Showing papers by "Satish V. Kailas published in 2014"
TL;DR: In this paper, the fatigue behavior of conventional FSSW and friction stir spot welding refilled by the friction forming process (FSSW-FFP) in aluminum 6061-T6 lap shear specimens was investigated based on the experimental observations.
39 citations
TL;DR: In this article, a 3D model of friction stir welding was developed in finite element (FE) commercial code ABAQUS/Explicit using the Coupled Eulerian-Lagrangian (CEL) formulation, the Johnson-Cook material law and Coulomb's law of friction.
31 citations
TL;DR: In this paper, the static shear strength and fatigue properties of refilled friction stir spot welded AA 6061-T6 joints were evaluated using the optical micrographs.
Abstract: This study was aimed at evaluating the static shear strength and fatigue properties of the newly developed refilled friction stir spot welded AA 6061-T6 joints. The keyhole, the process disadvantage of conventional friction stir spot welding, was refilled successfully, using an additional filler plate, with specially designed tools. Two different tool profiles, namely, convex and concave, were used for the refilling process. Sound and defect free joints were obtained by the refilling process. Joints refilled with convex tools showed better static shear strength than those with the concave ones. The variation of microhardness in different regions of the weld was analysed. Fatigue tests were conducted on the lap shear specimens at a stress ratio of R = 0·1. The optical micrographs of the welds after fatigue failure in both the conventional and refilled processes were examined to study the fatigue crack propagation and failure modes.
29 citations
TL;DR: In this paper, a novel spot welding process named walking friction stir spot welding (WFSSW) has been applied for AA 6061-T6 joints using a tool movement over a distance of 15mm.
22 citations
TL;DR: In this paper, the feasibility of deposition of copper on the mild steel using friction surfacing method was reported, where commercial mild steel was chosen as the substrate and commercial pure copper as the consumable rod.
15 citations
TL;DR: In this article, the authors investigated the plunge and dwell phase of FSSW using three-dimensional finite element (FE) modelling and developed a 3-D FE model in the commercial code ABAQUS/Explicit using the Coupled Eulerian-Lagrangian Formulation, the Johnson-Cook material law, and Coulomb's Law of friction.
15 citations
TL;DR: In this article, a three dimensional (3D) model is developed in finite element (FE) commercial code DEFORM 3D/Implicit to obtain the desired parameters for FSSW.
13 citations
TL;DR: In this article, frictionally constrained conditions are identified and the evolutions of stick-slip regions are investigated in detail, and detailed numerical analysis has also been performed in order to understand the energy dissipation and the damage mode involved in the surface or subsurface damage.
Abstract: A Frictionally constrained condition implies dependence of friction force on tangential displacement amplitude. The condition may occur due to chemical, physical, and/or mechanical interaction between the contacting surfaces. The condition, sometimes also referred to as the presliding condition or partial slip condition, is characterized under fretting. Under such conditions, various experimental studies indicate the existence of two distinguishable regions, that is, stick region and slip region. In the present study, frictionally constrained conditions are identified and the evolutions of stick-slip regions are investigated in detail. Investigations have been performed on self-mated stainless steel and chromium carbide coated surfaces mated against stainless steel, under both vacuum and ambient conditions. Contact conditions prevailing at the contact interface were identified based on the mechanical responses and were correlated with the surface damage observed. Surface degradation has been observed in the form of microcracks and material transfer. Detailed numerical analysis has also been performed in order to understand the energy dissipation and the damage mode involved in the surface or subsurface damage. It has been observed that under frictionally constrained conditions, the occurrence of annular slip features are mainly due to the junction growth, resulting from elastic-plastic deformation at the contact interface. Ratcheting has been observed as the governing damage mode under cyclic tangential loading condition.
6 citations
TL;DR: In this article, Cattaneo and Mindlin approach has been adapted to model partial slip condition and normalized strain energy release rate have been evaluated at the surface and in the subsurface region.
6 citations
TL;DR: In this paper, a first-of-a-kind fretting machine with the capabilities of simulating different fretting regimes under ambient and high vacuum (10-5mbar) conditions and, temperatures up to 873K was used to understand the mechanics and mechanisms involved under fretting conditions.
1 citations
01 Nov 2014
TL;DR: In this paper, the authors have shown that cutting oil emulsions made from coconut oil and natural additives have superior cutting properties and are completely ecofriendly, and concluded that products made using these conditions are possible and is a necessity for man to lead a sustainable life.
Abstract: For product sustainability “closing the cycle” is the first requirement. If the materials used in making the product is not replenished at the rate at which it is being extracted, the cycle is open and the product would not be sustainable. This includes the materials used in generating the energy used to make the product, the transportation, use and disposal. If the materials used in a product, that includes lubricants, is one that cannot be replenished, it has to be recycled for the product to be sustainable. The other basic condition for sustainability is the eco-friendliness of the product. It is argued that the present lubricants do not fall in this category. Using the example of cutting oil emulsions we have shown that it is possible to meet the conditions of sustainability in terms of both the material extraction-replenishment cycle and eco-toxicity. Cutting oil emulsions made from coconut oil and natural additives are shown to have superior cutting properties and are completely ecofriendly. It is concluded that products made using these conditions are possible and is a necessity for man to lead a sustainable life. Closing the cycle, with respect to the energy used in the cycle will make the product completely eco-friendly.