Showing papers by "J. N. Reddy published in 2023"
TL;DR: In this paper , a pseudo-inverse-based static finite-element solver was developed to model the elastic deformation and non-local brittle fracture of solids, which is faster than using the traditional approach based on the singular value decomposition method.
3 citations
TL;DR: In this article , a closed-form solution of the Reddy beam theory is developed and applied to investigate the bending behavior of straight and curved functionally graded (FG) beams, where the material properties change continuously from one surface to another in the thickness (or height) direction.
TL;DR: In this paper , the effect of FGMs on the reduction of stress-shielding imposed on a bone was studied parametrically by conducting simulations of various two-dimensional and three-dimensional computational models.
TL;DR: In this article , the generalized stress/strain and corresponding local quantities obtained from three classical beam models commonly used in the literature are compared, namely, the Euler-Bernoulli, Timoshenko, and Reddy beam models.
Abstract: The purpose of this paper is to compare the generalized stress/strain and corresponding local quantities obtained from three classical beam models commonly used in the literature: the Euler–Bernoulli, Timoshenko (or first-order shear deformation), and Reddy (or third-order shear deformation) beam models. In particular, we present an analytical solution for the equations governing the Reddy beam model, which is typically solved numerically. By expressing the solutions of all three models in terms of constants with the same physical meaning, we are able to make a direct comparison between them and identify the additional contributions of the higher-order models. We also compare the results with approximate solutions and find that while they provide satisfactory solutions for generalized displacement, they can lead to a significant underestimation of the stress field, with percentage errors that are greater than tolerable for practical purposes. This study provides new insights into the behavior of different beam models and their limitations in engineering applications.
TL;DR: In this paper , a 3D axisymmetric elasticity solution for pull-out stresses in anchored anchors with spatially stiffness-varying adhesive is presented, where a stiff rod embedded in a semi-infinite rigid half-space through an adhesive bondlayer, representing a general anchor problem is analyzed.
Abstract: Three-dimensional axisymmetric elasticity solutions for pull-out stresses in bonded anchors with spatially stiffness-varying adhesive are presented. A stiff rod embedded in a semi-infinite rigid half-space through an adhesive bondlayer, representing a general anchor problem is analyzed. The adhesive layer is considered to have a smoothly varying stiffness over embedded length. Two cases of particular engineering relevance are considered: (i) stiffness grading of the bondlayer to enhance performance while retaining the critical length characteristics of bonded anchors, and (ii) modulus reduction of the bondlayer representing adhesive degradation proximal to the loaded-end. Theoretical solutions are developed adopting a stress function approach in conjunction with a variational method that compare well with 3D axisymmetric finite element (FE) results. Both theoretical and FE results indicate that the maximum shear stress in the adhesive decreases over 60% for a graded bondlayer for the parameters considered here without warranting a longer embedment length. In contrast, the degraded bondlayer reduces shear stress peaks significantly but warrants a larger embedment length to enable shear-dominated stress-transfer, disadvantageously loading the embedded-end in tension. A design map showing the critical embedment length required for degraded bondlines as a function of fractional embedment length over which bondline is regarded to have degraded is presented. In addition, interfacial fracture behaviors of the tailored and degraded adhesive anchors were examined through FE analyses finding that the tailoring reduces the energy release rate and has the potential for enhancing damage tolerance. The findings of the study indicate that the stiffness-tailored and -degraded bondlayers significantly redistribute the stress field with concomitant influence on stress-transfer and interfacial debonding characteristics of bonded anchors.
TL;DR: In this paper , the authors investigated the strain and stress states in an aluminum single lap joint bonded with a functionally graded Al2O3 micro particle reinforced adhesive layer subjected to a uniform temperature field.
Abstract: This study investigates the strain and stress states in an aluminum single lap joint bonded with a functionally graded Al2O3 micro particle reinforced adhesive layer subjected to a uniform temperature field. Navier equations of elasticity theory were designated by considering the spatial derivatives of Lamé constants and the coefficient of thermal expansion for local material composition. The set of partial differential equations and mechanical boundary conditions for a two-dimensional model was reduced to a set of linear equations by means of the central finite difference approximation at each grid point of a discretized joint. The through-thickness Al2O3-adhesive composition was tailored by the functional grading concept, and the mechanical and thermal properties of local adhesive composition were predicted by Mori–Tanaka’s homogenization approach. The adherend–adhesive interfaces exhibited sharp discontinuous thermal stresses, whereas the discontinuous nature of thermal strains along bi-material interfaces can be moderated by the gradient power index, which controls the through-thickness variation of particle amount in the local adhesive composition. The free edges of the adhesive layer were also critical due to the occurrence of high normal and shear strains and stresses. The gradient power index can influence the distribution and levels of strain and stress components only for a sufficiently high volume fraction of particles. The grading direction of particles in the adhesive layer was not influential because the temperature field is uniform; namely, it can only upturn the low and high strain and stress regions so that the neat adhesive–adherend interface and the particle-rich adhesive–adherend interface can be relocated.