材料力學(xué)總結(jié)

1、材料力學(xué)總結(jié)材料力學(xué)名詞解釋及填空名詞解釋1、Stress（應(yīng)力）the force per unit area , or intensity of the force distributed over a given section, is called stress. =F/A2、normal stress（正應(yīng)力 ）The internal force is therefore normal to the plane of the section and the corresponding stress is described as the normal stress.3、Sheari

2、ng stress（剪應(yīng)力 ）The internal force is the shear on the plane of the section and the corresponding stress is described as the shearing stress.4、Linear Strain（ 應(yīng)變 ）The normal strain in a member can be defined as the deformation of the meter of the per unit length.5、The main objective of the study the m

3、echanics of materials材料力學(xué)的任務(wù)）is to provide the future engineer with the means of analyzing and designing various machines and loading-bearing structures.6、Saintvenaiit，s principle （圣維南原理）For two sets of statically equivalent forces, except in the immediate vicinity of the points of application of th

4、e loads, the stress distribution may be assumed independent of the actual mode of application of the loads （this statement is not only to axial load, but to practically any type of load） 7、Work-enerv principle（功能原理）The Work-energy Principle: In the process of the deformation of a elastomer, the stra

5、in energy which is stored in elastomer is equal to the work of the external force in number. This is the Work-energy Principle and it can be represented as V e =W.8、effective length （有效長(zhǎng)度） is defined as real length multiplied by factor of length9、principle plane（ 主平面 ）is the plane in which the shear

6、ing stress equals zero, and normal stresses achieve maximum or minimum.Principle stress（ 主應(yīng)力 ）The normal stress which is exerted on the principle plane is called the principle stress.10、Radius of radius of gyration 【 revolution 】（慣 性半徑） of an area can be calculated by the following formula i=I/AWher

7、e i =the moment of inertia of an areaA=the area of an cross section11、isotropic materials （各向同性材料） are the materials whose elastic constants are independent of direction.12、homogeneous materials （均勻性材料） are the materials whose elastic properties are the same everywhere.13、The strain energy density（

8、應(yīng)變能密度 ）The strain energy in the unit volume can be defined as the strain energy density.14、Hooke 's law （胡克定律） may be expressed more fully by saying that1】when the stress increases,the measured strain increases in the same ratio2】 when the stress diminishes, the measured strain diminishes in the

9、 same ratio3】when the stress is removed, no strain can be measuredFor a small deformation,the stress is directly proportional to the strain.15、Hooke 's law for shearing stress（ 剪切胡克 定律）The relation =G is known as Hooke 's law for shearing stress. Strain and constant Gis called the modulus of

10、 rigidity or shear modulus of material.16、Generalized Hooke 's law（廣義胡可定律）17、Poisson ratio （ 泊松比 ）is defined as the ratio of lateral contraction （strain） to longitudinal extension （strain） of a bar under terminal tension.18、factor of safety （安全因數(shù)） ultimate load over allowable load19、stress-conce

11、ntration factor k （應(yīng)力集中因數(shù) K ） =maximum stress over average stress20、statically indeterminate problem （靜不定問(wèn) 題） is the problem in which the reactions and internal forces can not be determined by static only , analysis of deformation is needed.21、neutral surface （中性層） is defined as the surface between

12、the top and bottom of a beam in which longitudinal line do not change.22、Neutral axis （中性軸） The neutral surface intersects a transverse section along a straight line called the neutral axis of the section. The intersection of the neutral surface with a transverse section is called the neutral axis o

13、f the section.23、principle of superposition （疊加原理） for all linear systems （a beam can be modeled as a linear system ）,24、the quantity the term =l /i （柔度 ） is known as the slenderness ratio of the column. Where l= effective lengthi= the radius of gyration25、The theory of strength（ 強(qiáng)度理論 ）The assumptio

14、n concerning the damage or the losing effect of the material is called the theory of strength.26、buckling （ 失穩(wěn) ）A stage when the column suddenly becomes sharply curved instead of remaining straight as the load is applied is called buckling.27、The critical force （ 臨界壓力 ）The value of the compressive f

15、orce which is right on the boundary between the stable balance and the unstable balance is called the critical force.28、The critical stress （ 臨界應(yīng)力 ）The corresponding stress of the critical force is described as the critical force.29、Euler 's Formula （ 歐拉公式 ）Euler 's Formula can be expressed

16、asFcr= 2EI le2 in which: Fcr denotes the critical loadE denotes the modulusI denotes the minimum moment of inertia of areale denotes the equivalent length30、Assumption for a bar （ 拉壓的平面假設(shè) ） The hypothesis assumes that the section keeps being a plane after deformation.31、Assumption for torsion （ 扭轉(zhuǎn)平面

17、假設(shè) ） When a circular shaft is subjected to a torsion, every cross section remains plane and undamaged.32、Assumption for bending （ 彎曲平面假設(shè) ） Under bending, the cross section of the beam remains plane and has a constant curvature. And the new cross section still perpendicular to axis.32、極慣性矩The polar m

18、oment of inertia of an area is defined as the polar moment of inertia of an area with respect to a point as the integralIp=2dA33、慣性矩The moment of inertia of an area is defined as the second moment of the area with respect to an axis as the integral I= y2dA.34、靜矩The static moment of an area is define

19、d as the first moment of an area with respect to an axis as the integral Sz= ydA.填空題1 三個(gè)材料假設(shè)Homogeneousity assumption 、 Continuity assumption 、 Isotropy assumptionPhysical relation 、2 三個(gè)關(guān)系 Geometric relation Equilibrium relation3 限制梁撓度的三個(gè)條件Boundary condition 、 Constraint condition 、 Continuity condition4 三種約束方式1) 固定端 fixed end2) 固定