PSI - Issue 60

S.K. Pandey et al. / Procedia Structural Integrity 60 (2024) 665–677 S. K. Pandey/ Structural Integrity Procedia 00 (2023) 000 – 000

676 12

Fig.13. Comparison of experimental and FEA load displacement curves.

6. Conclusion

Some of the important observations and conclusions from the study are as follows.  Incident pulse duration is proportional to the length and material of striker, which is equal to the duration of time to travel the wave in to the double length of striker.  Amplitude of incident pulse depends on velocity of striker and Young’s modulus of elasticity of material of incident bar.  Reflection and transmission of wave depend upon the material property of specimen and the extent of mismatch in impedance of incident bar and specimen.  In case of pure elastic deformation of specimen, no wave reflects when the cross section of the specimen is same as that of incident and transmission bars.  In case of plastic deformation of the specimen, the transmitted wave increase with time due to strain hardening in the material and reflected wave decreases with time as sum of amplitudes of reflected and transmitted waves at any instant must be equal to that of incident wave.  Since stress in the specimen is proportional to the transmission signal, hence stress and load in specimen increases (i.e., due to strain hardening) with time.  The strain rate decreases with time since it is proportional to the reflected signal as presented in Eq. (15).  Radial offset between the striker and specimen doesn’t affect the signals as obtained from FE analysis results.  The analysis and experiment have been performed with different shapes of specimen cross section such as circular, rectangular and triangular, keeping same cross section area. It was observed that shape of cross section doesn’t affect the strain signals as long as the area remains same.