Single drum type mechanical property stretching test method and device for plastic film

Abstract

The invention discloses a single drum type mechanical property stretching test method and device for a plastic film. The device mainly comprises a computer, an electric heating system, a transmission mechanism, a stretching mechanism and a restraining device. During the stretching process of the plastic film between the transmission mechanism and the stretching mechanism, scale distance l of the plastic film is unchanged; it is given that the outer ring linear velocity, the stretching speed, the instantaneous area, the instantaneous linear strain, and the strain of the plastic film wound on a main shaft are v, v, S, epsilon and sigma, respectively; a tension sensor is arranged on the main shaft of the stretching mechanism; according to the formulas in the description, v and l of the plastic film are both constants in the stretching process, so that epsilon is a constant; the stretching sensor transmits the acquired tension and strain information of the plastic film to the computer, and the computer performs data processing.

Description

technical field [0001] The invention relates to a mechanical measurement technology of plastic films, in particular to a single-roller tensile test method and device for plastic films. Background technique [0002] plastic film at a constant strain rate The true stress σ and true strain ε in the deformation process are an important mechanical parameter of the plastic film. On the traditional plastic film tensile testing machine, the constant strain rate cannot be guaranteed at a constant tensile velocity V. However, the stretching at a constant strain rate can only be achieved through the following two methods: 1. By calculating the V under the condition of a constant strain rate, the operator manually adjusts V at intervals to achieve an approximate constant strain rate. Tensile test; 2. Additional program control equipment on the ordinary tensile testing machine to change V at any time for automatic control. The accuracy of the above two methods is not high, especia...

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Problems solved by technology

The accuracy of the above two methods is not high, especially when V is large, the error will be too large

In addition, there are difficulties in testing the high-temperature mechanical properties of plastic films: after the glass transition temperature Tg, the film will become more and more difficult to clamp because the material becomes soft and sticky

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