材料成形力学1.ppt

材料成形力学（双语教学） The Contents of the Subject 1 Introduction (引言) 2 Stress Analysis （应力分析） 3 Strain Analysis （应变分析） 4 Yield Criteria for Ductile Metals （塑性材料的屈服准则） 5 Stress-Strain Relation （应力－应变关系） 6 Stress Evaluation Approch- Slab Method （工程法） 7 Plain Strain Slip-line Field Theory（平面应变滑移线场理论） 8 Extremum Principle for a Rigid Perfectly Plastic Material （刚塑性材料的极限分析原理） Chapter 1 Introduction Chapter 1 Introduction * Mechanics of Material Forming 1) Elastic and plastic deformation (弹性变形和塑性变形) A) Elastic deformation Force (small) (力) Stress State (应力状态) Deformation (strain) (变形或应变) Stress-Strain: linear(线性的) Deformation: recoverable （变形） reversible Elastic deformation Theory of elasticity (elastic deformed body) (弹性理论) （弹性变形体） 1.1 Definition and scope of the subject B) Plastic deformation Stress-Strain: non-linear(非线性的) Deformation: irrecoverable(不可恢复的) （变形） irreversible Plastic deformation Theory of Plasticity (塑性理论) 2) Theory of Plasticity (塑性理论) It is concerned with the mathematical study of stress and strain in a plastically deformed body. 塑性理论主要考虑塑性变形体内应力－应变的数学关系。 Object （研究对象） Research method （研究方法） Ductile metal materials(塑性金属材料)，independent of time. Experimental observation Macroscopic behaviour. Formulization It is different from material science. Physical explanation Microscope structure Combine Theory of plasticity Material science Unified theory of plasticity Our task 3) Nature of Engineering Plasticity (工程塑性理论的特性) Practice and application （实践和应用） To construct relation between stress and strain for metals and their alloys To develop mathematical technique, determine stress distribution and predict plastic deformation Two aims Features Complex stress state Non-linear Math. difficulties Assumptions approximations 1864. Tresca Yield criterion 1.2 Brief historical account H.E.Tresca carried out experime