Analysis of Experimental Method of Drop Hammer Tear Tester

The tear strength test of the fabric is an important indicator of the strength of textiles. This test is a very important experiment. There are several methods for the strength test of textiles. Currently, there are the trapezoidal method and the tearing method with a drop hammer. Testing machine, one-tongue method A, one-tongue method B and other methods, here the engineers from Standard Group (Hong Kong) Co., Ltd. Briefly explain to you the experimental method of drop hammer crack testing machine.

1. The purpose and requirements of the experiment
Master different tear strength test methods, tear characteristics and principles of fabrics, and understand the reasons and scope of the differences in the results of different tear strength measurements.

II. Experimental instruments and utensils
Fabric strength and drop weight fabric tear tester, ruler, pen, scissors, tweezers.

3. Sample
A piece of woven cloth

4. Crack tester for a drop hammer
1—work table 2—support arm 3—fan-shaped drop hammer 4—pivot point 5—fixed cloth clamp 6—moving cloth clamp 7— Block plate 8 - scissors 9 - pointer 10 - on the iron plate of the needle block, there is a solid cloth clip 5 on the side of the support arm and a moving cloth clip 6 and 7 are spring clips on the fan-shaped drop hammer. 8 is a knife used to cut the sample. A pointer 9 is again protruded from the shaft sleeve of the fan-shaped drop hammer, and due to the friction effect between the shaft sleeves, the pointer can swing along with the fan-shaped drop hammer. However, in the way the pointer advances, because it is blocked by the needle-holding iron plate 10 fixed on the workbench, friction and slip occurs between the bushings, and the pointer 9 cannot swing counterclockwise, so that he can indicate the potential energy orforce of the crack size.
1. Sample preparation: The cloth sample cutting and the number of strips are the same as single tongue method A, and the sample is shown in Figure 40.4.
2. Turn the fan-shaped drop hammer 3 clockwise to be blocked by the spring retainer 7 on the workbench 1. At this point, the two working surfaces of the cloth clamps 5 and 6 are exactly aligned.
3. Clamp the strip sample in the two cloth clamps 5 and 6 and align the jaws of the cloth clamp with the clamp line in the center of the strip sample.
4. Rotate the cutter 8 to cut a single slot of a certain length from the sample.
5. Press the spring stopper 7 to release the brake on the fan-shaped drop weight 3, and the fan-shaped drop weight 3 will fall counterclockwise, and the fabric clip 6 will also fall down, so that the strips are torn to the limit until it rips. Record the tear strength indicated by pointer9. Reset the device. Remove the sample. One test has been completed (if the test strip shifts or the jaw breaks during the test, replace the test strip and repeat).

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