General Consideration Definition The separation of the placenta from its site of implantation after 20 weeks of gestation or during the course of delivery Frequency 0.51%0-2.33%(our country) 1%o(other countries) Incidence of fetal death

General Consideration Antenatal cardiovascular changes Blood volume increase by 40%-60%0 Peaking at 32-34 weeks the expansion in plasma volume is greater than that expansion of red cell mass Cardiac output Increase by 40%6-50% Peaking at 20-24 weeks

Definition Abruptio Placentae( placental abruption): premature separation of the normally implanted placenta from the uterine wall

Review: Inverse method逆解法 Select satisfying the compatibility equation 设定中,并满足相容方程V4φ=0(2.12.11) find the stress components by由下式求出应力分量 Txy--02d/ (2.12.10) find the surface force components by 由下式对给定坐标的物体求出面力分量

Section 12.1 Introduction and Assumptions 引言和假定 a plate is a body bounded by two closely spaced parallel planes and one or more prismatical surfaces normal to the planes

2.1 Plane stress and plane strain 平面应力问题与平面应变问题 2.2 Differential equations of equilibrium 平衡微分方程 2.3 Stress at a point. Principal stresses 一点的应力，主应力 2.4 Geometrical equations. Rigid-body displacements 一几何方程，刚体位移 Shear stress trajectories in a cantilever beam 悬臂梁的剪应力轨迹线 2.6 Physical equations. 物理方程 2.7 Boundary conditions 边界条件 2.8 Saint-venant`s principle-1 圣维南原理 2.9 solution of plane problem in terms of displacements 按位移求解平面问题 2.10 solution of plane problem in terms of stresses 按应力求解 2.11 Case of constant body forces 常体力情况 2.12 Airy`s stress function. Inverse method and semi-inverse method 艾瑞应力函数，逆解法，半 逆解法

Introduction-1导引-1 The finite element method is an extension of the analysis techniques(matrix method) of ordinary framed structures. 有限元法是刚架结构分析技术的扩充。 The finite element method was pioneered in the aircraft industry where there was an urgent need for accurate analysis of complex airframe 有限元法首先应用于飞机工业

I. Choose the Correct Answer 1. Which of the following quantities are independent of the choice of inertial frame? (There may be more than one correct answer) (A)Velocity (B)Acceleration (C)Force (D)Work Solution: In all the inertial frame, the forces acted on a body are same,=ma=F'=ma', therefore the force and acceleration are independent of the choice of inertial frame

I. Choose the Correct Answer 1. The magnitude of the force of gravity between two identical objects is given by Fo. If the mass of each object is doubled but the distance between them is halved, then the new force of between the objects will be

10-1刚体绕平行轴转动的合成