Natural Frequencies of GFRP Beam Under Tensile Axial Loads

The influence of axial tensile force on the bending natural frequencies and vibration modes of the beam from glass fiber reinforced polymer (GFRP) was studied. The composite specimen was made using the hand lay-up method. A Polytec PSV400 scanning laser vibrometer was used to determine the natural vibration frequencies and vibration modes. The experiment was carried out using Z100 testing machine in tension and compression. Using hydraulic grips, the specimen was subjected to tension with a prescribed force, after which the frequencies of natural vibrations and vibration modes were determined. To verify the experimental results, a numerical calculation was performed by the finite element method (FEM) using the ANSYS software. The FEM model was developed taking into account the specimen of the specimen fixation in the testing machine. The elastic properties of the composite material were determined by means of the identification procedure of material properties. Using this method, nine parameters of the composite material were determined, which were subsequently used in the numerical calculations to verify the results of experiments on natural vibrations of the specimen subjected to axial tensile load. The experimental results were close to the calculated ones demonstrating the increase of the natural frequencies with increase the tensile longitudinal force.