Testing puncture resistance

Figure 8,10 illustrates the general configuration for testing a film s puncture resistance. We can perform this test in a number of ways. The probe may be attached to the crosshead of a universal testing machine, similar to the one illustrated in Fig. 8.3. We drive the probe down through the film at a constant speed, while recording the force. Alternatively, we can perform an impact puncture test, in a similar fashion to impact plaque testing.

Table 2. Results of dynamic puncture resistance tests...

Puncture resistance BS 4812 1972 (93) ISO 3036. A triangular pyramid puncture head is attached to a pendulum. It is released to swing onto a test piece. The energy required to force the puncture head right through the piece, i.e. to make the initial puncture and to tear and bend open the test piece, is measured. 

There are two European standards that spedly a method of testing cut resistance of a fabric against sharp objects. These are BS EN 388 2003 and BS EN ISO 13997 1997. - BS EN 388 2003 was developed specifically for gloves and it details the test methods for measuring abrasion resistance, blade cut resistance, tear resistance, and puncture resistance. BS EN ISO 13997 1997 was developed for any protective clothing and specifies the test method for the determination of resistance of a fabric to cutting by sharp objects. 

American National Standard provides guidance for selecting suitable gloves that will protect workers and assist employers in compliance with OSHA Regulation 29 CFR 1910. The standard covers glove selection criteria in specific categories related to testing and performance properties in chemical and industrial applications, such as cut method puncture resistance abrasion... 

In many film applications the product is subjected to puncture or impact loads. These types of loads are applied perpendicular to the plane of the film. Therefore, the stresses act biaxially (in both the machine and transverse directions simultaneously) and are not represented well by a uniaxial test. Impact resistance tests are designed to biaxially load the film to measure its energy absorbing capability. 

The force required to create a short through a separator due to mix (electrode material) penetration defines mix penetration strength. In this test, force (with a Vi.-inch diameter ball) is applied on the positive electrode/separator/negative electrode sandwich and the force at which the mix penetrates through the separator and creates an electronic short is called mix penetration force. Mix penetration strength is used to indicate the tendency of separators to allow short circuits during battery assembly. The mix penetration resistance test is more closely related to particle penetration resistance compared to puncture resistance [45]. 

Gangstad and Snell (1943) have made detailed use of regression techniques in a study of the texture of sweet com. Three standard varieties, one experimental variety, and the parent inbreds were tested with a puncture meter to measure resistance (in grams) in relation to dry weight and maturity (days after pollination). Dry weight is a reliable index of maturity for sweet com, and on this basis it was postulated that puncture resistance should be a valid measure of some function of dry weight and days after pollination (maturity). 

The second equation listed for each of the four hybrids (Table XLV) is the result of the simultaneous solution of the equations for the component varieties. This combination was made to test the hypothesis that the resulting equation would approximate the relationship between mean puncture resistance and the product of days after pollination and dry weight, thereby offering a method for predicting the results of the cross in these terms before the cross is made. Comparison of the pairs of regres-... 

The static puncture test is described in EN ISO 12236 Geotextiles and Geotextiles-Related Products - Static Puncture Test. A cylindrical stamp (50 mm in diameter) is pressed through a clamped geomembraue disk of 150 mm fiee diameter at a speed of 50 mm/min. Thereby the resistauce to quasi-static puncture by a small, sharp edged object is determined. The maximum force required (puncture resistance) is the test parameter. The 2.5 mm thick HDPE geomembianes typically reach values > 6000 N. 

ASTM D4833 2000 Standard Test Method for Index Puncture Resistance of Geotextiles, Geomembranes, and Related Prodncts... 

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