タイトルまたは説明

Strain gauges are usually installed on a surface whether it is for stress analyses or sensor production,without any external force applied to the surface.When environmental temperature changes,the resistance of the strain gauge changes accordingly.This phenonmenon is called the strain gauges thermal output.This thermal output is the result of interactions and superposition of the resistance temperature coefficient of grid materials,the sensiitive grid materials and the linear expansion coefficient.

Common strain gauges often have a large thermal output . Thermal output is the biggest source of errors in static strain measurements,When temperature increases the dispersion and therefore the thermal output value increase.Ideally the thermal output of strain gauges should be zero.To meet this requirement a self-temperature compensating strain gauge is used.

y adjusting the composition ratio of the alloys of the strain gauge sensitivity grid material,and make used of cold rolling and proper heat treatment,the internal crystalline structure of gauge material can be altered in way it will compensate the changes of the material due to temperature change.This way the change in Thermal output can be kept very close to zero and standards for high-precision sensors and stress analysis can be met.

…  Temp. Self-compensation
The hypostasis of Zero Output is the Potential Discrepancy of load cell between two output
terminals, and the Potential rest with the two Electric Bridges resistance. The working Temp. of this
Electric Bridges resistance change as well as the Zero Output of load cell, so this change about the
Zero Output of load cell called Zero Excursion(P).
Why the Electric Bridges resistance will be change when the Temp. change? To strain gauge, it is
affected by its Heat Output. Heat Output is the strain gauge installed on the unfettered specimen, no
force, when the environmental Temp. Changes occur as a chance in its resistance. So the ideal of strain
gauge is the Heat Output approach Zero. This kind of strain gauge is Temp. Self-Compensation Strain
Gauge. But it is opposite speaking to Self-Compensation, this Temp. Self-Compensation Strain Gauge
also have Heat Output, just it is less than others.
We always change the materials of Sensitive Grids and change the Resistance Temp. Coefficients
by heat treatment make to make the Heat Output of strain gauge to approach Zero. We synthesize the
function relations which among Elastomer linear expansion coefficient, Foils linear expansion
coefficient, Resistance Temp. Coefficient and Temperature, with suitable heat treatment to produce
Self-Compensation strain gauge which linear expansion coefficient is 9,*1,*6,*3.
Remark: *1 is suit for alloy steel, Martensite stainless steel, Precipitation
Hardening stainless steel etc.. *6 is suit for Austenitic Stainless Steel etc.. *3 is suit for
Aluminium alloy etc...
…¡.Creep Self-compensation
All metal will bring spring aftereffect, it says when the metal have force in its spring scope, it
distort and will not balance with its load at once, but a little later; after retract the force, it also will not
distort to original state at once, but a little later, it will become the same. So this will show by Positive

Creep that the output signal of load cell increase as the time increase. The output signal also will
Negative Creep, because the fundus and slice will slack (By stated stress will decreased by time), and
the value can be adjusted by change the configuration of Sensitive Grids, the materials of fundus and
produce technics. If the absolute value of Positive Creep is the same as the Negative Creep, then the
Creep of the load cell can Self-compensate to the best. Our company produces different Creep grade
strain gauge to satisfy our clients.

….Elastic Modulus Self-compensation
In elastomer, elastic modulus decrease with the raise of the ambient Temp., and the output of the
load cell increase with the raise of the Temp. We adjust the heat treatment of Sensitive Grids to make
the Sensitive coefficient K decrease with the raise of the Temp., in order to counteract the increase
which brought by the elastic modulus decrease with the raise of the Temp. at last to achieve
Self-compensation,this strain gauge is called Elastic Modulus Self-compensation Strain Gauge. It
synthesize both effects about common strain gauge and Self-compensation elastic modulus, good
stability, low cost, high sensitivity, easy to produce and work, it is also suit for load cell which the
precision grade is 0.*5 or mass production and low cost.