Equity in distribution of benefits from water harvesting and groundwater recharge: an economic study in Sujala Watershed Project in Karnataka

The paper looks at the impact of water harvesting programs in ground water recharge through the case of the Sujala watershed in Karnataka. On comparison with areas of non sujala watershed and non watershed cases in one normal rainfall and one drought year, it was revealed that Sujala has been successful in recharging groundwater, improving farmers’ incomes and increasing crop production. Further the program is inclusive and the benefits were accrued even to the small and marginal farmers. In fact the net return for small and marginal farmers was higher that that for large and medium farmers. The study concluded that there is potential for expansion of Sujala pattern of watershed development program in other parts of Karnataka and India.Length: pp.720-746Water harvestingGroundwater rechargeWatershedsDevelopment projectsGroundwater irrigationWellsEconomic impact

Discrete quaternion Fourier transform in signal processing systems.

We define n th root of unity in quaternion space and then we define discrete quaternion Fourier transform. We use first order quaternion filter for implementing fourth order real co-efficient filter

Key-lock pair mechanism for access control using tribes of Farey fractions.

We propose a new single key-lock mechanism based on the concept of an access control matrix. In this system, each file is given a lock and each user is given a key and through simple operations on keys and locks the user access privilege can be revealed. We use Chinese Remainder theorem and tribes of Farey fractions in this method instead of the method based on Euler’s Theorem of Number Theory used by Chang [2]. An advantage of our method is the ease with which coding can be done for the locking mechanism and for the much larger number of users and files

A global–local approach for progressive damage analysis of fiber-reinforced composite laminates

The present work applies the global–local technique to the progressive damage analysis of fiber-reinforced composite laminates. A one-way, loosely-coupled global–local approach is developed as a combination of a low-fidelity linear global analysis and a high-fidelity local nonlinear analysis of specific regions within the structure, where damage is expected to occur. The local model is based on higher-order structural theories derived using the Carrera Unified Formulation (CUF), and specifically, Lagrange polynomials are used to model each ply through its thickness, leading to a layer-wise model. Composite damage is described using the CODAM2 material model, which is based on continuum damage mechanics. Initial assessments compare the relative performance of 3D finite elements (FE), 1D-CUF, and the proposed global–local approach via the freeedge stress analysis of a stiffened composite plate. The proposed technique is then used to predict the tensile strength of an open-hole specimen. The last assessment simulates damage progression within an over-height compact tension specimen using the global–local approach. Verification and validation of results are carried out via refined models and experiments from literature. The results demonstrate the accurate evaluation of 3D stress fields and composite laminates’ mechanical response in the progressive damage regime. A multi-fold improvement in the computational cost is shown when compared to full-scale CUF analyses and indicates this technique’s strong potential towards the computationally-efficient high-fidelity analysis of complex and large-scale composite structures

Progressive damage analysis of composite laminates subjected to low-velocity impact using 2D layer-wise structural models

The present work deals with the progressive damage analysis of composite laminates subjected to low-velocity impact. We develop a numerical model using higher-order structural theories based on the Carrera Unified Formulation (CUF) with Lagrange polynomials and resulting in a 2D refined layer-wise model. To model damage, we use a combination of the continuum damage-based CODAM2 intralaminar damage model to account for fibre and matrix damage within the ply, and cohesive elements to account for delamination between successive composite plies. We carry out numerical assessments for the case of a linear elastic composite plate subjected to impact, to compare the current framework with standard approaches based on 3D finite element (FE) analysis. We, then, consider the elastoplastic analysis of a bimetallic laminated plate to compare the performance of the proposed layer-wise model and 3D-FE approaches, for the case of nonlinear impact analysis. The final assessment considers progressive damage due to low-velocity impact, and the results are compared with available literature data. The numerical predictions show a good correlation with reference experimental and simulation results, thus validating the current framework for impact analysis of composite structures. Comparisons of the proposed layer-wise structural models with those based on 3D finite elements demonstrate the improved computational efficiency of the CUF models in terms of model size and analysis time

A global–local approach to the high-fidelity impact analysis of composite structures based on node-dependent kinematics

The objective of the present work is to investigate progressive damage in fibre-reinforced composites under varying load conditions, and in particular transverse impact loads, using a global–local approach. The numerical models are built using higher-order structural theories based on the Carrera Unified Formulation (CUF). The Node-Dependent Kinematics (NDK) technique, an intrinsic feature of CUF models, is employed which enables the selective refinement of critical regions of interest within the structure and results in a global–local analysis. Progressive damage is governed by the CODAM2 material model, which is based on continuum damage mechanics. A series of numerical assessments are performed on composite laminates under varying load conditions, and predicted results of the global–local analysis are found to be in good agreement with experimental data, thereby validating the proposed approach. A comparison of its performance with reference high-fidelity CUF models of the full structure demonstrates the computational efficiency that can be achieved using the CUF-NDK global–local approach

Global/local capabilities of MUL2 for the nonlinear analysis of composite structures

MUL2 is an in-house finite element (FE) platform whose structural formulation is based on the Carrera Unified Formulation (CUF). This work presents some of the latest capabilities of CUF and MUL2 concerning the structural analysis of complex composite structures. The modelling exploits global/local techniques and the node-dependent-kinematics (NDK) recently proposed within CUF. Assessments consider the evaluation of failure indexes along free edges, the tensile strength of notched specimens, and failure progression. Performances are evaluated in terms of accuracy and computational costs, and perspectives on advanced NDK modelling are drawn

Evaluation of the influence of voids on 3D representative volume elements of fiber-reinforced polymer composites using CUF micromechanics

This paper presents numerical results on the micromechanical linear analysis of representative volume elements (RVE) containing voids. The modeling approach is the micromechanical framework within the Carrera Unified Formulation in which fibers and matrix are 1D finite elements (FE) with enriched kinematics and component-wise capabilities. RVE models are 3D and consider all six stress components. Such a modeling strategy leads to a twofold reduction of the degrees of freedom as compared to 3D FE. The numerical assessments address the influence of the volume fraction and distribution of voids, including comparisons with data from the literature and statistical studies regarding homogenized properties and stress fields. The proposed modeling approach can capture the local effects due to the presence of voids, and, given its computational efficiency, the present framework is promising for nonlinear analysis, such as progressive failure