• Composite Specimen
• Dynamic
• Macro Fiber Composite
• Nonlinear
• Piezoelectric actuator
• Transient Structural

The thesis presents the nonlinear dynamic behavior of composite fiber beam with Macro Fiber Composite glued onto them. The composite material employed are made of thin Carbon/Epoxy or Glass/Epoxy prepreg fabric with 0.25 mm thickness. The piezoelectric patches employed here are Macro Fiber composite (MFC) with 0.3 mm thickness. The Macro Fiber Composites (MFC) are glued onto the surface of the composite material on top and on the bottom. High temperature wires were soldered on to the piezoelectric patch to provide them with electric voltage excitation. MFC is composed of ceramic fibers that can bend or flex when a current is applied to it-much like a muscle. The Macro Fiber Composite also generates a current when it is vibrated or flexed, giving us the ability to use the MFC as a next-gen vibration detector as well.
The aim of the project is to study the transient structural response of the hybrid structure. The transient structural response has been studies using the FEM software ANSYS. A flexible method is developed and implemented in this work based on ANSYS Parametric Design Language. In this project, composite panel is modeled with 3D 20-node solid element and the Macro Fiber composite is modeled with a 3D 20-node coupled-field solid element. The geometry for the hybrid structure is designed keeping in mind the bending and torsional specification of the MFC provided by the manufacturer. The mesh for the structure is an adaptive mesh which gives emphasis on the edges and connecting nodes, which basically refines the element size close to the edges to a minimum and rest of the structure as adaptive.
The specimens used for this project were specially manufactured from the Smart Material Corp. (SMC) developed within the European Collaborative project titled “FutureWings”. The composite fiber beams have four different fiber orientations. The specimens were tested for bending and torsion tests with different values of voltage excitations and impulse loads. These results are validated with the experiments carried out on the specimens in the Aerospace Department laboratory. The transient study of the structure allowed us to evaluate the real modes of vibration of the hybrid structure which were then compared with the result obtained from the experimental analysis through the use of Fast Fourier Transform(FFT) and Frequency Response(FR) of the system. The study also highlights the stiffening/softening effect of the Piezoelectric actuators on the specimen dynamic response.