http://localhost:8081/jspui/handle/123456789/121 Fri, 15 May 2026 11:33:02 GMT 2026-05-15T11:33:02Z http://localhost:8081/jspui/handle/123456789/20895 Title: MODELING OF SUB-INTERFACE CRACK IN PIEZOELECTRIC BI-MATERIAL USING XIGA Authors: Kushwaha, Aman Abstract: Due toqtheir strongqpiezoelectric,wdielectric, andapyroelectric properties,qpiezoelectric ceramics have.become popular.materials.for a wide range of electrical and mechatronicq systems. Piezoelectric ceramics, on the other hand, are brittle and crackable at all scales, from electric domains to devices. In piezoelectric ceramics, imperfections such asqdomain walls,qgrain.boundaries, faultsqand pores,qimpurities andqinclusions, and so on exist. The imperfections generateqgeometric,qelectric, thermal, andqmechanical discontinuities, resultingqin high stressqand electricqfield concentrations, which can lead toqcrack initiation, crackqpropagation, partialqdischarge, andadielectric breakdown,qfracture, andqfailure. Because the reliability of theseadevices is so important, there has been a lot of interest in understanding theqfracture andqfailure characteristics of these materials. This article provides an overview of the fracture behaviour of piezoelectric materials using theoretical, experimental, and numerical methodologies. It evaluates piezoelectric materials' fracture behaviour in a combined mechanical and electrical loading (electro-mechanical) environment. It also includes the present stage of computational progress for piezoelectric modelling that has been achieved. The dissertation discusses the fundamentals of the freshly invented XIGA approach. The extended finite element technique (XFEM) and isogeometric analysis are combined in XIGA, a numerical method (IGA). The XIGA technique has proven to be superior to other recent methods because it creates a close link between computer-aided design (CAD), geometry, meshing, and analysis. Tue, 01 Jun 2021 00:00:00 GMT http://localhost:8081/jspui/handle/123456789/20895 2021-06-01T00:00:00Z http://localhost:8081/jspui/handle/123456789/20894 Title: MODELING AND ANALYSIS OF NONLINEAR ENERGY SINK FOR SHOCK ISOLATION Authors: Chauhan, Akshay Abstract: Vibration absorbers are widely used with several machines and structures to reduce the unwanted vibrations in the system. Most of the vibration absorbers used are linear and have the capacity to suppress the vibrations to a great extent. But the linear vibration absorbers have their own disadvantages, mainly the requirement of tuning them over time. Thus, a non-linear vibration absorber or non-linear energy sinks are being studied widely. The objective of this study is to model a Nonlinear Energy Sink (NES) for a simply supported beam excited by a shock load. Introducing the pure non linear stiffness in the NES is the main challenge faced while modelling it. Thus, a method to overcome this challenge is introduced and proved by doing simulation of the model using ANSYS Workbench. Then finally its ability to suppress the vibration is shown through a transient response curve of the beam with and without the attached NES. Tue, 01 Jun 2021 00:00:00 GMT http://localhost:8081/jspui/handle/123456789/20894 2021-06-01T00:00:00Z http://localhost:8081/jspui/handle/123456789/20893 Title: DEFORMATION MECHANISM IN ALLOY USING ATOMISTIC SIMULATION Authors: Sharma, Abhinav Kumar Abstract: Aim of this dissertation was to develop an atomistic model to study the effect of irradiation on the deformation governing mechanism of metal or its alloys and evaluating their mechanical behaviour during the shear deformation. In this thesis, efforts were made to study the effect of helium nanobubble on the onset of plastic deformation in a single crystal Ni. The onset of plastic deformation was quantified as a function of the orientation of slip planes with shear force, and configuration of helium nanobubbles. Two sets of configurations were generated for helium nanobubble, one with radius fixed but the ratio of He to Ni vacancy was varied, whereas in another configuration the ratio was kept constant and the radius of the nanobubble was varied. From the simulation, it was predicted that irrespective of the orientation of Ni crystal with respect to shear forces, helium nanobubble has a detrimental effect on the mechanical properties of the single crystal Ni. In comparison to the size of helium nanobubble, the higher concentration of helium atoms in the nanobubble have a more detrimental effect on mechanical strength. The focus of nuclear scientists is to develop future generation nuclear reactors as well as to predict the safe lifecycle of existing nuclear structures, which are in use for a long period of time. Helium nanobubbles change the mechanical behavior of underlying nuclear material in a significant manner, results presented in this thesis will help in developing a better understanding about the deformation in irradiated Ni crystal. Tue, 01 Jun 2021 00:00:00 GMT http://localhost:8081/jspui/handle/123456789/20893 2021-06-01T00:00:00Z http://localhost:8081/jspui/handle/123456789/20892 Title: Some Investigations to Improve the Performance in Rapid Investment Casting Process Authors: Naung, Ye Yint Abstract: The rapid prototyping technologies (RP) is very useful when a limited number of pieces are promptly required as: in making/ testing prototypes, design iterations, design optimizations. The fused deposition modeling (FDM) is one of the RP technologies that can use thermoplastic for making sacrificial patterns used in investment casting process, is used to produce parts with controlled dimensional tolerances. In the present research, study of the product prepared with FDM assisted IC process has been done and issues in procedure have been addressed & resolved. This study includes comparisons of (i) FDM pattern materials such as PLA & ABS, (ii) block mould casting & shell mould casting, (iii) wax pattern, wax coated polymer pattern and uncoated plastic pattern, have been done. This work also shows the feasibility of direct shell printing through 3D ceramic printing with extrusion and SLS based processes. FDM pattern based RIC is faster & economical. Shell mould casting gives better result than block mould casting. Ceramic shell making process can be improved by optimized ceramic composition, drying time, and proper orientation. A thin wax coating on plastic patterns can improve the dimensional accuracy and surface finish of the investment castings made by using FDM based patterns. By varying infill rate minimum density of FDM pattern can be employed with sufficient strength. Polymer pattern are more robust and strong than wax pattern so not damaged during operation & handling. Tue, 01 Jun 2021 00:00:00 GMT http://localhost:8081/jspui/handle/123456789/20892 2021-06-01T00:00:00Z