Unilateral plastic film stretching test method and device based on constant strain rate

Abstract

The invention discloses a unilateral plastic film stretching test device based on a constant strain rate. The unilateral plastic film stretching test device comprises an electric heating system, a driving mechanism, a stretching mechanism and a computer, wherein the electric heating system comprises a thermostat; the stretching mechanism is arranged in the thermostat and comprises a bottom plate, and a cylindrical roller, a bracket, a rolling bearing, a vertical slot, a guide rail, a clamp and a pressing plate which are arranged on the bottom plate; two ends of the cylindrical roller are arranged on the bracket through the rolling bearing; the vertical slot is formed in the guide rail through a slide block and can slide along the guide rail; the clamp is arranged in the vertical slot; a semi-cylindrical groove is formed in the clamp; one side of the pressing plate is provided with a semi-cylindrical boss which is matched with the semi-cylindrical groove and is used for fixing a plastic film sample; a spindle of the roller penetrates through the thermostat body and is connected with the driving mechanism; and a tension sensor is arranged on the spindle and is connected with the computer. The device is easy, convenient and feasible in technical means and has positive technical effect and high popularization and application value.

Description

technical field [0001] The invention relates to the technical field of mechanical measurement of plastic films, in particular to a uniaxial tensile test method and device for plastic films based on a constant strain rate. Background technique [0002] Plastic film (thickness ≤ 0.5mm) at constant strain rate The true stress σ and true strain ε in the deformation process are an important mechanical parameter of the plastic film. [0003] On the traditional plastic film tensile testing machine, the constant strain rate cannot be guaranteed at a constant tensile velocity V. However, stretching at a constant strain rate can only be achieved by the following two methods: [0004] 1. By calculating the V under the condition of constant strain rate, the operator manually adjusts V at regular intervals to achieve an approximate constant strain rate. Stretching test. [0005] 2. Add program control equipment to the ordinary tensile testing machine to change V at any time for a...

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Problems solved by technology

[0006] The disadvantage of the above two methods is that the accuracy is not high; especially when V is large, the error will be too large

In addition, the following difficulties exist in the high-temperature mechanical performance test of plastic films: after the glass transition temperature Tg, the material becomes softer and stickier, and it becomes more and more difficult to clamp the material

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