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A comparison of sound radiation behavior of plate in air medium with attached discrete patches/point masses having different thickness variations with different taper ratio of 0.3, 0.6, and 0.9 is analysed. Finite element method is used to find the vibration characteristics while Rayleigh integral is used to predict the sound radiation characteristics. Minimum peak sound power level obtained is at a taper ratio of 0.6 with parabolic increasing-decreasing thickness variation for plate with four discrete patches. At higher taper ratio, linearly increasing-decreasing thickness variation is another alternative for minimum peak sound power level suppression with discrete patches. It is found that, in low frequency range, average radiation efficiency remains almost the same, but near first peak, four patches or four point masses cause increase in average radiation efficiency; that is, redistribution of point masses/patches does have effect on average radiation efficiency at a given taper ratio.

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In this paper ductile fracture of low carbon high strength steel is estimated following the phenomenological approach of continuum damage mechanics (CDM) evolved by Lemaitre. This assumes damage, corresponding to void growth and their coalescence during large deformation, to be isotropic and ductile in nature. The CDM formalism allows estimating the ductile behavior by a damage variable D. This is evaluated from elastic modulus degradation measurement of uniaxial tensile tests with loading–unloading cycles. The result obtained in terms of DC, the critical value of damage, is found to be 0.44. This gives a measure of ductile fracture from the CDM approach. Respective average D values corresponding to every elastic modulus degradation estimate are used for simulation of ductile behavior of the material. The simulation result closely approximates the experimental flow curve up to about 15 % of strain with minor deviation beyond this strain level up to fracture. The method shown provides a way to evaluate ductile behavior of a material conveniently.

In this paper, the ductile behaviour of two different low carbon steels, C-Mn-440 and interstitial free high strength (IFHS), is presented using a continuum damage mechanics (CDM)