Designing Multifunctional Polymer Composite for Disaster Monitoring

In this study, a piezoresistive structural sensor (multifunctional material) was developed and a cantilever beam element with varying cross sections was designed and tested to measure low pressures for use during disaster events such as hurricanes. The piezoresistive structural polymer composite material developed in this study had a compressive strength of over 65 MPa (9425 psi), considered to be stronger than the standard construction materials. Also the piezoresistive material was over 30 times more sensitive than the resistance strain gages in detecting strain. The compressive stress-strain relationship of the polymer composite was modeled using a non-linear relationship. The constitutive behavior of the piezoresistive material was modeled using incremental nonlinear stress-resistivity relationship. The structural response of the cantilever beam with varying cross sections was analyzed using the finite element method. With the newly developed cantilever beam element it was possible to magnify the piezoresistive response and detect applied pressure as small as 1.4 kPa (∼0.2 psi) with a change in electrical resistivity of 0.5%.