Parametric instability analysis of pultruded composite columns under dynamic loading

As demand for designing light weight structural members are increased, the application of open or closed pultruded composite thin-walled cross section is growing significantly. By applying axial harmonic time-changing compression load to pultruded column, out of plane large deformation might be occurring. The equilibrium method of the main differential equation of column under harmonic load will be achieved. By obtaining the differential equation of pultruded column, the dynamic instability region of pultruded column is calculated using the classical lamination theory (CLT). This region shows what amplitude and frequency of dynamic compression load leading to buckling of the pultruded column. The results display that by time-varying loads with amplitude lower than member's Euler buckling load, the instability could occur because of the load frequency almost twice of the natural frequency. As an extensive parametric studies it was concluded that the laminate sequences with layup [۰,۹۰,+۴۵]s results in more stable column among other layups. Moreover it will concluded that by increasing frequency of dynamic load, the critical dynamic amplitude of column will increase.

کلیدواژه ها:

Parametric instability ، Pultruded composite column ، Bolotin's first order Method ، Classic Lamination Theory ، Euler buckling