How to calculate the stiffness of the force displacement curve

1.

Stiffness unit n / m should refer to the stiffness of the spring, that is, the elastic coefficient of the spring, f = KX, f is the working tension (compression) force of the spring, x, the length of tension (compression) elongation (or compression); K. Spring stiffness

and EI refers to the bending stiffness of the member, and the unit is the unit after multiplying the units of E and I. as you said, the unit of E is n / mm2, and the unit of I (such as b * H ^ 3 / 12) is MM4 --- the bending stiffness unit is n.mm2, no problem, The length unit is m, and the bending stiffness is n.m2

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extended data:

stiffness refers to the ability of a material or structure to resist elastic deformation under force. It is the characterization of the difficulty of elastic deformation of material or structure. The stiffness of a material is usually measured by the molus of elasticity E. In the macro elastic range, stiffness is the proportional coefficient of the load and displacement of the part, that is, the force required to cause the unit displacement. Its reciprocal is called flexibility, which is the displacement caused by unit force. Stiffness can be divided into static stiffness and dynamic stiffness

Generally speaking, the stiffness and elastic molus are different. The elastic molus is the property of material components; Stiffness is the property of structure. In other words, the elastic molus is the microscopic property of the material, while the stiffness is the macroscopic property of the material

in mechanics of materials, the proct of elastic molus and geometric properties of corresponding section is expressed as various kinds of stiffness, such as GI for torsional stiffness, EI for bending stiffness, EA for tension compression stiffness

The

stiffness coefficient is a basic physical quantity used to describe the elastic deformation of materials under external force. More generally speaking, it is the end force required to proce unit displacement at the end of the rod. The expression is EA / L, where e is the elastic molus of the member, a is the sectional area of the member, and l is the length of the member

There are two methods to determine the stiffness coefficient of rolling mill

The non-linear part of the elastic curve often changes because of the uneven gap and contact between the parts of the rolling mill. In order to eliminate the influence of the non-linear section, the manual zero position method is often used in the actual proction. That is, before rolling, the roll is preloaded to a certain pressure P0 (or press down the motor current as the standard), and then the reading of the roll gap indicator is set to zero, which is called manual zero position

The

bounce equation is of great significance for mill adjustment. It can be used to set the original roll gap. The bounce equation represents the relationship between the rolled out thickness and the roll gap and rolling force. It can be used as the basic formula for indirectly measuring the thickness of rolled piece

2. This answer is not misleading. You say that it is the molus of elasticity, which is the ratio of the applied force to the deformation. The stiffness is the proct of elastic molus and moment of inertia, and the bending stiffness is EI.

3. You have a good understanding“ Stiffness is the ability of a structure to resist deformation when it is stressed, or the ability to maintain its original shape. It mainly refers to a kind of problem in mechanics of materials, not the stiffness of a specific structure. For elastic structures, stiffness coefficient (defined as displacement in force / force direction) is adopted, such as spring stiffness. The stiffness coefficient is a comprehensive index of the shape and material of the elastic structure (there can be different elastic materials). It has many (unlike the spring, there is only one). For example, if you tilt the direction of the force in the figure, the stiffness coefficient is not the same. Add a couple to the area of the force action point in your figure, measure the corresponding torsion angle, and get the torsion stiffness coefficient of the couple on the steering.

4. The methods are as follows: using extensometer or optics to measure displacement; Use strain gauge; The premise is that the displacement caused by the stiffness of the equipment itself is linear with the load, which should be satisfied in most cases. The stiffness of the equipment can be calculated by the elastic stage of the load displacement curve obtained from the effective experiment + the elastic molus of the material

5. Can't see clearly, can you send a clear picture

6. After the node load is applied, the structure displaces
there are node stiffness matrix, node displacement and node load in the structural stiffness equation. If we know two of them, we can calculate the third? It is suggested to read the textbook of finite element or computational mechanics.

7.

I = EI / L, e: molus of elasticity, I: moment of inertia of section, l: effective length of column

linear stiffness refers to the ability of a material or structure to resist elastic deformation. It is the characterization of the difficulty of elastic deformation of material or structure. The stiffness of a material is usually measured by the molus of elasticity E

in the macro elastic range, the stiffness is the proportional coefficient of the load and displacement of the part, that is, the force required to cause the unit displacement. Its reciprocal is called flexibility, which is the displacement caused by unit force. Stiffness can be divided into static stiffness and dynamic stiffness

< H2 > extended data:

in nature, animals and plants need enough stiffness to maintain their shape. In engineering, some machinery, bridges, buildings, aircraft and ships are unstable e to insufficient structural stiffness, or catastrophic accidents such as flutter occur in the flow field

Therefore, in the design, it is necessary to ensure that the structure has enough stiffness according to the requirements of the code. But the requirement of stiffness is not absolute. For example, the stiffness of the spring in the spring scale depends on the weight range of the object being weighed, while the stiffness of the cable is required to be appropriately reced on the basis of ensuring sufficient strength

the important significance of studying stiffness is that the distribution of stress and strain in the body can be determined by analyzing the stiffness of each part of the body, which is also one of the basic research methods of solid mechanics

8.

The correlation coefficient in Excel can be calculated by correl function

assume that the two groups of data are A1: A7 and B1: B7, and enter the formula = correl (A1: A7, B1: B7) in C1

The

Corel function syntax has the following parameters:

Corel (array1, array2)

array1. The first set of numeric cell ranges

array2 is required. The second set of numeric cell ranges

where x and y are the sample mean average (array1) and average (array2)

9.

The methods are as follows:

1. use extensometer or optics to measure displacement
   

2. use strain gauge
   

3. the premise is that the displacement caused by the stiffness of the equipment itself is assumed to be linear with the load, which should be satisfied in most cases. The stiffness of the equipment can be calculated by the elastic stage of the load displacement curve obtained from the effective experiment + the elastic molus of the material, and then the displacement contributed by the equipment along with the load change can be obtained through this stiffness. The displacement can be subtracted from the load displacement curve obtained by you, so that the rest is the load displacement curve of the material, and then converted into the stress-strain curve< br />