Papers by Keyword: Normal Stress

Abstract: To predict material’s formability in the hydroforming processes, the plane stress assumption would be invalid. The instability perturbation approach proposed by Hu et al. [1] is extended with the through-thickness normal stress by combining Hill’48 and Hosford’s yield criteria. The influences of through-thickness normal stress on the predicted forming limit strains in the forms of traditional Forming Limit Diagram (FLD) and equivalent plastic strain (EPS) based FLD (epFLD) are investigated. The results show that forming limit curves (FLCs) in both forms of FLD enhance with increasing through-thickness normal stress under proportional and non-proportional loadings. This new model can be utilized to study the effects of fluid pressure on the formability of orthotropic thin sheets.

Abstract: The comparison of the numerical methods: the finite element method, the Galerkin Method, the difference method is considered for the study of the stability of the rods. The dependence of the solution of the stability problem on the parameters of the discretization of these numerical methods is studied. It is shown that the mathematical models are sufficiently accurate to analyze the stability of the rods of constant and variable sections.

Abstract: Towbars are the main component of the assembly connection between the vehicle and the trailer. With proper use, recommended by the towbars producer, and the correct calculation and design by the manufacturer in accordance with international law, they ensure road safety.The main role of the towbars is to maintain in maximum safety conditions, the link between towing vehicle and various aggregates, namely trailers.

Abstract: The effect of adhesives behavior on the normal stress distributions of single-lap adhesive joints is investigated using the three-dimensional finite element technique. Numerical examples are provided to show the influence on the normal stresses of the joints using adhesives of different characteristics which encompass the entire spectrum of elastic stiffness behaviour. finite element analysis solutions of the normal stress distributions in the adhesive layer have been obtained for four typical characteristics of adhesives. The results indicate that Young’s modulus and Poisson’s ratios of adhesives strongly affect the normal stress distributions of the joints.

Abstract: In order to describe the bending property of sandwich beam with wood skin and binderless bamboo chips core, the effect of construction parameters and material type on bending normal stress and moment was analyzed systematically. It is shown that maximum bending normal stress of sandwich construction is bigger than homogeneous single layer beam with same cross section if the skin has higher modulus than the core. The bending moment can be taken almost by skin layer if the core modulus is much smaller than skin materials and core thickness should also be smaller to special point than total cross section. As for wood-bamboo sandwich composite, the core resistance to bending moment should be considered. The results can provide basic theory for design optimization of sandwich construction.

Abstract: The The 3D modelling, compared to the 2D-symmetrical rotation (axial) modelling, is much more complex and one of the reasons for this, with a view to plastic anisotropy, is that 3D modelling adopts normal anisotropy while 2D modelling adopts symmetrical rotational anisotropy. When the finite element method is used for numerical solving, the number of nodes in the discretization network is much larger in the 3D modelling and even when using last generation PCs the processing time is much longer. For this reason, for expedite calculations, as those needed to establish, in a first approximation, the optimal parameters of a deep drawing process I analysed in this paper the possibility to use the 2D-symmetrical rotation (axial) modelling. In a first phase, we intend to create a representative set of deep drawing problems and then to solve them through numerical simulations using Ansys package, using both the 3D modelling, in cartesian coordinates, and the 2D-symmetrical rotation (axial) modelling, in cylindrical coordinates. Runnings shall be carried out for various refinement levels of discretization network in finite elements. The calculation times shall be compared for these two modellings and following the comparative analysis of the results we can deduce the errors entered in the 2D modelling. These errors shall be assessed by analysing and comparing the extreme unitary stresses as follows: normal stress by the Ox and Oy axes , in the 3D modelling, and in the 2D modelling by the Ox / Oy axis; shear stresses by the XZ and YZ planes, in the 3D modelling and in the 2D modelling by the XZ plane.

Abstract: The shear strength of rock joints is highly depended upon the failure mode of joint asperity. At lower normal stress slide-up of one asperity up over another mode, however at high normal stress the joint asperities are sheared off at the base. This research uses pressure measurement film to directly measure the contact normal stress between smooth joint surfaces. It demonstrates that the density of color impression is capable of capturing the normal stress distribution behavior. The contact normal stress distribution during shearing is changed. After shearing, the contact stress becomes large. This increase in contact normal stress is to fracture the joint wall material.

Abstract: Adhesively bonding is becoming a widespread candidate technique for joining light-weight structural components. This paper investigates normal stress distribution in a single-lap adhesive joint using finite element method. Five layers of solid elements were used across the adhesive for obtaining an accurate indication of the variation of normal stress. All the numerical results obtained from the finite element analysis show that the spatial distribution of normal stress are similar for different interfaces. It can also be seen from the results that the left hand region is subjected to very high stress.

Abstract: This paper deals with the stress discontinuities in normal stress distribution of adhesively bonded beams. The 3-D finite element analysis (FEA) software was used to model the beams and predict the normal stress distribution along the whole beam. The FEA results indicated that there are stress discontinuities existing in the normal stress distribution within adhesive layer and adherends at the lower interface and the upper interface of the boded section. The numerical values of the normal stress concentration at key locations of the beams and the stress concentration ratio are discussed.

Abstract: A Model of Chip Formation with a Single Conditional Shear Surface Cannot be Implemented in Determining the Stresses and Strains in the Blank and Chip neither Nor in Determining the Contact Stresses at the Working Sections of the Front and Read Cutter Surfaces. at the same Time, it has been Established Experimentally that the Cut Layer is Converted to Chip in a Plastic Zone of Complex Form. Numerous Attempts have been Made to Simulate this Zone by Constructing Slip-Line Fields. According to Plasticity Theory, Slip Lines Constitute Two Families of Mutually Orthogonal Curvilinear Coordinates, along which the Maximum Tangential Stress Acts. if the Kinematically Possible Slip-Line Field is Constructed, it is Possible to Calculate the Stress–strain State in the Chip-Formation Zone.