STABILITY ANALYSIS OF A CAPACITIVE FGM MICRO-BEAM USING MODIFIED COUPLE STRESS THEORY

Based on the Modified Couple Stress Theory, a functionally graded micro-beam under electrostatic forces is studied. The FGM micro-beam is made of two materials and material properties vary continuously along the beam thickness according to a power-law. Dynamic and static pull-in voltages are obtained and it is shown that the static and dynamic pull-in voltages for some materials cannot be obtained using classic theories and components of couple stress must be taken into account. In addition, it is shown that the values of pull-in voltages depend on the variation through the thickness of the volume fractions of the two constituents.