The aim of the study is to observe the strength increment of concrete by using fly ash as a partial replacement of fine aggregate. For that, three mix ratios – 1:1.25:2.5, 1:1.5:3 and 1:2:3 (weight-based) have been considered. For each ratio, fly ash was used as 0%, 10%, 20% and 30% of the fine aggregate. The curing period and the water-cement ratio (W/C) were 28 days and 0.5, respectively. It was revealed that the compressive strength of the concrete was increased with the addition of fly ash. And it was the maximum at 10% of fly ash content. A nonlinear relationship has been proposed where compressive strength has been used as the function of the weight of cement, fine aggregate, coarse aggregate and fly ash.

It is known that during the simulation of the adhesive contact problems highly nonlinear responses of interaction forces occur within the very narrow adhesive zone.It leads to the loss of quadratic-rate of convergence during Newton-Raphson iterations and unstable computational behaviour.In case of standard finite element formulation, a very fine mesh resolution is needed for the stable computations, but a significant computational cost is associated.For minimising the cost without the loss of accuracy of the solution, contact surface enrichment approaches have been presented.These approaches utilise the higher-order Lagrangian polynomial functions for the enrichment of contact finite elements.In the present work, based on the incorporation of fifth-and seventh-order Hermite interpolation functions two new enriched contact finite elements are formulated.The performance of proposed enriched contact finite elements is demonstrated through the simulation of peeling of an initially flat deformable strip from a rigid substrate.A stable solution is obtained at a relatively coarser mesh than the fully Lagrangian discretised finite element mesh.It is shown that the proposed higher order Hermite enriched contact finite elements attain better performance when compared with earlier introduced enriched elements.

This paper presents a promising numerical scheme for simulation of many harmonics in wave propagation.The wavelet-based adaptive technique eliminates the requirement for a very large number of nodes in finite element method for propagation of such waves.This dynamic adaptive grid selection is based on the fact that very few wavelet coefficients are required to represent a short pulse containing higher harmonics.The method is particularly useful where higher harmonics are ignored due to very high computational cost.In this work, B-spline and Daubechies wavelets-based non-standard (NS) multi-scale operator are applied, and the results are compared with the finite element method.

Inconel 625, having wide industrial applications, exhibits poor machinability because of rapid work hardening and poor thermal conductivity. Therefore, cutting fluids are utilised to remove heat and provide lubrication in the cutting zone, but their application poses serious environmental and health hazards, calling to minimise their use. Multi-walled carbon nanotube (NMQL) technique provides an effective alternative to flooded cooling-machining of Inconel and stainless steel. Current study evaluates performance of NMQL in terms of tool wear and surface finish during face milling of Inconel 625. To enhance thermal conductivity of MQL, soluble multiwalled carbon nanotubes (1% wt.) were mixed in vegetable oil. Cutting parameters were optimised to minimise tool wear and surface roughness and validation tests were also conducted under flooded and dry conditions to compare their performance with NMQL machining. Performance of cutting tool during NMQL machining was found to be 15.56% and 3.45% better than dry and flooded machining respectively, on the basis of tool wear (VB), and was 14.06% and 59.02% improved over flooded and dry machining respectively, in terms of surface roughness (Ra).

Nickel-based alloys are widely used in high temperature applications due to their favourable properties at extreme conditions. However, due to their high cost, efforts are being relentlessly made to extend the useful life of the components made from these alloys. Such life extension requires reliable constitutive models with detailed quantitative understanding of the factors contributing to property variations. Micromechanical analysis along with multi-scale methods can be a key enabler in developing the required high fidelity models. Particularly for properties such as creep that require long term prediction, accelerated tests with empirical models may prove insufficient. Thus, in the present work, a crystal plasticity-based creep model has been developed for solution strengthened nickel-based alloys. Through this model, the effect of microstructural variations in grain orientation, size, etc. on the secondary creep strain rate can be captured. The performance of the model is evaluated against creep data of alloy 617.

It is critical to handle geometric and material nonlinearities in a stable manner while solving the problems from solid mechanics, such that it results in a converged solution. The present work compares the suitability of generalised displacement control (GDC) and displacement control algorithms (DCA) by solving several 1D and 2D formulations. The ability of these algorithms to handle homogeneous and inhomogeneous deformations is also studied. A novel direct displacement control method (DDCM), coupled with Newton-Raphson method, is proposed and compared with GDC and DCA approaches. Appropriate conclusions are finally drawn based on the successful demonstrations of the numerical results obtained by GDC, DCA and DDCM approaches.

Burrs on cross hole on automobile brake master cylinder have an impact on service life and stability of the hydraulic braking system. Therefore, as for how to remove burrs on cross hole, this paper provides a flexible machining technology for deburring with the liquid impact-based fatigue fracture method. Firstly, a reasonable 3D model was established. Then Fluent software was used to conduct a numerical simulation analysis on inner flow passage of brake master cylinder in order to calculate the force condition of burrs surrounded by hydraulic oil. Next, modal analysis and harmonic response analysis on burrs were further conducted to calculate and analyse resonant frequency of burrs and verify feasibility of this method, which provides a reliable theoretical foundation for deburring methods for automobile brake master cylinder. In addition, machining technology of this method was optimised and a more reasonable machining plan was put forward, which was then applied on a machining platform and achieved great machining effect.

In order to provide theoretical basis for the design of large-scale prestressed rectangular aqueduct, saving engineering investment, and ensuring the safety and reliability of aqueduct structure. This paper adopts mixed discrete variable optimisation design method to carry out optimisation design for Sha river aqueduct of the south-to-north water diversion project, the objective function of optimisation design is project cost. Calculated results show that, optimisation design scheme of rectangular aqueduct is economic and reasonable, aqueduct structure meets the strength condition and stiffness condition, wind load has little effect for stress and deformation distribution of aqueduct, but water pressure has great effect for stress and deformation distribution of aqueduct. When stress concentration phenomenon at the junction of the longitudinal beams and transverse ribs in the rectangular aqueduct occurs, local stress is higher.

In the recent years, directionally solidified (DS) turbine blades are found widely in advanced aero-engines owing to their excellent creep resistance properties. Aluminising coating on turbine blades protects against high temperature oxidation and corrosion. Turbine blades of a military gas turbine engine are subjected to low cycle fatigue (LCF) damage during START and STOP cycles. The present investigation deals with the low cycle fatigue (LCF) life of a directionally solidified nickel-base super alloy MAR M 002. Influence of aluminising on LCF life of the DS alloy MAR M002 has been evaluated by carrying out strain controlled LCF test at 900°C with strain amplitudes (Δεt/2) of ±0.3%, ±0.5%, and ±0.8% at a strain ratio (R) of –1. At low strain, coating favours LCF life. Accumulated plastic strain and tensile stress developed during cyclic loading and stiffness ratio are being used to correlate fatigue life. Fractography revealed initiation of cracks in the coating and multiple secondary cracks.