Direct measurement of residual strains in CFRP-tungsten hybrids using embedded strain gauges

Publication date: 5 August 2017
Source:Materials & Design, Volume 127
Author(s): M. Kanerva, P. Antunes, E. Sarlin, O. Orell, J. Jokinen, M. Wallin, T. Brander, J. Vuorinen
In this work, the implementation of fully embedded electrical resistance strain gauges was studied for a hybrid material system. The samples were laminated using carbon-fiber-reinforced plastic (CFRP) and tungsten. The raw materials and the adhesive used for bonding strain sensors were characterized to understand the overlapping sources of non-linearity and error. Test-specific correction functions for a thermal output were determined for the strain gauge measurement and comparative fiber Bragg grating (FBG) measurement. The strain accumulation in the fiber direction during the cool-down phase for different cure cycles was analyzed using a finite element simulation. According to the results, embedded electrical resistance strain gauges can be used to determine the thermal expansion of a hybrid laminate with acceptable accuracy when thermal output is compensated for using case-specific correction functions accounting for measurement setup, the stiffness of the gauge bonding adhesive, and embedding.

Graphical abstract

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