Applied Mechanics and Materials Vols. 217-219

Abstract: In this paper,Fracture Toughness of TC11 alloy material at normal temperature is found out by Finite Element Simulation and Moire Interferometry. The feasibility and veracity of Finite Element Simulation is shown by comparing numerical and experimental results.

Abstract: Roller skew in roller bearings can cause heat generation and reduce bearing life. Therefore, design to minimise its occurrence is essential in bearing development. This study investigated the roller skew of a double row tapered roller bearing under various running conditions. A new system of measurement using two differential variable reluctance transducers (DVRT) was developed. It is evident that the roller skew of the double row tapered roller bearing can be measured. The shaft rotational speed has a significant effect on roller skew but the radial load has little effect.

Abstract: A new formulation of triangle element is developed. Based on the concept of unsymmetric finite element formulation, classical linear triangle shape functions are used as test functions, and FE-LSPIM TRI3 element shape functions are used as trial functions. The former is fulfill the requirements of intra-element and inter-element continuity in displacement field, and the latter is a good alternative for requirements of completeness in displacement field. Typical test problems for static solids are analyzed. The results show that the proposed element has good accuracy, and is superior to classical linear triangle element and isoparametric quad element.

Abstract: The surface of PC beam has been covered with cracks and flaws, it causes deficiencies to the safety of system. The inspection system includes inspection equipment and data off-line management. First discuss the theory of data acquisition. Then discuss the data off-line management, which include denoising, enhancement and segmentation. The denoising is based on anisotropic diffusion, which can preserve edge region of higher gradient, and smooth region of lower gradient. The enhancement is according to the characteristics of NSCT different domain, different operators are used in different subbands. The crack segmentation is based on Otsu method, which is according the convexity and concavity of histogram of detected image. The result shows that they can get good performance.

Abstract: In order to predict the mechanical property during the actual production of gray cast iron, to qualify the casting for the requirement of mechanical property and to control the cost, in this paper a series of anatomy and mechanical property experiments are conducted based on the automobile engine cylinder head processed through the actual production. The actual Brinell Hardness (HB) and the pouring parameters of the cast iron are acquired through the experiment. According to the pouring parameters, the cooling curve is obtained through the Inte CAST software simulation and the cooling rate is also calculated. Based on the existing property prediction model, the Brinell Hardness property prediction model of the engine cylinder head is deduced. The prediction results conform well to the actual data results.

Abstract: This paper experimentally and analytically investigates the fatigue strength and of mechanical damage of the processed shafts. First, we carry out rotary bending fatigue tests and investigate the fatigue strength for smooth specimens, specimen made only using cutting work, and specimens processed using a new plastic working developed originally. Secondly, we measure the Vickers hardness values to investigate strain hardening near the processed part. Finally, we simulate stress and strain distributions of the shaft during the processing using finite element method (FEM) and calculate the stress concentration rate at the notch root of the processed part. Based on the processing experiments and the finite element analyses (FEA), we clarify that the plastic work mechanically does not reduce the fatigue strength of shafts in the processing range.

Abstract: Elementary indentation processes are relatively simple compression processes and they are quite extended in many fields of the industry. Nevertheless, the concatenation of these processes is a new approach and has interest from a technological point of view. In this work the geometry of multiple indentation processes is analyzed on flat surfaces. The state of the formed surface by several types of tools is studied and a model has been developed in order to quantify by means of shape parameters the quality of the theoretical surface depending on the technological and geometrical characteristics of the process.

Abstract: Mechanical alloying(MA) and field activated and pressure assisted synthesis(FAPAS) combining the method of in-situ synthesis were used for the preparing ultra-hard, super-abrasive AlMgB₁₄ metallic ceramic. AlMgB₁₄ was performed at 1500°C under a pressure of 60 MPa from the elemental constituents (aluminium, magnesium and boron (vacuum annealed 1500°C)). The sample was examined by SEM, EDS and XRD. The products contained uniform AlMgB₁₄. The hardness of AlMgB₁₄ prepared under these conditions is 27.2-32.5GPa, the average density is 2.62g/cm³ and the fracture toughness is 3MPam1/2.These values are in correspond to the hardness of AlMgB₁₄ prepared by mechanical alloying/hot uniaxial pressing (28-35GPa). Analysis of the mechanisms of fracture,the fracture surface of AlMgB₁₄ sintered at 1500°C is of transgranularfracture. A new approach is brought forward by the mechanical alloying assisted FAPAS process (MA-FAPAS) to have synthesized AlMgB14 with fast heating-up, efficiency, energy saving and high yield.

Abstract: In the present paper constitutive equations for a nonlocal plasticity model are presented. Elasticity is considered to be governed by local forces so that only the dissipation processes are adopted as nonlocal. Differing from other proposed models in which the isotropic hardening/softening variables are considered as nonlocal, in the present paper the nonlocality is extended in order to include the kinematic hardening behaviour as well, so that both types of hardening (kinematic and isotropic) are considered as nonlocal. The present formulation satisfies a variational condition representing nonlocal maximum plastic dissipation. The proposed constitutive formulation of nonlocal plasticity is thus equipped with a sound variational basis.

Abstract: Constitutive relations are presented for a model of nonlocal viscoplasticity within a variationally consistent suitable setting. The appropriate elastic and dissipative potentials are introduced within a generalized standard material framework. A formulation of variationally consistent constitutive relations is accordingly presented for a model of nonlocal viscoplasticity. The evolutive equations are illustrated for the proposed model in a general form which is able to include different models of nonlocal viscoplasticity and different hardening rules.