General

The phenomenon of the fabric being pulled apart under such concentrated loads is often referred to as tearing. The tear strength of a fabric is an important indicator of the quality of textiles. The instrument used to measure this indicator is called Elmendorf Tearing Tester. 

Calculation principle:

The tear strength measured by Elmendorf Tearing Tester was calculated from the work consumed when the sample was torn, and it can be said to be the average strength of the fabric tear. The work consumed during the tearing of the sample is the conversion of the potential energy of pendulum hammer. The potential energy consumed by the pendulum hammer before and after work can be divided into two parts: the work consumed during the tearing of the sample and the work consumed by all other resistances in the process. The work consumed for tearing the specimen is the product of the average tearing force and the work stroke; the work consumed by the resistance is the product of these resistance moments and the swing angle of the pendulum hammer. As shown in the figure, the solid line is the initial state, and the dotted line is the position at the end of the work.

The formula for the principle of action is

               m g ( h1 - h2 ) = FS +Mα

               Or  m gΔh = FS +Mα (1)

               In the formula:  

               m--- Pendulum hammer mass, kg;

               g--- Gravity acceleration, m / s2 ;

               Δh--- Height difference of gravitational center of

the pendulum hammer before and after work, m;

               F --- Average tearing force of sample, N;

               S --- work stroke of tearing the sample, m;

               M --- Resistance moment, N·m;

               α--- Pendulum hammer rotation angle.

Machine recommendation:  AG11 Elmendorf Tearing Tester

It is used to measure the tear strength of materials such as fabric, paper, plastic cloth, film, electrical tape, and metal foil.