Applied Mechanics and Materials Vol. 607

Abstract: High speed Schlieren imaging, pressure tapping points and optical emission spectroscopy for temperature and heat flux data are essential measurement techniques for analysis of bow shock dispersion, aerodynamic performance or heat transfer of spacecraft in atmospheric re-entry. However, design and manufacturing of a high voltage pulsed-plasma jet for testing in a supersonic counterflow deserves careful examination. High voltage electrification combined with high temperature sparking between electrodes possesses several design difficulties and manufacturing challenges which need to be addressed that form the basis of the design principals and manufacturing methodology of an Apollo capsule pulsed-plasma jet for successful testing and experimentation of the model.

Abstract: The basic hypothesis of this article focuses on the changes in the plastic deformation under the machined surface during drilling. For experiments applied a new Cast Iron GTW 35-04, Stainless steels DIN 1.4301 and ISO C45 carbon steel. The problem of drilling holes with diameter D=2 to 15 mm resides in the fact that 20 to 30% of these holes do not comply with prescribed requested requirements. This article presents the results of experiments focusing on the study of the damage process in helical drills with diameter d=6.0 mm. This study also includes an analysis of accompanying phenomena in the cutting zone by measuring some selected parameters.

Abstract: The The basic hypothesis of this article focuses on the study of accompanying phenomenas in the cutting zone of the stainless steels, with regard to the elimination of occurrence of poor-quality holes when drilling into new austenitic ELC (Extra Low Carbon) stainless steels. The problem of drilling holes with diameter D=1 to 9 mm resides in the fact that 20 to 28 % of these holes do not comply with prescribed requested requirements. The result of the deformation is very often the unforeseen destruction of the cutting tools; therefore their operational tool life is reduced. This article presents the results of experiments focusing on the study of the plastic deformation of the chips, at drilling with diameter d=5 mm when drilling into a new austenitic ELC stainless steels. This study also includes an analysis of accompanying phenomena in the cutting zone by measuring some selected parameters. The results of the experiments were compared with Cr18Ni8 steel and then verified when drilling holes into specific products.

Abstract: In petroleum industry, drilling is one of the most important aspects due to its economics. Reduction in drilling time is desired to minimize operations cost. This work focus on Polycrystalline Diamond Compact (PDC) drill bit which is categorized as a fixed cutter drilling bit. Problem such as wear and tear of PDC cutter are some of the main factors in drilling process failure affecting the rate of penetration (RoP). Thus, an intensive study in drill bit design could potentially save costs if the drill bit efficiency can be improved. The objective of this research is to improve the PDC cutter design and analyse design improvement in relation to the rate of penetration using reverse engineering (RE) approach. RE method is capable of resolving unavailable drill bit blueprint from the manufacturer due to propriety and confidential. RE non-contact data acquisition device, 3D laser scanner will be used to obtain cloud data of the existing worn drill bit. Computer Aided Design (CAD) software is used to convert cloud data of the PDC drill bit into 3D CAD model. Optimization of PDC Drill bit is focused on feature design such as back rake angle, side rake angle and number of cutters. CAE software is used to analyse the effect of the design feature modification to rate of penetration. Results show rate of penetration increases as the angle of both rake angle and number of cutter decreases.

Abstract: On the basis of ANSYS/LS-DYNA, the finite element model of incremented forming of conical part was constructed. The plastic deformation area of blank was increased and crack was delayed in multistage. Forming parts with the angle of 90°use multistage forming. Focused on the investigation of the influence of process parameters on the thinning rate and the thickness distribution then least-square response surface method was adopted to set up the approximate optimization model for thinning. The optimization on the approximate model was carried out using sequential quadratic programming method. The results show that the experimentally thinning rate is consistent with the theoretic result based on the homogeneous thickness distribution.

Abstract: Continuous-type electric furnace for thermal treatment to recover metal values from waste mixed batteries was newly developed to enhance it with safe, efficient, and eco-friendly processes. Waste mixed batteries were charged continuously into the reactor and handled in the furnace at 500°C for 2 hours under argon atmosphere and they were found to be separated in side reactor with easy. The electrodic powder including valuable metals such as Mn, Ni, Co, Zn, etc. was recovered from bulk components through sieving process.

Abstract: Machine tool chatter is a type of intensive self-excited vibration of the individual components in a machine-tool-fixture-work system. Chatter affects the cutting process and may lead to negative effects concerning surface quality, cutting tool life, and machining precision. However, modern manufacturing industries and their end users demand fine surface finish, high dimensional accuracy as well as low operation costs which include the cost of tooling. Therefore, any effective damping technique, which reduces or eliminates chatter, will significantly improve tool life and will be a profitable technique to implement in the industry. This paper presents a novel chatter control method in turning of (AISI 304) stainless steel by using permanent magnets. The study compared tool wear under two different cutting conditions: normal turning and turning with magnetic damping. A specail fixture made of mild steel was designed and fabricated in order to attach a powerful neodymium permanent magnet (4500 Gauss) to the carraige of a Harrison M390 engine lathe. The arrangement ensured that the magnet was placed exactly below the tool shank. The main idea was that the magnet will provide effective damping by attracting the steel tool shank and restricting its vertical vibratory motion during cutting operations. A Kistler 50g accelerometer, placed at the bottom front end of the tool shank was used to sense vibration. The data was then collected using a Dewetron DAQ module and analyzed using Dewesoft (version 7) software in a powerful Dell workstation. Response surface methodology (RSM) in Design Expert software (version 6) was used to design the sequence of experiments needed based on three primary cutting parameters: cutting speed, feed, and depth of cut. The tool overhang was kept constant at 120 mm in order to facilitate the attachment of the magnet fixture. Analysis of the recorded vibration signals in the frequency domain indicated that significant reduction in the vibration amplitude, as much as 86%, was obtained with magnetic damping. Next tool wear was analysed and measured using a scanning electron microscope (SEM). It is found that tool wear is reduced considerably by a maximum of 87.8% with the magnetic damping method. Therefore, this new magnetic damping method can be very cost effective, in terms of vibration reduction and tool life extension, if applied to industrial turning operations of metals.

Abstract: The hypothesis of half sine wave of cable galloping in span is adopted. For the problem of flabelliform iced cover conductor galloping, this paper presents a flabelliform cable galloping model of three degree-of-freedom based on D’Alembert Principle which considers the velocity coupling between air force and the cable torsional vibration. For the typical parameters of overhead line, based on the flabelliform cable galloping model of three degree-of-freedom, used the software Matlab for numerical simulation. Explore the flabelliform cable galloping characteristic of the wire on the condition of the different wind speeds, different angle of attack and span. According to the horizontal and vertical amplitude changes, determined the critical condition of transmission line dancing, and compared with the measured results are closer, according with the galloping mechanism of Nigol. It’s proved this theory is feasible, which is helpful to further study and the character of galloping.

Abstract: Mixing homogeneity and the feedstock rheological characteristic for optimal binder formulation in metal injection moulding is evaluated between Polypropylene (PP) and Sewage fat (SF) or Fat Oil Grease (FOG). Difference powder loading of SS316L also being used here to determine the possibility of the best binder formulation selected could be optimised for optimal powder loading base on rheological characteristic analysis. Two binder formulations of PP to SF being selected here are 60/40 and 70/30 accordingly with the powder loading of 60% and 55% for each binder formulation. The analysis will be base on viscosity, shear rate, temperature, activation energy, flow behaviour index and moldability index. It is found that rheological result shows all the two binder formulations with both powder loading exhibit pseudoplastic behaviour or shear thinning where the viscosity decrease with increasing shear rate. Feedstock viscosity also decrease with increasing temperature indication of suitability for moulding. Results from all the analysis conducted shows that the volumetric powder loading of 60% with binder volumetric of 60% for PP and 40% for SF contributes significant stability and suitability for optimum powder loading.

Abstract: In this paper, the relationship between the shrinkage of the thin-walled wax part in the investment casting process (ICP) and the process parameters including mold temperature, melt temperature, packing pressure and holding time are investigated through a series of experiments. The relationship is successfully described by a mathematical regression model which is based on the response surface methodology (RSM). The rationality and adequacy of the mathematical model are checked via analysis of variation (ANOVA) and a sensitivity analysis for process parameters on the dimensional shrinkage variation are conducted which shows that the contribution percentages of mold temperature, melt temperature, packing pressure and holding time are 23.77%, 43.67%, 11.85% and 16.99%, respectively. Additionally, the optimal setting of the process parameters is also obtained by calculating the desirability function. The optimal combination of the mold temperature, melt temperature, packing pressure, and holding time is 74°C, 30°C 25bar, and 5 sec, respectively.