Plastic strain measurement

Strain measurement of plastics

Plastics are avaialble in many kinds and common in low elasticity, low heat-conductivity and large linear expansion coefficient. For plastics, GF series gauges are used. In strain measurement of low elastic materials, the thinner the specimen's thickness, the smaller the srain sensitivity apparently becomes. This phenomenon is called strain gauge stiffening effect, and the smaller the elastic modulus of specimen, the larger the stiffening effect is, and also the thinner the specimen is, the larger the effect becomes.

Features of GF gauges

A special turn-tab with looped ends to easily get sensitivity to low elastic materials is adopted for the gauge grid. The sensing grid is aligned to minimize the influence of Joule's heat.

Strain gauges GF series 
Leadwire integral gauges are produced to order.
Adhesives CN
Coatings A-862-B (N-1)

About hard-to-bond materials

In general, plastic materials such as fluorinated resin, polyethylene and polypropylene can not be adhesive-bonded. However, special chemical treatment makes bonding possible. As the adhesive is CN only, the test temperature range is restricted to the operating temperature range of the CN adheisve.

Treatment with the following chemicals makes bonding with CN ahdesive possible.

Plastics Chemicals (Primer)
Fluorinated resin Tetraechy treatmen (Junkosha Inc.)
Polyethylene Aron polyprimer (TOAGOSEI CO., LTD.)
Polypropylene Aron polyprimer (TOAGOSEI CO., LTD.)