OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 25 No. 3 2023 Aimil private limited (Bangaluru, India) with position accuracy 0.001 mm and speed accuracy 0.005 %. The test specimen was first clamped between the UTM clamps and then subjected to an increasing load at a tensile rate of 3 mm per minute until the specimen was broken. Five different specimens were cut from five different layered CMs and used for tensile tests to ensure test reproducibility and take into account average values. The flexural test was performed on the same digital universal testing machine (UTM) on specimens with tufted Munya fibers in accordance with ASTM D790 specifications. For each combination, five specimens, 150×15×3.5 mm, were considered and average results were taken to ensure test reproducibility, with the flexural test speed matching that of the tensile test. The characteristics of free vibrations are analyzed using the experimental setup shown in fig. 3a and 3b, respectively, to estimate the initial six natural frequencies and the corresponding damping factor using the frequency response and using the fitting circle method, respectively. Based on mass and stiffness matrix resonance response, the six visible resonance peek are considered in this study. The major aim of conducting free vibration test is to see the application of this composite as structural material or as damping material. The test specimen was in the form of a Ta b l e 1 Composite composition (by Volume) Specimen No. Material Used Nomenclature Specification Volume Ratio 1 Neat Resin, dm3 NR AW106 1 2 Hardener, dm3 HV953 1 3 Particulate Munja, % PC - 20 4 Unidirectional Munja, % UDC - 20 5 Short & Random Munja, % SRC - 20 Fig. 1. Compression moulding machine Fig. 2. Fabrication process
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