Loading In Transverse Direction Research Articles

Microstructure and Anisotropy of the Mechanical Properties of 316L Stainless Steel Fabricated by Selective Laser Melting

Significant anisotropy in mechanical properties was observed in 316L stainless steel (SS) that was subjected to selective laser melting (SLM) to produce a hierarchical structure, composed of molten pool, columnar grains, and a cellular substructure. Such anisotropy was induced by the geometric relationship between the boundary of the molten pool and the tensile force. The in situ tensile test showed initial deformation rapidly occurred at the boundary of the molten pool, followed by strain localization, and a lower ductility was obtained when loaded in the longitudinal direction (perpendicular to the molten pool). By contrast, the deformation was significantly constrained because of the geometry of the boundary of the molten pool, and substantial deformation occurred in the cellular substructure during loading in transverse direction (parallel to the molten pool). Finally, the quantitative analysis revealed that the high-level strength was attributed to the high-density dislocations and the fine cellular substructure.

Equivalent Stiffness Methods for Free Vibration and Bending of Bimodular Composite Laminated Thick Curved Beam

In this research work an attempt has been made to analyzed the bending and free vibration behavior of bimodular composite material laminated thick curved beam based on first order shear deformation theory (FSDT). The effect of coupling parameter is more severe in bimodular laminated beam as compare to unimodular laminated beam. Therefore, equivalent stiffness methods (VS and RC) are used to incorporate the effect of all the coupling parameters. In the present analysis uniformly distributed load in transverse direction is considered. Hamilton’s principle is applied to elaborate governing equations from energy functional, and the equations are solved by analytical method. The position of neutral axis, transverse deflection, through the thickness strain distribution and frequencies for positive and negative side bending are presented for different bimodular composite material laminated curved beam. The results are presented for different stacking sequence and geometric parameter of the beam. The non-dimensional neutral surface location, positive and negative side bending deflections and positive and negative half cycle frequencies are having same magnitude for [00]4 or [00/900]s laminated curved beam of Material 1 (Aramid Rubber), and for Material 2 (Polyester Rubber) they are not same.

Experimental Verification of Concentrated Load Transverse Distribution in Shear

An ability of reinforced concrete slabs to distribute concentrated load in transverse direction is an important property for their verification. Several methods for the assessment of transverse distribution (effective width) were proposed but they were not incorporated in the current standards. This paper deals with an experimental analysis of the effective width for shear verification of slabs subjected to concentrated load. Shear resistance of the slab specimens subjected to concentrated load obtained from tests has been compared with resistance of the slab strips loaded by uniform shear. Based on this check, the effective width has been evaluated. Experimental results were also compared with results of models introduced in relevant standards.

On the calculation of plastic strain by simple method under non-associated flow rule

Abstract The non-associated flow rule (non-AFR), which has been proved with advantages in accurately predicting yield stress components and Lankford coefficients, has different definitions for yield function and plastic potential function. Currently, there are two typical approaches to determine the plastic strain for non-AFR, one is called simple method which still uses the equivalent plastic strain (EPS) to calculate the plastic strain tensor, while the other is called full method which adopts the plastic compliance factor. Many researchers prefer to adopt the simple method in calculating the plastic strain due to its higher computation efficiency and its acceptable accuracy like the full method for some materials. However, the limitation and application condition of the simple method are still ambiguous. In the present work, a restriction for calculating the parameters in plastic potential function for the simple method is clarified and the limitation of the simple method has also been investigated. It is found that if the relative error of the difference between the yield function value and that of plastic potential function is within ±5% and hardening exponent is in the range of 0.1–0.3, the maximum absolute value of the relative error of the stress predicted by the simple method can be controlled less than 1.6%. Besides, an effective approach is introduced to reduce the error of the stress predicted by these two methods, which can improve the applicability of the simple method for those materials with the relative error of the difference between the value of yield function and that of plastic potential function is less than 10%. In order to have deeper understanding about their applicability, the two methods are compared under uniaxial tension along different orientations for AA2090-T3 and AA2008-T4 with the fully implicit return-mapping scheme. Fracture simulations of AA2090-T3 have also been conducted by introducing different methods. The results show that during the loading in transverse direction, the difference of EPSs predicted by these two methods is very small for AA2008-T4, while for AA2090-T3, the EPS predicted by the simple method is almost twice of that calculated by the full method. This further indicates that the applicability of the simple method mainly depends on the characteristics of materials.

Analysis of stress concentration in isotropic and orthotropic plates with hole under uniformly distributed loading conditions

The Behaviour of Stress Concentration Factor in rectangular and circular plates of Isotropic (Magnesium alloy) and Orthotropic material (E-glass/Epoxy) under static loading in transverse direction (UDL) has been studied. Aim of this work was to analyse the effect of D/A (From 0.1 to 0.9) and D/t ratio (From 0 to 90) upon Stress Concentration Factor (SCF) for Isotropic and Orthotropic material under given boundary conditions. To solve this problem, Finite Element Method (i.e. FEM Software) ‘ANSYS’ was used. Element length of 2mm was adopted. For design, a quarter rectangular plate and a complete circular plate were considered. Orthotropic material of rectangular plate for given boundary conditions achieved more Stress Concentration Factor than Isotropic Material. In Orthotropic Material, circular plate, Stress concentration was observed less than Rectangular Plate, whereas in Isotropic circular plate, SCF is almost similar to rectangular plate. Material properties of Orthotropic material has vital role for this behaviour when compared with Isotropic material and Geometry of the plate was also a reason to get SCF for Rectangular plate.

Effective in-plane elastic properties of auxetic honeycombs with spatial irregularity

An analytical framework has been developed for predicting the equivalent in-plane elastic moduli (longitudinal and transverse Young’s modulus, shear modulus, Poisson’s ratios) of irregular auxetic honeycombs with spatially random variations in cell angles. Employing a bottom up multi-scale based approach, computationally efficient closed-form expressions have been derived in this article. This study also includes development of a highly generalized finite element code capable of accepting number of cells in two perpendicular directions, random structural geometry and material properties of irregular auxetic honeycomb and thereby obtaining five in-plane elastic moduli of the structure. The elastic moduli obtained for different degree of randomness following the analytical formulae have been compared with the results of direct finite element simulations and they are found to be in good agreement corroborating the validity and accuracy of the proposed approach. The transverse Young’s modulus, shear modulus and Poisson’s ratio for loading in transverse direction (effecting the auxetic property) have been found to be highly influenced by the structural irregularity in auxetic honeycombs.

Overview of Methods of Analysis of Beams on Elastic Foundation

In this paper, the response of a beam on elastic foundation under static and dynamic loads is studied. The foundation model is based on Winkler hypothesis. Various methods are described for treating the analysis of beams on elastic foundation subjected to point load in transverse direction. An example problem is solved using finite element package ANSYS.

Reference stress approach for predicting creep deformation of metal matrix composites

AbstractA sound, mechanics based approach, using the reference stress concept, has been provided to allow the effects of volume ratio, fibre aspect ratio, and fibre spacing on the creep behaviour of uniaxial metal matrix composites to be quickly assessed. It is shown that fibres are much more effective than particles in reducing creep deformations. In addition, volume ratio and fibre aspect ratio have a large effect on creep properties, while fibre spacing has a relatively small effect. The existence of cracks at the ends of fibres is shown to reduce seriously the effectiveness of the reinforcement. The creep properties for loading in transverse directions are much lower than for loading in longitudinal directions.MST/2059

Reference stress approach for predicting creep deformation of metal matrix composites

A sound, mechanics based approach, using the reference stress concept, has been provided to allow the effects of volume ratio, fibre aspect ratio, and fibre spacing on the creep behaviour of uniaxial metal matrix composites to be quickly assessed. It is shown that fibres are much more effective than particles in reducing creep deformations. In addition, volume ratio and fibre aspect ratio have a large effect on creep properties, while fibre spacing has a relatively small effect. The existence of cracks at the ends of fibres is shown to reduce seriously the effectiveness of the reinforcement. The creep properties for loading in transverse directions are much lower than for loading in longitudinal directions.MST/2059

Tension line fields in a simply supported blanket subjected to in-plane body forces

Recent renewed interest in tension field theory is due to the intended use of large plastic blankets as load-carrying substrate for solar power collection arrays. Such substrate are used on spacecraft that extend their solar panels on the transfer orbit from low-Earth orbit to geosynchronous orbit, and are consequently subjected to acceleration during apogee engine firing, with the inertia! force's component in the plane of the blanket leading to the formation of wrinkles. The present paper contains a fundamental study, with experiments, of the wrinkling patterns of a simply supported blanket of uniform thickness, pretensioned in longitudinal direction, and subject to uniform loading in transverse direction. Nomenclature T = pretension, N 7) = pretension of primary field, N T2 = pretension of secondary field, N W = uniformly distributed body force (load), N Wl = portion of W in primary field W2 = portion of W in secondary field g = 9.80665 m/s2 h —• blanket height, m hj = height of primary field at blanket center, m h 2 = height of secondary field at blanket center, m hp — height of primary field anywhere in blanket, m hs = height of secondary field anywhere in blanket, m / = blanket length, m q = body force (load) per unit length, N/m s = visible sag at blanket center, m s' = sag of centerline of secondary field, m a. = angle between x- and ^-direction ap — angle of top tension line in primary field as = angle of bottom tension line in secondary field 0 = inclination angle of blanket end bars p = blanket material density, kg/m3 a = tensile stress, Pa T = shear stress, Pa