Piezoresistive anisotropy of percolative granular metals
  The piezoresistive response of granular metals under uniaxial strain is strongly dependent on the concentration of the conducting phase. Here we show that the piezoresistive anisotropy is reduced as the system approaches its percolation thresold, following a power law behavior in the critical region. We propose a simple relation between the conductance and the piezoresistive anisotropy which could be used in relation to real materials and notably to the thick film resistors. 
C. Grimaldi, P. Ryser, S. Straessler