Papers by Keyword: Thin Plate

Abstract: Aeroelasticity is a science to study interaction between aerodynamic, elastic and inertial forces. Flutter is the most dangerous aeroelasticity phenomena, that is defined as the dynamic instability of an object in an airstream. Following flutter phenomenon, unsteady aerodynamic forces generated from elastic deformations of structure. It can lead to a disastrous structural failure. This paper examined aeroelasticity properties of a flat copper alloy plate by combining simulation methods using ANSYS software and experimental methods with help of subsonic wind tunnel at M = 0.1. At the first stage, elastic properties of this thin plate were carried out by using vibrational experiments and modal method to determine the specific vibration frequencies. Then, these aeroelasticity properties were estimated at three different attack angles of 0^o, 5^o and 10^o. Finally, instability phenomenon of this flat plate was investigated within limited experimental conditions to be able to select objects and experimental solutions to be feasible and effective.

Abstract: Welding process is an efficient joining process of metals that is achieved by gas metal arc welding (GMAW) process. Localized heating during welding process can result in distortion of the welded plate. The estimation of magnitude and distribution of distortion are important to maintain the quality of products. Finite element method is implemented to investigate the distortions behavior of thin steel plate, cold rolled (SPCC) material in lap joint using GMAW process. A three-dimensional, two-step thermomechanical finite element model study was applied to analyze and evaluate distortion behavior in lap joint. The result of distortion from finite element analysis (FEA) was compared to experimental data to validate the accuracy of the method.

Abstract: This study describes the thermal diffusivity of thin duplex steel plates in the thickness direction measured using the laser-flash method after welding. The work reports the experimental efforts in recording temperature profiles of the grade UNS S32304 duplex steel during autogenous welding. The butt weld autogenous joints were carried out by the GTAW (gas tungsten arc welding) process with either argon or argon - 2% nitrogen atmospheres. The amount of nitrogen in the heat affected regions, after welding, was measured and correlated with the variation of the thermal diffusivity of the studied material. The temperature profiles were obtained using k-type thermocouples connected to a digital data acquisition system. Different thermal cycles and thermal diffusivity values were observed in the heat-affected zone (HAZ) for both samples. In the solidified zone (SZ) was observed similar increase of the thermal diffusivity values for the plates welded with pure argon and argon plus nitrogen atmosphere.

Abstract: We propose in this paper the development of a new rectangular finite element for thin plate bending based on the strain approach with linear elastic behavior. An analytical integration is used to evaluate the element stiffness matrix. The present element possesses the three main degrees of freedom (d.o.f) per node, namely, one transverse displacement (w) and two normal rotations about x and y axis respectively (Ɵ_x, Ɵ_y). The proposed displacement field represents exactly the rigid body motion and satisfies the compatibility equations. The numerical results converges rapidly to the Kirchhoff solution for thin plates, this makes the present element robust, better suitable for computations, and particularly interesting in modeling this type of structures.

Abstract: This article presents an experimental investigation of the friction stir spot welding process in thin-walled plates by using a special HSS tool. A review of the literature dealing with the analyzed problem was conducted and the experimental setup for FSSW experiments was described. The experiments were carried out on non-ferrous 5754 aluminum alloy, copper M2 and brass CuZn37. Variations of experimental axial force were obtained.

Abstract: The behavior of thin plate subjected to impact loading is still an interesting field to study. This paper studies about Aluminum thin plate perforation. It focused on the experimental result of thin plate perforation. The thin plates are tested using blunt and conical strikers on a instrumented impact testing machine. Two different thicknesses of was used to observed the maximum work done with four impact velocities. The result indicated that the maximum work done increased proportionally with impact velocities. In addition, an elastic FEM analysis is carried out to confirm the experimental result by using ANSYS software. Both experimental and numerical results showed a close agreement.

Abstract: Low solid fraction simple rheocasting using Al-25%Si is proposed to cast a product with thin fins. The characteristics of this casting are presented. A conventional die-cast machine was used. The low solid fraction semisolid slurry was made in the sleeve of the die cast machine. Super cooling was used to reduce the casting temperature. The huge latent heat of the Si was utilized because of its excellent flow ability. A model of a heat sink, which was 0.5mm thick, 25mm high with 0.5 mm draft angle, was could be cast by the proposed process.

Abstract: The present work developed a computer application for the finite element analysis of thin rectangular plates under uniformly distributed transverse load. The software, which was developed using Java programming language, is very user-friendly and flexible in the choice of the boundary conditions and mesh size. The choice of Java programming language was guided by its high memory management, which, in turn had a positive effect on the software runtime. The finite element analysis of a Kirchhoff isotropic plate under a uniformly distributed transverse load was carried out using the software. The results obtained agreed accurately with solutions available in literature. Error analysis conducted on the results confirmed that accuracy generally increases with an increase in the number of elements used in the discretization process. Specifically, for a 16 x 16 discretization, an accuracy ranging from 98.41 to 100 percent, and 95.83 to 100 percent was achieved for the five sets of boundary conditions handled, for deflections at the plate’s center and bending moments respectively.

Abstract: In the aerospace industry, numerous large parts with complex curvatures and several thin wall/web pockets are required to ensure stiffness and low weight for aircraft structures. Costly processes and dedicated setups are usually required to machine such thin plate components. Therefore, investigating new machining methods involving flexible setups for such parts is an interesting avenue for cost savings, but a big challenge as well, due to a lack of support and part flexibility. In fact, a flexible setup is a tooling system with several adjustable positioning supports, which can easily adapt to different workpiece geometries. In this paper, an experimental investigation of the machining of pockets for thin components using flexible setup is presented. A design of experiments is proposed to verify the ability of pocket machining for thin plates of aluminum 2024-T3 in terms of quality. During the machining tests, the cutting forces were measured using a Kistler dynamometer table, while the displacement of the plates, for the flexible setup configuration, was measured using a Keyence displacement sensor. The force and displacement signals were analyzed and a fine correlation proposed between them and the resulting quality of the part, expressed in terms of profile and size errors.

Abstract: A current challenge for researchers is the design and implementation of an effective vibration control method that reduces vibration transmission from vehicle structures such as aircraft. This challenge has arisen due to the modern trend of utilizing lightweight thin panels in aircraft structural design, which have the potential to contribute towards significant vibration in the structures. In order to reduce structural vibration, one of the common approaches is considering vibration neutralizer system attached to the structure. In this study, a vibration neutralizer is developed in a small scale size. The effectiveness of attached vibration neutralizers on a thin plate are investigated through experimental study. Prior to the experiment, a finite element analysis of Solidworks® and analytical modelling of Matlab® are produced in order to determine the structural dynamic response of the thin plate such as the natural frequency and mode shapes. The preliminary results of finite element analysis demonstrate that the first four natural frequency of clamped plate are 48Hz, 121Hz, 194Hz and 242Hz, and these results are in agreement with the plate’s analytical equations. However, there are slight discrepancies in the experiment result due to noise and error occurred during the set up. In the later stage, the experimental works of thin plate are performed with attached vibration neutralizer. Result shows that the attachment of vibration neutralizer produces better outcome, which is about 41% vibration reduction. It is expected that by adding more vibration neutralizer to the structure, the vibration attenuation of thin plate can be significant.