Analysis of 3 different tear strength testing methods
At present, Fabric There are mainly three kinds of testing methods for tearing strength, namely, trouser method, trapezoidal method and impact pendulum method. Textile Tear tester, fabric tear tester, fabric tear strength machine and so on. Aim at Three What are the principles of different testing methods? What is the difference in the operation of the experiment?
The principle of impact pendulum tearing is:
The sample is fixed on the clamp, and the sample is cut into one incision to release the pendulum at the maximum potential energy position. When the movable fixture is away from the fixed clamp, the sample is torn along the direction of the incision, and the work done by the length of the tear fabric is converted into torn force.
The two legs of the trousers sample are clamped to make the sample cut line straight between the upper and lower clamps. An instrument is applied to apply tension to the direction of the incision, recording the tearing strength until the tear is broken to the specified length, and calculating the tear strength according to the peak value drawn on the curve drawn by the automatic plotting device or by the electronic device.
Trapezoidal tearing principle:
Draw a trapezium on the specimen and clamp the two non parallel edges on the trapezium with the clamp of the strength tester. A continuous increase of force is applied to the specimen so that the tear can propagate along the width of the specimen and the average maximum tear strength is determined.
One The tearing strength test procedure of pendulum method is as follows:
Press the pendulum stop button and release the pendulum. When the pendulum swinging back, hold it so as not to damage the position of the pointer, and read the torn strength from the measuring device scale or digital display, the unit is Newton. According to the type of instrument used, the data read may need to be multiplied by the corresponding coefficient specified by the manufacturer to be expressed in the form of Newton. The inspection result should fall on the ruler. 15% ~ 85% At least repeated trials in each direction. Five Second time.
See whether the tear is along the direction of the force and whether the yarn slips from the fabric rather than the tear. The test that satisfies the following conditions is an effective test: A. The yarn is not slipping from the fabric. B. The specimen did not slip from the fixture. C. Tear completely and tearing all the time. 15mm If the test results are not satisfied in the wide range, they should be eliminated. Five In block specimens Three Block or Three If the block is deleted, this method is not applicable.
Two The trouser method tearing strength test steps:
Turn on the instrument. 100mm/min The tensile rate is torn to the end mark of the sample. Record tear strength. If you want to get the tear trail of the specimen, the tear strength and tear curve of each specimen in each direction can be recorded by recording instrument or electronic recording device. If the peak value is derived from high density fabric, there should be manual number. The ratio of the rate of travel to the drawing speed of the recording paper should be set to 2:1 To see whether the tear is in the direction of the applied force and whether there is a slip of the yarn from the fabric instead of being torn. The test that satisfies the following conditions is an effective test: A. The yarn is not slipping from the fabric. B. The specimen did not slip from the fixture. C. The tear is complete and the tear is carried in the direction of force.
The test results that do not meet the above requirements should be eliminated. If Five Among the specimens are Three The test results of one or more samples are excluded, and this method is not applicable to the sample. If the agreement is increased, it is better to double the number of samples and to report the results of the agreement.
Three Trapezoidal tearing strength test steps:
Set the distance between the two tongs. Twenty-five + One ) Mm The tensile speed is 100mm/min Choose the suitable load range to make the tear strength fall to the full scale. 10% ~ 90% Between them, install the specimen and clamp the specimen along the non parallel sides of the trapezoid, so that the incision is located in the middle of the two clamps, the trapezoid short edge is kept tight, the long side is in the crease state; the instrument is started, and the tear strength is recorded automatically with the automatic recording instrument. If tear strength is not carried along the incision line, no record is made.
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