Dynamic Stability Study of Pultrusion Composite Members under Follower Force

Planar dynamic behavior of laminated pultrusion composite beam members with distributed mass under non–conservative follower force is investigated in this study. Non–prismatic and non–homogenous cases of pultrusion composite beams in their length domain are considered in analytic closed form solution of the problem. The pultrusion composite beams are composed of laminated elements with fiber–reinforced lamina lay–up configurations. Variation of homogeneity and section geometry in pultrusion beam length can affect mainly the dynamic stability status of the structure under follower force excitation. Follower force case can be frequently seen in spacecraft structures and aerospace applications when load changes its direction due to structure lateral vibrations. As shown in this investigation, the main mode of dynamic instability of such structures is flutter or divergence that depends on stiffness and mass distributions of composite member. Stiffness of pultrusion members is modified by their longitudinally varying geometrical properties and laminate layout of section elements. Results of current study can help the designer to shift the dynamic instability mode of beam by changing the distribution of mentioned parameters. Solution of presented mechanical problem is done using an analytical approach. Sturm–Liouville eigenvalue theorem combined with kernel integral transformation method is used to obtain the modal solution of equilibrium. The stability zones of the member are stated as results