Papers by Keyword: Shear Angle

Abstract: Parallel turning is one among the advanced unconventional turning process. It employs two turning tools operating concurrently to cut the material from the workpiece. For turned rotary components, surface integrity is a major quality indicator that determines the fatigue life of the finished workpiece. Tool parting distance, rake angle and edge radius affects surface integrity. Part I dealt with numerical analyses to determine the effect of parting distance on surface integrity using finite element based commercial software Abaqus 6.14. Here in Part II, the impact of rake angle over surface integrity for various cutting speeds and feeds are numerically analyzed. It was observed that with the rise in negative rake angle the negative residual stresses decreased for the machined surface of leading and lagging cutting tool. When the rake angle is increased from-10 ̊ to-2 ̊, percentage reduction of negative residual stresses is same for the turned surfaces of both tools. The cutting velocity was 250 m/min and feed 0.2 mm/rev. With the rise in rake angle, the friction angle reduced but shear angle raised. When the cutting velocity increased, the shear angle of the leading and lagging cutting tool reduced. Lower shear angle causes higher stagnation region which further causes higher compressive surface residual stress.

Abstract: In this paper, we consider a detailed technological process for manufacturing parts, namely, a gear wheel. The proposed method with the intervention of modern 3D modelling makes it possible to improve the main indicators of quality and strength of parts. Based on the results obtained, a cycloid transcendental system of circular motion of a gear wheel with the specified basic parameters was modelled. Using multifunctional modules, we studied the vibrations of the gear wheel at different points in time. It was found that due to the fatigue and contact strength, it is possible to ensure uniform flexural strength of the gear teeth. And also, by adjusting the profile of the teeth of the part, we selected the desired strengthening coefficient. The presented dependence of the angles of inclination of the gear teeth on the transformation coefficient allows you to improve the main indicators of quality and strength by at least 2 %.

Abstract: Orthogonal-to-oblique transformation model, which is formulated based on the cutting database including shear stress, shear and friction angles, can be used to predict cutting forces in high speed milling process and any other machining process. The involved shear stress, shear and friction angles are traditionally identified from abundant number of turning experiments. For the purpose of saving experimental cost, this paper presents a novel method to identify these parameters directly from flat end milling processes. Identification procedures are established by transforming the cutting forces measured in Cartesian coordinate system into a local system. The advantage lies in that in spite of the cutter geometries and cutting conditions, only a few tests are required to develop the model, which is experimentally validated to be effective for predicting the cutting force in terms of magnitude and shape in other machining cases.

Abstract: This paper describes an experimental study on the pure shear properties of E-Glass woven fabric by picture frame test. During shear deformation, the fabric yarns experience large angular change between warp and weft yarns. The picture frame test is one of the fundamental methods to characterize the in-plane shear behaviour of woven fabrics and can produce a quite uniform shear deformation state in the fabric sheet. Tests are conducted on two different size of EGlass specimens 40x40 mm and 80x80 mm. For a double increase the specimen size, the values of shear force and axial load are also almost double increase at the maximum displacement and shear angle.

Abstract: Shear angle and friction angle are the two characteristic parameters in orthogonal cutting model. This paper investigated effects of feed per tooth on shear angle and friction angle in orthogonal milling of titanium alloy Ti6Al4V by experimental approach. Three different straight tooth milling tool with different rake angles are used in this research. Experimental results reveals that in orthogonal milling of Ti6Al4V alloy, shear angle will decrease with increase of feed per tooth and friction angle will increase with increase of feed per tooth. And then variation of shear angle and friction angle affect the values of force coefficients. The experimental results provide deep understand of basic physical phenomenon in milling process and sheds light on more accurate cutting force modeling.

Abstract: Shear angle is a key parameter to characterize the metal cutting. In this paper the Merchant analysis model of shear angle is improved. The impact of shear angle on the shear stress is quantitatively analyzed by using of the unequal division shear zone model and Johnson-Cook constitutive model, and the functional relationship between the tool-chip friction angle and the shear angle is established by Schulz empirical formula. Thus the new shear angle calculation model is established. Calculation results and experiments verify the effectiveness of the improved Merchant model.

Abstract: shaped weaving is a method which using unequal length of the warp and weft to weave shaped fabrics on the ordinary weaving frames. After multi-layer wound and resin solidified, these shaped fabrics can be formed into whole three-dimensional preform parts, such as oval-shaped pressure vessels, conical tube, ring, etc. because the batch roller on frame is cone frustum, not cylinder, which makes the shear deformation happens when tuck-in fabrics. In this paper, through the establishment of shear deformation model of the annular shaped woven fabric, and theoretical derivation on shear deformation, then calculate the weft deformation angle by theoretical formula. By contrast, we found the calculated shear deformation angle is very near to that measured on the shape fabrics. This proves the shear deformation model and theoretical derivation are correct, accord with the real situation of the shear deformation. Key words: shape woven fabric, shear deformation, theory model,shear angle

Abstract: The discrete element method (DEM) has been recognized as an effective tool to simulate soil–tool interactions. In this study, a saturated sand cutting model is developed using a commercial DEM software, Particle Flow Code in Two Dimension (PFC 2D). In the model, soil are defined as particles with the basic PFC 2D model, full coupling with a deformable fluid. The mechanical interactions between particles and also between particles and the walls are modeled by sprints, dash-pots and friction sliders. The properties of the material and interactions (Poisson’s ratio, shear modulus and density, coefficients of restitution, rolling and static friction) relate to the particle properties and not to the bulk properties. Such quantitative and qualitative models are essential for improving the design, selection and use of water saturated sand cutting implements, in different field sand under different conditions. This paper describes a numerical experimental investigation of the failure characteristics of two-dimensional water saturated sand cutting. Comprehensive simulated tests were carried out on sandy loam using a box apparatus and two model plane blades of rake angles 30º, 60º and two angles of friction 32º,42º, respectively. Besides, there are two extreme densities of the sand, compacted and loose. These factors should provide a basis for the reliable prediction of the failure type.

Abstract: This paper briefly introduces and analyzes the basic working principle of the hydraulic shears of medium plate milling. This design can meet the optimum requirements of the hydraulic control system, such as the shear synchronization control and the distribution of shearing force.

Abstract: The forces involved in a cutting process are related, for example, with the power consumption, with the final quality of the workpiece and with the chip geometry obtained, since these forces determine the compression experimented by the chip and therefore its final geometry. The orthogonal cutting process assisted with a High Speed Filmation (HSF) permit obtains a digital filmation of the process with high magnification. This filmation permits to obtain a measurement of the longitudinal changes produced in the chip. This deforms are related with the Shrinkage Factor, ζ. And in this case the Stabler hypothesis is enabled, by that using the shear angle and the rake angle is possible obtain a value of the Shrinkage Factor in a different conditions.