thermal environment

Abstract: Topology optimization to minimize the structural dynamic compliance in a thermal environment is carried out in this paper. A bi-material plate subjected to a uniform temperature rise is investigated. The structure is driven by a time-harmonic surface loading with prescribed excitation frequency and amplitude. The stress induced by the equivalent thermal force which is known as design-dependent load could reduce the stiffness of the structure, thus altering the optimal topology design. A way to carry out the optimization in the thermal environments is presented here. The thermal stress is first evaluated, and then considered as pre-stress in the subsequent dynamic analysis with the introduction of the geometric stiffness matrix. The sensitivity analysis is carried out through adjoint method which can save significant computational resources by avoiding the derivatives of the thermal displacement (or thermal stress) on the design variables. The cost to obtain these derivatives can be very high since each design variable affects all the nodal displacements. The structural damping is neglected. Several pre-buckling cases are investigated.

Mechanics of composite materials

Abstract: INTRODUCTION TO COMPOSITE MATERIALS Chapter Objectives Introduction Classi?cation Recycling Fiber-Reinforced Composites Mechanics Terminology Summary Key Terms Exercise Set References MACROMECHANICAL ANALYSIS OF A LAMINA Chapter Objectives Introduction Review of De?nitions Hooke's Law for Different Types of Materials Hooke's Law for a Two-Dimensional Unidirectional Lamina Hooke's Law for a Two-Dimensional Angle Lamina Engineering Constants of an Angle Lamina Invariant Form of Stiffness and Compliance Matrices for an Angle Lamina Strength Failure Theories of an Angle Lamina Hygrothermal Stresses and Strains in a Lamina Summary Key Terms Exercise Set References APPENDIX A: MATRIX ALGEBRA Key Terms APPENDIX B: TRANSFORMATION OF STRESSES AND STRAINS Transformation of Stress Transformation of Strains Key Terms MICROMECHANICAL ANALYSIS OF A LAMINA Chapter Objectives Introduction Volume and Mass Fractions, Density, and Void Content Evaluation of the Four Elastic Moduli Ultimate Strengths of a Unidirectional Lamina Coefficients of Thermal Expansion Coefficients of Moisture Expansion Summary Key Terms Exercise Set References MACROMECHANICAL ANALYSIS OF LAMINATES Chapter Objectives Introduction Laminate Code Stress-Strain Relations for a Laminate In-Plane and Flexural Modulus of a Laminate Hygrothermal Effects in a Laminate Summary Key Terms Exercise Set References FAILURE, ANALYSIS, AND DESIGN OF LAMINATES Chapter Objectives Introduction Special Cases of Laminates Failure Criterion for a Laminate Design of a Laminated Composite Other Mechanical Design Issues Summary Key Terms Exercise Set References BENDING OF BEAMS Chapter Objectives Introduction Symmetric Beams Nonsymmetric Beams Summary Key Terms Exercise Set References INDEX