Research On Mechanical Behavior Functionally Graded Beam

Functionally graded materials(FGM) constitute a material refers to the elements (composition, structure) along a certain direction to the other side by the side of positive change for the gradient,so that the nature and function of materials was also a new type of gradient changes in non-uniform composite material.FGM with its position in the space of continuous changes in the volume content of components, which makes the nature of the structure of the location in space are also continuous changes,thereby eliminating the material properties of the mutation, you can better avoid or reduce the phenomenon of stress concentration.FGM can give full play to high temperature ceramics, and metal corrosion-resistant high strength, good toughness characteristics,but also a very good solution to match the force of metal and ceramic bond strength caused by low heat expansion coefficient of non-conforming issues.Functionally graded thermal barrier materials in high temperature environment show good performance, are considered for future high-speed spacecraft, the nuclear industry and chemical industry in areas such as a potential material.Therefore,the functionally graded structure of the mechanical behavior of materials research,has attracted the interest of many researchers.In this paper, research the bending of FGM beams,buckling and post-buckling of FGM beam and so on.(一) Functionally graded material beam bending problem.First of all, based on the third-order shear beam theory of FGM beam equation of motion. These equations of motion for the bending problem can be degraded static control equations of bending and stability analysis, and the third-order shear beam theory and the equation can degenerate into the first-order shear and the classical theory of the basic equation.The bending governing equations(only under the mechanical load), the simply supported and clamped boundary conditions that are dimensionless are discreted.In the simply supported and clamped boundary conditions,center deflection of FGM beams are derived using DQM.Finally, get the numerical solutions of the three theories FGM beams under large deflection and small deflection bending problem.The use of numerical results from the study of the material gradient nature of factors such as slenderness ratio on the impact of beam bending, and compared the corresponding results under three theories.(二)Functionally graded beams stability analysis.The buckling and post buckling governing equations(only under thermal load and material properties and temperature independent) and clamped boundary conditions that are dimensionless are discreted.Critical buckling loads of FGM beams are derived using DQ method,and equation numbers is unknown quantities.Finally, the critical thermal buckling loads have been got for the clamped functionally graded beams,and has been the critical thermal buckling load curve with the gradient parameters.The results obtained indicated that critical buckling load increases with increase in gradient parameters for agiven value of slenderness ratio.Critical buckling loads of the third-order theory increase as slenderness ratio increases because the transverse shear deformation decreases.