An Integrated Hybrid Methodology for Estimation of Absorptivity and Interface Temperature in Laser Transmission Welding

This study reports a new hybrid integrated technique to predict the absorptivity of absorber and the interface temperature of the joint in laser transmission welding. The new approach is more robust as the numerical model is confirmed through experimental observations initially with weld width and further with surface temperature. Experiments are performed on a polycarbonate sheets with electrolytic iron powder (EIP) as an absorber. The surface temperature and weld width are measured from the experiments. A transient 3-D finite element-based numerical model is developed for heat transfer analysis. The variation of heat flux with stand-off distance is also considered to enhance the accuracy of the computed results. The absorptivity is tuned in the numerical model so that the numerical weld width is in close conjunction with the experimental weld width. The numerical model is validated by comparing the upper surface temperatures at the center, measured in the experiments using infrared thermography. The results indicate that the surface temperatures in the numerical model are in good agreement with experimental observations, and the average error is less than 6%. The interface temperatures are estimated after the validation of the numerical model.

The Synthesis of Organic Oils Blended Magnetorheological Fluids with the Field-Dependent Material Characterization

Automation is one of the trending terminologies in the field of engineering to achieve various sensors and actuators such as the hydraulic system. Smart fluid is also one of the hot topics for researchers to develop a type of actuator in many control systems since the fluid’s rheological characteristics can be controlled or tuned by the intensity of the external stimuli. In this work, a new smart fluid of magnetorheological (MR) fluid is proposed and its field-dependent rheological characteristics are experimentally identified. An MR fluid using the carrier fluid as the blend of three different fluids, namely silicon oil, honey, and organic oil is prepared. In addition, two types of natural oils are used, sunflower oil and cottonseed oil. The samples are prepared using the blend as the carrier fluid, electrolytic iron powder coated with guar gum as the dispersed phase, and oleic acid as an additive. The quantity of oleic acid is optimized for 30% by weight of electrolytic iron powder. Two samples based on sunflower and cottonseed oil are synthesized and characterized for shear viscosity and shear stress with respect to shear rate subjected to a variable magnetic field. The blend-based MR fluid shows about 10% improvement over the sedimentation rate of silicon oil-based MR fluid as compared to that to conventional MR fluid. The cottonseed oil blend-based MR fluid performs better than sunflower-based fluid in terms of the viscosity and structure.

Development of a New Ecological Magnetic Abrasive Tool for Finishing Bio-Wire Material

This study proposes a new wire magnetic abrasive finishing (WMAF) process for finishing 316L SUS wire using ecological magnetic abrasive tools. 316L SUS wire is a biomaterial that is generally used in medical applications (e.g., coronary stent, orthodontics, and implantation). In medical applications of this material, a smooth surface is commonly required. Therefore, a new WMAF process using ecological magnetic abrasive tools was developed to improve the surface quality and physical properties of this biomaterial. In this study, the WMAF process of 316L SUS wire is separated into two finishing processes: (i) WMAF with ecological magnetic abrasive tools, and (ii) WMAF with industrial magnetic abrasive tools. The ecological magnetic abrasive tools consist of cuttlefish bone abrasives, olive oil, electrolytic iron powder, and diamond abrasive paste. The finishing characteristics of the two types of abrasive tools were also explored for different input parameters (i.e., vibrating magnetic field and rotating magnetic field). The results show that ecological magnetic abrasive tools can improve the initial surface roughness of 316L SUS wire from 0.23 µm to 0.06 µm. It can be concluded that ecological magnetic abrasive tools can replace industrial magnetic abrasive tools.

Synthesis and Characterization of Innovative Type Magneto-Rheological Fluid

This research work is concerned with synthesis of an innovative type of magneto-rheological fluid (MRFluid) using edible low-cost soya bean oil as a carrier liquid with three different concentrations of electrolytic iron powder as a suspended medium and additives as a commercial grease. The field-dependent rheological properties of MRFluid samples were tested under different magnetic field conditions using rheometer. The results of the field-dependent-rheological properties of the prepared MRFluid samples show good agreement with commercial MRFluid. This directly indicates that the proposed innovative type of MRFluid can be used in automotive suspension systems, dampers, vibration control devices and so forth. Sedimentation test is also carried out in order to know the stability of the MRFluids.