Study On The Composites For Backing Material Of Load Cell Strain Gage

Stain gage load cells are diffusely used in the mechanical measurements with high precision. At present, load cell design, manufacture and test in china, especially the strain gage backing material were laggard a lot. A study of milled glass fiber reinforced composites used as the strain gage backing material is present in this paper, which made it suitable more well for the demands of load cell. The process of prepare for the composites and the microstructure, mechanical and thermal properties were studied thoroughly by means of experiments and analysis. The main results are summarized as follows:First, formulation tailoring and curing process of epoxy resin adhesive have been studied, and the peel strengths were tested. The curing temperatures are obtained following the result of curing reaction heat flow tested by DSC. The results showed that the modified epoxy resin was satisfied, and can stick well to constantan alloy. The tests of resistance to hydrothermal ageing showed that the adhesive has excellent resistance to weathering.Second, after lots of experiments for the process of glass fiber surface modified, we primely avoided the glass fiber reunite with each other, and successfully prepared the glass fiber reinforced composites film. Film microstructure is investigated by scanning electronic microscopy (SEM). The micrographs showed that glass fiber distributed in epoxy resin with good dispersity, and interweaved with each other homogeneously.Third, the mechanical properties were conducted by tensile test, and analyzed the relationship between the length, content, coupling agent levels and the tensile strength, tensile modulus of composites films. The result showed that the optimum formulation was the contents of long milled glass fiber 20.0wt% and coupling agent KH-550 1.0wt%.Forth, the glass transition temperature, creep and strain recovery of strain gage backing materials were determined by dynamic mechanical analysis(DMA) and differential scanning calorimetry(DSC). The influence temperature and stress imposing on creep were also discussed respectively. Glass transition temperature, creep and strain recovery of five different composites films were compared. The...