The aim of this work is to know more about the underprediction of springback in numerical simulation of sheet metal forming. There are a lot of factors which influence the accuracy of springback with numerical simulation.One factor responsible for the inaccurate springback prediction is the assumption of constant Young's modulus in FE analysis. Young's modulus, however, is found to decrease during plastic deformation. Therefore, an accurate model is needed to be implemented in FE analysis which can predict the decrease in Young's modulus. With passage of time, Young's modulus is found to...

Thermal effects play significant role in the design of a structure when it is supposed to work in hot environment. For this purpose a thorough analysis of structure is necessary that could precisely consider the effect of temperature change. At first an accurate thermal analysis is required that may be further followed by stress or dynamic analysis. In this work, shell finite element developed by Rolfes et al to perform 3D thermal analysis is studied using Ansys and results are found good when comparing with the 3D solid element result. The interlaminar shear stress analysis of...

Skin-stiffener structures are extensively used in the aerospace field due to their structural efficiency in terms of stiffness/weight and strength/weight ratios. The application of such panels is primarily within fuselages and wing boxes, where the weight saving potential of composite materials compared with aluminum alloys is well known. However, design of composite panels involves the optimization of a large number of variables such as ply thickness and plate widths. Further complication arises when the expert knowledge required for laminate design is considered and when the panel is...

Numerical simulations of sheet metal forming process based on finite element method (FEM) is widely applied for its powerful capability in forming process prediction. Since there are parameters which could affect the result of forming process, it becomes important to approach a set of parameters to improve the formability. In the present work, first, a comprehensive literature review was made for different optimization methodologies in sheet metal forming process. Then we proposed an optimization methodology using Response Surface methodology (RSM) and Genetic Algorithm (GA) for the...

Modal parameters of spacecraft structures are important indicators of their dynamic characteristics which can be used for vibration reduction and control. In the present research modal parameters of a rocket are identified by using continuous wavelet transformation. The advantages of the wavelet transformation for the modal parameters identification over other methods is study. Through finite element method transient dynamic response of a system is determined then continuous wavelet transformation is applied to find the modal parameters like modal frequency, mode shapes and damping ratio.

Composite stiffened panels have been used in aerospace industries for past decades. Due to light weight nature composite panels are prone to buckling. In this study buckling load for Ortho-grid panel and Iso-grid panel is determined. This was accomplished by developing a composite laminate for both skin and stiffener using MSC PATRAN/NASTRAN was used for linear buckling analysis of composite panels. The buckling loads of two panels were determined based on finite element analysis results, including geometric dimension, thickness of the skin, number of laminae, ply stacking sequence, thickness...