How to calculate the force of emergency

1. △R/R=K* ε， Use this formula to calculate the strain, and then the stress = E* ε
e is the elastic molus of the measured object. If you are interested in the knowledge of strain gauge, you are welcome to chat with me,

2. Generally, bolts are added at the connecting hole position, the force is measured with a tension meter, and then multiplied by half of the diameter of the bolt hole distribution is the starting friction torque.

3. Strain can't be changed into stress,
and then defined in * initial condition, type = stress. Check the manual for details

4.

Strain = stress / elastic molus

according to the axis diagram, the force on the response axis is obtained. The axial force divided by the sectional area of the shaft is the stress. The magnitude of stress is the basis to judge whether the material is plastic deformation or not. At present, most of them rely on software for computer analysis

When the material is uniformly elongated or shortened, the ratio of the change to the original length is the strain. Sometimes strain can be used to judge failure. When the material is uniformly stretched or shortened, the ratio of the change to the original length is the strain. Sometimes strain can be used to judge failure

extended data:

precautions for stress and strain:

when using, it is not advisable to use excessive tension or pressure to give impact force, so as to avoid damage to the displacement meter or connecting spring huangpian

in order to rece the error, it is not suitable to change the experimenter or change the test direction ring the test

in the test, do not touch the metal bracket of the instrument with hands, and hold the handle to rece the error caused by the influence of human body temperature

When

reading, repeat n times to avoid error

5. There are 21 basic equations in elasticity, such as strain displacement equation, stress-strain relation (Hooke's law), equilibrium equation, force and displacement boundary conditions, etc
no matter what finite element software, the displacement function u, V, W is solved by displacement method, and then the strain function
is used ε- According to the relationship of UVW,
9 strain tensors can be solved, and then
9 stress tensors can be calculated by hook's law.

6. If the strain gauge is used to measure the force, it is necessary to ensure that the object under positive force is within the range of elastic deformation when it is under the force. The amount of deformation measured by the strain gauge is related to the area of the force. Knowing these amounts, the force can be calculated.

7. The first step: lengthen the length of the amorphous model along a certain axis (such as axis a) (set the length of axis A to 105% * a)< The second step is MD balance< The third step is to calculate the energy after equilibrium; The energy at 5% strain is obtained< The fourth step is to lengthen the a-axis by 10% and repeat the second and third steps to obtain the energy at 10% strain
Step 5: repeat the above steps to get the stress-strain curves of different strains.

8. A L It is the original parameter of the sample
A, and l is the immediate parameter ring the experiment
conditional stress σ= F/A
conditional strain ε=Δ L/L
true stress σ= F / a
true strain D ε= DL / L
by volume invariance, Al = a. L
so σ= F/A=F/A L/ L
= σ 1+ ε< br /> ε= SdL/L)L-L)= In1+ ε
it seems that there is also a real section shrinkage

9.

The formula of elastic molus (E), shear molus (g) and Poisson's ratio (V) is as follows:

G = E / [2 (1 + V)]

Poisson's ratio: when the material elongates (or shortens) along the load direction, it will shorten (or elongate) perpendicular to the load direction. Strain in vertical direction ε L and strain in load direction ε The negative value of the ratio is called Poisson's ratio. If V is Poisson's ratio, then v=- ε l/ ε In the stage of elastic deformation, V is a constant

shear molus: refers to the ratio of shear stress to corresponding shear strain in the elastic deformation stage

elastic molus: in the stage of elastic deformation, the stress and strain of a material change into a positive proportional relationship (that is, in accordance with Hooke's law), and its proportional coefficient is called elastic molus. The unit of molus of elasticity is dyne per square centimeter“ "Elastic molus" is a physical quantity to describe the elasticity of material, which is a general term, including "Young's molus", "shear molus", "bulk molus" and so on

extended data:

when an object deforms under force, the degree of deformation at each point in the body is generally not the same. The mechanical quantity used to describe the degree of deformation at a point is the strain at that point. For this reason, an element can be found at this point to compare the size and shape of the element before and after deformation

when the element body is a regular hexahedron in Cartesian coordinates, the rectangular change of two mutually perpendicular edges of the element body after deformation is defined as angular strain or shear strain γ Expression

The shear strain of

point in X-Y direction, Y-Z direction and z-x direction can be divided into γ xy、 γ yz、 γ zx The decrease of shear strain at right angle is positive, and vice versa