文档介绍：CHAPTER 7
ANALYSIS OF
STRESS AND STRAIN
Mechanics of Materials
第七章应力状态与应变状态分析
材料力学
CHAPTER 7 ANALYSIS OF THE STATE OF STRESS AND STRAIN
§7–4 PRINCEPAL STRESSES AND THEIR TRAJECTORIES OF THE BEAM
§7–5 ANALYSIS OF TRIAXIAL STRESSED STATE—METHOD OF STRESS CIRCLE
§7–6 ANALYSIS OF STRAIN IN A PLANE
§7–7 RELATION BETWEEN STRESS AND STRAIN UNDER
COMPLEX STRESSED STATE—(GENERALIZED HOOKE’S LAW)
§7–8 STRAIN -ENERGY DENSITY PLEX STRESSED STATE
§7–1 CONCEPTS OF THE STATE OF STRESS
§7–2 ANALYSIS OF THE STATE OF PLANE STRESS — ANALYTICAL METHOD
§7–3 ANALYSIS OF THE STATE OF PLANE STRESS — GRAPHYCAL METHOD
第七章应力状态与应变状态分析
§7–1 应力状态的概念
§7–2 平面应力状态分析——解析法
§7–3 平面应力状态分析——图解法
§7–4 梁的主应力及其主应力迹线
§7–5 三向应力状态研究——应力圆法
§7–6 平面内的应变分析
§7–7 复杂应力状态下的应力-- 应变关系 ——(广义虎克定律)
§7–8 复杂应力状态下的变形比能
§7–1 CONCEPTS OF THE STAFE OF STRISS
1、Forward
1)、Investigation on the tensile, compressive and torsional test of cast iron
and low-carbon steel
M
Low-carbon steel
Cast iron
P
P
Cast iron in tension
P
Cast iron pression
2)、How will the member rupture bined deformations?
M
P
ANALYSIS OF STRESS AND STRAIN
§7–1 应力状态的概念
应力状态与应变状态
一、引言
1、铸铁与低碳钢的拉、压、扭试验现象是怎样产生的?
M
低碳钢
铸铁
P
P
铸铁拉伸
P
铸铁压缩
2、组合变形杆将怎样破坏?
M
P
4、Expression of stresses in general case
3、Element:Element— Delegate of a point in the member. It is a infinitesimal geometric body enveloping the studied point. mon use it is a correctitude cubic body.
Properties of an element—a、Stresses are distributed
uniformly in the sections;
b、The stresses in two planes that are parallel to each other are equal.
2、State of stress at a point:
There are countless sections through a point. The gathering of stresses in all sections is called the state of stress at this point.
x
y
z
s
x
sz
s
y
txy
ANALYSIS OF STRESS AND STRAIN
四、普遍状态下的应力表示
三、单元体:单元体——构件内的点的代表物,是包围被研究点
的无限小的几何体,常用的是正六面体。
单元体的性质——a、平行面上,应力均布;
b、平行面上,应力相等。
二、一点的应力状态:
过一点有无数的截面,这一点的各个截面上应力情况的集合,称为这点的应力状态(State of Stress at a Given Point)