Strain Sensor’s Network for Low-Velocity Impact Location Estimation on Carbon Reinforced Fiber Plastic Structures: Part-I

In this work, we have investigated the strain response (angular/spatial) from fiber Bragg grating (FBG) sensor & resistance strain gauge (RSG) sensors bonded to the composite structure due to the projectile low velocity impact (LVI). The number of sensor & its orientating has been optimized based on such experimental data and designed an optimum sensor network for faithful LVI detection. In order to study the efficacy of the sensor network, an impact localization algorithm based on peak strain amplitude from the sensor bonded to the structure was used in this study. Further the detection efficiency of the algorithm has been improved using weighted average value around the peak amplitude of strain experienced by the sensor. We found that for the high energy (~35 J) LVI the maximum distance error (Euclidian distance) was 50 mm for 80% of total trail case. Furthermore, we have developed and compared the relative performance of the algorithm cited in the literature, will be presented in PART-II of the same Journal

Development of Cytoplasmic–Nuclear Male Sterility, Its Inheritance, and Potential Use in Hybrid Pigeonpea Breeding

Pigeonpea [Cajanus cajan (L.) Millsp.] is a unique food legume because of its partial (20–30%) outcrossing nature, which provides an opportunity to breed commercial hybrids. To achieve this, it is essential to have a stable male-sterility system. This paper reports the selection of a cytoplasmic–nuclear male-sterility (CMS) system derived from an interspecific cross between a wild relative of pigeonpea (Cajanus sericeus Benth. ex. Bak.) and a cultivar. This male-sterility source was used to breed agronomically superior CMS lines in early (ICPA 2068), medium (ICPA 2032), and late (ICPA 2030) maturity durations. Twentythree fertility restorers and 30 male-sterility maintainers were selected to develop genetically diverse hybrid combinations. Histological studies revealed that vacuolation of growing tetrads and persistence of tetrad wall were primary causes of the manifestation of male sterility. Genetic studies showed that 2 dominant genes, of which one had inhibitory gene action, controlled fertility restoration in the hybrids. The experimental hybrids such as TK 030003 and TK 030009 in early, ICPH 2307 and TK 030625 in medium, and TK 030861 and TK 030851 in late maturity groups exhibited 30–88% standard heterosis in multilocation trials

Strain Sensor’s Network for Low-Velocity Impact Location Estimation on Carbon Reinforced Fiber Plastic Structures: Part-I

116-124In this work, we have investigated the strain response (angular/spatial) from fiber Bragg grating (FBG) sensor & resistance strain gauge (RSG) sensors bonded to the composite structure due to the projectile low velocity impact (LVI). The number of sensor & its orientating has been optimized based on such experimental data and designed an optimum sensor network for faithful LVI detection. In order to study the efficacy of the sensor network, an impact localization algorithm based on peak strain amplitude from the sensor bonded to the structure was used in this study. Further the detection efficiency of the algorithm has been improved using weighted average value around the peak amplitude of strain experienced by the sensor. We found that for the high energy (~35 J) LVI the maximum distance error (Euclidian distance) was 50 mm for 80% of total trail case. Furthermore, we have developed and compared the relative performance of the algorithm cited in the literature, will be presented in PART-II of the same Journal

Stacked Hybridization to Enhance the Performance of Artificial Neural Networks (ANN) for Prediction of Water Quality Index in the Bagh River Basin, India

Data availability statement: The data pertaining to this study have not been deposited in a publicly accessible repository, given that all relevant data are thoroughly detailed in the article or appropriately cited in the manuscript.Water quality assessment is paramount for environmental monitoring and resource management, particularly in regions experiencing rapid urbanization and industrialization. This study introduces Artificial Neural Networks (ANN) and its hybrid machine learning models, namely ANN-RF (Random Forest), ANN-SVM (Support Vector Machine), ANN-RSS (Random Subspace), ANN-M5P (M5 Pruned), and ANN-AR (Additive Regression) for water quality assessment in the rapidly urbanizing and industrializing Bagh River Basin, India. The Relief algorithm was employed to select the most influential water quality input parameters, including Nitrate (NO3-), Magnesium (Mg2+), Sulphate (SO42-), Calcium (Ca2+), and Potassium (K+). The comparative analysis of developed ANN and its hybrid models was carried out using statistical indicators (i.e., Nash-Sutcliffe Efficiency (NSE), Pearson Correlation Coefficient (PCC), Coefficient of Determination (R2), Mean Absolute Error (MAE), Root Mean Square Error (RMSE), Relative Root Square Error (RRSE), Relative Absolute Error (RAE), and Mean Bias Error (MBE) and graphical representations (i.e., Taylor diagram). Results indicate that the integration of support vector machine (SVM) with ANN significantly improves performance, yielding impressive statistical indicators: NSE (0.879), R2 (0.904), MAE (22.349), and MBE (12.548). The methodology outlined in this study can serve as a template for enhancing the predictive capabilities of ANN models in various other environmental and ecological applications, contributing to sustainable development and safeguarding natural resources.No funding was received for conducting this study

Finite Element Analysis of Inter Spar Ribs of Composite Wing of Light Transport Aircraft against Brazier Load

Inter spar ribs of wing of a transport aircraft is ubjected to various types of loads. One of the loads that poses stability problem to the interspar ribs of a wing is brazier load, which arises due to flexure of the wing. This paper describes about the finite element analysis of inter spar ribs of a wing at local level against brazier load. This study has been taken place while converting metal wing in to composite wing. The objective of this study is to reduce the weight penalty to the maximum possible extent by removing material wherever feasible. This paper is limited to discuss about the linear buckling analysis of ribs against brazier load. The buckling factor of ribs under consideration are reported in terms of square root times the eigenvalue obtained from finite element analysis, which represent the nonlinear effect of bending moment on brazier load. This study has helped to reconfigure/redesign the interspar ribs of wing. This has led to substantial weight saving of 2.85 Kg which accpunts 15.77% reductions of total mass of inter spar ribs

Novel Design of Cocured Composite ‘T’ Joints with Integrally Woven 3D Inserts

Composites can be exploited to their full potential when cocured, wherein different parts are made and bonded together in a single cure operation to realise an integral structure. The key element in a typical cocured construction is T-joint, which forms the primary load transfer mechanism between the skin and stiffener in a structural assembly. T-joints are particularly vulnerable for pull off loads and researchers are looking at various techniques to improve the pull strength viz. stitching, tufting, 3D weaving, multilayer weaving, 3D braiding and the like. The present work uses a novel technique to improve the strength of T-joints by employing a hybrid design wherein an integral 3D ‘T’ insert is interleaved with a conventional T-joint. Inserts were woven using 3K and 6K carbon tows and incorporated in T-joints using CSIR-NAL proprietary process called ‘Vacuum Enhanced Resin Infusion Technology (VERITy)’ process. Several configurations of T-joints were tested in an UTM in the pull mode till the failure to assess the efficacy of integrally woven 3D inserts. It was observed that the initial failure load was nearly the same across the various T-joint configurations tested whereas the maximum failure loads were quite different. The normalised strength of T-joints with integrally woven 3D inserts in pull off mode was enhanced by about 30% when compared T-joints without the insert and thus vindicating the usage of integrally woven 3D insert in a cocured T-joint. The insert is conceived in such a way that it can be easily incorporated in the design of cocured structures

Damage Growth Studies on Composite Flap Structures Under Fatigue Loading

The rib-skin construction using carbon fiber composites has been an attractive design option for aircraft control surfaces like aileron, elevator, rudder, flap etc. The major concern in such structures is the debonding between skin and rib flange which can occur due to low velocity impacts like tool drops, run way debris etc. Such debonds which occur in service are barely visible and may not get detected till the next inspection schedule. The integrity of the structure in the intervening period is of great concern to the designers. In the present work, the structural integrity of a composite flap structure having multiple debonds at the rib skin interfaces under fatigue loading has been addressed. The flap is subjected to cyclic loading at design limit load for 110000 cycles using a whiffle tree mechanism. The strains have been monitored at different locations to understand the behaviour of structure during the test using strain gauges and Fiber Bragg Grating (FBG) sensors. Ultrasonic A-scan was used to monitor the defect growth after each block of 1000 cycles. The growth of debonds was not significant during the fatigue testing. The strain levels did not change appreciably throughout the test period indicating the damage tolerance capacity of the flap structure. The low growth of debonds was attributed to the low level of strains in the structure since the flap design is driven by stiffness considerations