Tool For Many Industrial Applications Research Articles

Application of Digital Image Correlation technique to Erichsen Cupping Test

Digital Image Correlation (DIC) technique is a powerful and useful tool in many industrial applications for both scientific and commercial purposes. It has been widely used for mechanical tests to understand the behaviour of material. In this study, 3D DIC technique was adopted to Erichsen Cupping Test (ECT) to measure the fracture cup height and demonstrate its benefits over traditional measurement techniques. Ck75 steel sheet with various material thickness was used in the experiments. The flat specimens were fixed in a closed die set-up and stretched along two directions until fracture. All the experiments were performed on a manually operated hydraulic press with a constant cross-head displacement and recorded with high resolution cameras. Finally, to determine the fractured cup heights, the accurate and satisfactory results were obtained through DIC measurements. The full-field thickness distribution and the maximum fracture forces were also determined.

Effect of surface modification of a rectangular vortex generator on heat transfer rate from a surface to fluid

Surface cooling is an essential tool in many industrial applications. Effective utilization of the wetted surface area is an important factor in the heat transfer enhancement. It may be done by optimizing the shape of the extended surfaces meant for increasing the thermal diffusion, or by improving the thermal interaction between the solid and the fluid. Creation of differential pressure using vortex generator may improve the way the thermal energy is exchanged. It may be obtained by reenergizing the boundary layer using the generated vortices. In the present work the effect of surface textures of the vortex generator on heat transfer and vortex dynamics are studied. The CFD results show that multiple and single texturing on the leading and the trailing faces of the vortex generator, respectively, can enhance the primary vortex downstream of the vortex generator. This in turn enhances the heat transfer by increasing the average Nusselt number and the skin friction coefficient of the plate. The surface temperature is also found to be reduced by the stretching of the vortex with a minimal pressure drop.

Acceleration waveform replication on six-degree-of-freedom redundant electro-hydraulic shaking tables using an inverse model controller with a modelling error

A redundant electro-hydraulic shaking table (REST) of six degrees-of-freedom (6 DOFs) with eight hydraulic actuators is an essential experimental tool in many industrial applications for real-time simulation of actual vibrations, such as structural vibration, earthquake simulation and fatigue testing. In order to obtain a high-fidelity acceleration waveform on the REST, a feed-forward inverse model (FFIM) controller with a modelling error compensator is proposed in this study. A recursive extended least-squares algorithm is employed to identify an acceleration closed-loop transfer function of the REST. A zero phase error compensation technology is employed to guarantee stability of the designed FFIM because the identified acceleration closed-loop transfer function is a typical non-minimum phase system and its direct inverse transfer function is unstable. The modelling error compensator is designed to compensate for the modelling error between the identified transfer function and the actual experimental REST, which deteriorates the acceleration waveform replication accuracy of the REST. A 6 DOF REST experimental system was used to verify the proposed controller. Experimental results demonstrated that the proposed controller gave satisfactory acceleration tracking performances on the REST.