Papers by Keyword: Torque

Abstract: Ignition energy is an important key factor needed in modern life concept with regard to a high technology usage. Almost 90% of the world's energy needed is obtained from fossil fuels, where diesel fuel is one of them. Coconut oil is one of bio-diesel resources which is very potential to be developed and it has a potency to replace diesel fuel. It is, therefore research regarding the effect of diesel fuel and coconut oil mixture on engine torque and rate of fuel consumption at various RPM variations is needed to be done. The tested engine was done on a 1200 cc Isuzu Panther using a mixing ratio of diesel fuel (S) and coconut oil (MK), namely: (1). 100% S: 0% MK (pure diesel), (2). 95% S: 5% MK, (3). 90% S: 10% MK, and (4). 85% S: 15% MK. The research method was a quantitative testing method on a laboratory scale. Research finding shows that the engine torque at the 95: 5 and 100: 0 mixtures has almost the same value of almost all of engine rotations. At the 90: 10 and 85: 15 mixing ratio, the engine torque tends to be unstable significant. It can be concluded that the ideal and stable engine torques were found at the combustion of 100: 0 and 95: 5 fuel mixtures. The lowest fuel consumption rate occurred at the combustion of 100: 0 and 95: 5; while the highest fuel consumption were occurring on a mixture of 90:10 and 85:15.

Abstract: A technique for studying contact stresses in the connection of heat-exchange tubes with tube sheets using roller rolling is described. Formulas for the determination of contact stresses, taking into account the formation of local deformation of the tube due to force action of each roller and features of axial movement of the tool spindle are given. Calculation was based on the assumption of medium continuity, known relations between normal stresses and deformations, as well as experimental oscillograms of the process.

Abstract: In deep hole machining, drilling parameters for twist drills have an important impact on tool life and economic efficiency. In order to explore the influence of drilling parameters on twist drills, this paper established a drilling model for twist drill 45 steel, orthogonal experiments were designed. AdvantEdge FEM finite element software was used to simulate the drilling force, torque and drilling temperature. The drilling force, torque and drilling temperature were analyzed by using the finite element simulation value as the orthogonal experimental value. In order to ensure that the simulation results have certain reference value, the drilling experiment was carried out in order to ensure the simulation results have reference value. Finally, the optimal combination of drilling parameters was obtained.

Abstract: The formulation and solution of the problem of double-T section rolling in universal groove using the variational principle of minimum total power with aim to determine integral forming and energy-power parameters are presented. Geometrical model of the deformation zone and the kinematically admissible velocity field were constructed accurate within two unknowns: forward slip coefficient ν, flange spread (pulling-down) . The comparison of the calculated values with the experimental data obtained on a laboratory mill 200 confirmed that the variational principle of minimum total power has sufficient accuracy for analysis of double-T section rolling in universal groove. The mean statistical error of torque calculation is 12.3 % while load calculation is 18.7 %.

Abstract: The twisting of an erect round metal roller (beam, roll) has a place in many metallurgical processes. For example, in the rolls of a wide-band mill at rolling of metal slab, in the leading rolls of flattening machines, in the asymmetric three-roll machines at bending of metal sheet, and so on. Under the large external torques in an erect metal roll, the plastic deformations can occur, which lead to the large residual stresses after an unloading of round roll. These residual stresses can bend the axis of the roll or cause it to a collapse under the subsequent loads. To estimate the value of residual stresses, it is necessary to know the spring-back factor of roll at a twisting. In this article, we have obtained the spring-back factor of the erect roll under a twisting.

Abstract: Circular cylindrical shells, application of which is widely widespread in a space-rocket technique and aircraft building, often have cutouts on the surface on structural and technological terms. The feature of the stress-strain state, when a circular hole is introduced into the shell, is the appearance of stress concentration zones, in which stress can be increased in many times. The linear static analysis often used for determination of maximal stresses in such elements of constructions does not reflect character of stresses change with increasing of the external loading. The results of Finite-Elements nonlinear static analysis of the stresses concentration caused by the hole presence depending on the size of torsion moment increasing from zero to the maximal values are presented in this article. The parametric analysis for the wide range of shells lengths and hole radii is carried out, at which different combinations the dependences of stresses concentration factor (SCF) on the value of torsion moment on all range of loading are defined. It is shown that the stresses fields, unlike the linear model of deformation, transform in the loading process. SCF obtained by taking into account the geometrical nonlinearity of deformation depends not only on the geometrical parameters of the considered sample, but also on the level of loading. There are two types of behavior of SCF dependence on the loading level and on the structure parameters. The SCF increases continuously in the first half of loading range. In the second half in case of the small holes the monotonous growth proceeds to the maximal values, and for the large holes ‒ SCF can fall at load increasing, and sometimes has the repeated areas of intensive growth in the pre-ultimate state.

Abstract: The objective of this study was to identify the best torque of insertion and removal of mini-implants with a twin screw design (compact and self-drilling) into artificial bones with density and trabecular thickness, similar to anterior, middle and posterior regions of the jaws. Observation of the mini-implants surface using electron microscopy was performed before and after the tests. The torque values obtained during the insertion and removal was measured by digital torque wrench. The analyzed results led to the conclusion that the insertion and removal torques were larger with increase in bone density and cortical thickness. The design of the threads of the mini-implants influenced the insertion torque. Threads with smaller pitch increased the value of insertion torque. The anterior bone drilling installation reduces the insertion torque independent of bone density. Torque increased mainly by increasing the bone density and not necessarily with increased cortical thickness suggesting that the bone density of the trabecular bone must be considered in designing the installation of mini-implants.

Abstract: Aluminum ball joint is an advanced structure using to connect steering parts with the merits of simple and lighting. Usually extrusion strength and torque are the most important parameters to evaluate the ball joint properties. Generally, the ball sealed in the Aluminum housing by forming method which has an impact on the extrusion strength and torques. So how to control the forming and achieve the best properties is very important. In the paper, the relations between housing dimension and strength, torque are studied; the influence of forming on torque is researched. The rules in them are achieved.

Abstract: Terrestrial vertebrates can walk more elegant than any other man-made legged mechanical models, which yield unstable locomotion with low speed. They continuously have modified their body structure and living patterns for the survival. They still continue their development. Legs are basically a serial linkage of rigid bodies connected by joints and exactly correspond to the manipulator in robot. Structure of living creatures are copied and modeled with 12 links, 12 joints and body, from the mechanical engineering viewpoint. Iterative Newton-Euler method is applied to compute torques acting all joints, which are required to calculate the total consumed energy to complete one locomotion cycle. Mechanical energy efficiency of different variables or systems are evaluated and compared by specific resistance. Parameters, specifying structure and locomotion, are applied to the simulation and the optimal values which minimize energy expenditure in locomotion are derived.

Abstract: With the rapid development of industrial technology, people have put forward higher requirements on the precision of process and assemblage for the part of the machine. In the process of accessory, a finish machining for the hole parts are generally necessary. There is greater impact on the processing accuracy because of the influence from the measurement methods, tool wear, lathe itself and other factors. In this paper, a regional centroid algorithm is proposed based on the visual measurement technology and mechanics principle. Firstly, the image of the workpiece is collected by the camera. And then the workpiece image is processed by the image processing technology. Thus, the torque of each pixel on the workpiece image contour relative to the center can be calculated. Finally, the detection and judgment of the part size is realized by the torque. Experiments show that this method can achieve accurate on-line detection for the inner diameter of the hole parts.