Explanation of test machine terms

Testing machineThe scope of use is becoming more and more widespread, and mastering necessary professional terms is the basic requirement of every operator. The following are professional terms about test machines explained to customers by engineers from Jinan Hengsi Shanda Instrument Co., Ltd.:

Volume elastic modulus

The ratio of stress and volume transition when data is subjected to axial load is called the volumetric elasticity modulus. The volumetric elastic modulus and elastic modulus are revealed by the inferior equation (E) and Poisson's ratio (r) Relationship: Volume elastic modulusK=E/3(1-2r).

S-Npicture

In the experiment, use a set of the same samples, stress (S) The number of cycles relative to the sample to the time of failure (N) curve graph calledS-Npicture. existS-NThe curve in the figure is composed of a set of data points that determine their deficit life under different alternating stress. Stress coordinates can represent stress amplitude, stress or small stress. Coordinates of a certain logarithmic standard are often used to reveal performanceN, sometimes used to reveal performanceS.

Impact strength

In impact experiments, the energy required for the sample to break under impact loads. Others can also be called impact energy, impact value, impact resistance, and energy reception value. It is a target value for data toughness.

Elongation

The amount of data ductility measured in tensile experiments. It is the gauge increment (measured after the breakage) divided by the original gauge length. The higher the elongation, the higher the ductility. It is impossible to use elongation to guess the characteristics of data when it receives sudden loads or repeated loads.

Impact energy

Shock experimentIn this case, the energy required for the part to break under impact loads. Other titles include impact value, impact strength, impact resistance, and energy reception value.

Submission intensity

Without causing plastic deformation, the stress value that the data can accept becomes the yielding strength of the data. Under this stress, the data is subjected to the rule forever deformation of the inevitable amount, and this stress is also an approximation of the elastic limit of the data practice. The premise yield strength can be measured through stress-strain diagrams. It is the stress value corresponding to the intersection of the stress-strain curve and a line parallel to the local line in the stress-strain curve. (called the intensity of rules of submission) Regarding metals, the rules of the world are transformed forever into0.2%, that is, the rule line and0The sub-intersection point of the stress axis is0.2%Strain. Regarding plastic, this strain value is taken in the world.2%.

Stiffness

It refers to the amount of plastic bending resistance. It also includes two characteristics: plasticity and elasticity, so the stiffness is only the apparent value of the elastic modulus rather than the true value (ASTMD-747specification).

Flexibility of elongation

The strain when the data yields to the intensity is a representation of the data ductility.

Rigid modulus

It means that the strain of the sample receiving shear or changing the load is a function of stress, and the rigid modulus is the transition rate of stress by strain. It is the elastic modulus measured in the experiment, that is, the elastic modulus in the experiment and the shear experiment. Apparent rigidity modulus is a way to change the plastic stiffness measured in the experiment (ASTMD-1043). The reason why it is called "appearance" is that the sample has exceeded its proportional limit and can deflect. The calculated value cannot be as good as the true elastic modulus representing the elastic limit of the data.

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