Prediction of natural frequency of basalt fiber reinforced polymer (FRP) laminated variable thickness plates with intermediate elastic support using artificial neural networks (ANNs) method

The paper is focused on the application of artificial neural networks (ANNs) in predicting the natural frequency of basalt fiber reinforced polymer (FRP) laminated, variable thickness plates. The author has found that the finite strip transition matrix (FSTM) approach is very effective to study the changes of plate natural frequencies due to intermediate elastic support (IES), but the method difficulty in terms of, a lot of calculations with large number of iterations is the main drawback of the method. For training and testing of the ANN model, a number of FSTM results for different classical boundary conditions (CBCs) with different values of elastic restraint coefficients (KT) for IES have been carried out to training and testing an ANN model. The ANN model has been developed using multilayer perceptron (MLP) Feed-forward neural networks (FFNN). The adequacy of the developed model is verified by the regression coefficient (R2) and Mean Square error (MSE) It was found that the R2 and MSE values are 0.986 and 0.0134 for train and 0.9966 and 0.0122 for test data respectively. The results showed that, the training algorithm of FFNN was sufficient enough in predicting the natural frequency in basalt FRP laminated, variable thickness plates with IES. To judge the ability and efficiency of the developed ANN model, MSE has been used. The results predicted by ANN are in very good agreement with the FSTM results. Consequently, the ANN is show to be effective in predicting the natural frequency of laminated composite plates

Cracking behavior of basalt fibre reinforced polymer‐reinforced concrete: An approach for the determination of crack spacing and crack width

The limitation of the crack width is of central importance for the design in the serviceability limit state. For FRP‐reinforced concrete members, the crack width has to be limited for service condition in use and not due to corrosion protection. In this paper, an experimental program of pull‐out tests and slender concrete cylinders with basalt fiber‐reinforced polymer rebars under centric tension load is presented. The used basalt fiber‐reinforced polymer rebars are sand coated and have in addition a helically wrapped thread for a decent profiling. Equations to calculate crack spacing and crack width of FRP‐reinforced concrete is derived and calibrated with the obtained experimental results. Finally, the equations are verified with experimental data from other authors and a crack model is given for reinforced concrete members with FRP rebars with a helically wrapped and sand coated surface

Thermographic non-destructive evaluation for natural fiber-reinforced composite laminates

Natural fibers, including mineral and plant fibers, are increasingly used for polymer composite materials due to their low environmental impact. In this paper, thermographic non-destructive inspection techniques were used to evaluate and characterize basalt, jute/hemp and bagasse fibers composite panels. Different defects were analyzed in terms of impact damage, delaminations and resin abnormalities. Of particular interest, homogeneous particleboards of sugarcane bagasse, a new plant fiber material, were studied. Pulsed phase thermography and principal component thermography were used as the post-processing methods. In addition, ultrasonic C-scan and continuous wave terahertz imaging were also carried out on the mineral fiber laminates for comparative purposes. Finally, an analytical comparison of different methods was give

Finite Element Modelling And Analysis Of Rc Beams Strengthened For Flexure Using BFRP Fabrics

The increasing cost of new infrastructure in addition to the gradual decline in the structural integrity of current aging infrastructure has necessitated studies for sustainable materials for strengthening concrete structures. Extensive experimental and numerical studies using carbon fiber reinforced polymers (CFRP) and glass fiber reinforced polymers (GFRP) for strengthening concrete structures have concluded on their immense efficiency in increasing the ultimate capacity of such structures. Basalt fiber reinforced polymer (BFRP), however, is a relatively new material in the construction industry with limited experimental and numerical studies. This study presents a non-linear numerical analysis on reinforced concrete beams strengthened with basalt fiber reinforced polymer (BFRP) fabrics using finite element (FE) software, Abaqus. The load-deflection behavior, failure modes, ductility index and cracking patterns of the beams were analysed and compared to experimental results obtained from literature. The FE model was observed to have a good correlation with the test results and was able to predict the elastic and plastic behavior of the concrete beams. The results of the FE analysis indicate that BFRP fabrics were able to increase the load capacity of the strengthened beams up to 120% and the ductility up to 67% over the control beam. However, the strengthening scheme must remain within the optimum number of layers to ensure that the beams do not experience sudden and brittle failure

Burst Strength Analysis of Composite Pressure Vessel using Finite Element Method

Currently, composite pressure vessels are widely utilized in industries like the oil and gas industry and etc. The demand for such vessels is constantly increasing due to their better strength properties than conventional metallic pressure vessels which are heavy and highly prone to corrosion. Thus, this prompts for a more cost effective and sustainable method to assess structural integrity of a composite pressure vessel which could minimize burst failures during operations. However, the main problems are the lack of literatures and research works for design optimization as well as the lack of defined materials for composite pressure vessel construction. Hence, the main objectives of this project are to perform burst failure analysis and to conduct parametric burst failure studies on composite pressure vessels using finite element method. The main scopes of this project are the adaptation of failure criteria like Tsai-Wu, Tsai-Hill and maximum stress in performing burst failure analysis as well as parametric studies on the optimal filament orientation angle and materials used for the liner and shell of a composite pressure vesse

Application of basalt-FRP bars for reinforcing geotechnical concrete structures

The fiber reinforced polymer (FRP) bars have become a useful substitute for conventional reinforcement in civil engineering structures for which load capacity and resistance to environmental influences are required. They are often used in concrete structural elements exposed to strong environmental aggression, such as foundations, breakwaters and other seaside structures, road structures and tanks. The basalt fiber-reinforced polymer (BFRP) is the most recently FRP composite, appearing within the last decade. Due to their mechanical properties different from steel bars, such as higher tensile strength and lower Young's modulus, BFRP bars are predestined for use in structures for which the ultimate limit state is rather decisive than serviceability limit state. Experimental tests were carried out to assess the influence of static long-term loads and cyclic freezing/thawing on the behaviour of concrete model beams with non-metallic reinforcement. The bars made of basalt fiber reinforced polymer (BFRP) and hybrid (basalt and carbon) fiber reinforced polymer (HFRP) were used as non-metallic reinforcement. The mechanical properties of both types of bars were also determined

Experimental and analytical study of bond between basalt FRP bars and geopolymer concrete

This paper presents an experimental and analytical study of the bond behaviour of basalt fibre reinforced polymer (BFRP) bars in geopolymer concrete (GPC). Pull-out tests were conducted on ribbed BFRP bars embedded in GPC cubes considering different bar diameters (6, 8 and 10 mm) and embedment lengths (5db, 10db and 15db) to investigate their effects on bond behaviour in terms of bond-slip response, bond strength and failure mechanisms. Results indicate that the chemical adhesion is low, and the bond is mainly dependent on mechanical interlocking which stopped when pullout occurred by local crushing of the GPC with the BFRP ribs remaining undamaged, suggesting high rib shear strength. A theoretical bilinear model was used to describe the local bond-slip relationship and the bond interface properties. There exists nonlinear bond stress distribution, especially for longer embedment lengths and lower load levels with a bond stress concentration factor of 3.9. A parametric study was performed to estimate the influences of bar diameter, embedment length and elastic modulus on maximum pull-out load, based on which the load transfer mechanisms between BFRP bars and GPC were explored, and a formula for predicting the bond strength was proposed in comparison with experimental data

THE INFLUENCE OF TECHNOLOGICAL FACTORS ON THE PROPERTIES OF BASALT FIBER WHEN USED IN THE MANUFACTURE OF FLEXIBLE HEAT AND SOUND INSULATING PRODUCTS

Analysis of energy efficiency and operational safety of technological equipment of industrial enterprises, engineering networks, buildings and structures, building structures in many sectors of the economy, including the housing and industrial sectors, causes interest in the use of high-tech, environmentally friendly heat and sound insulation materials with enhanced performance properties. One of the relevant representatives of these materials is basalt fibers and their use as raw materials in the production of flexible heat and sound insulating products. It is known that the chemical composition of the initial melt equally affects the physicochemical and mechanical properties of basalt fibers. The main influence factors, including the chemical composition, are the thermal past of the melt, the method for producing basalt fiber and the conditions for the formation of its structure. These factors determine the structural characteristics of the fiber and, as a consequence, its physicochemical characteristics. The degree of fiber strength is directly determined by its chemical composition and production method. The greatest strength of the fiber is obtained by ensuring the perfect fiber structure in the absence of ruptures of siliceous chains

Experimental studies on the shear capacity of sea sand concrete beams with basalt fiber-reinforced polymer bars

Basalt fiber-reinforced polymer (BFRP) bars can replace steel bars in sea sand concrete structures to prevent the corrosion of steel by chloride ions; thus, sea sand can be directly added to concrete material in construction. Shear tests on 16 sea sand concrete beams with BFRP bars (including ten beams with stirrups and six beams without stirrups) are performed, and their failure modes, shear capacities and influencing factors are analyzed. The results reveal two main failure modes for sea sand concrete beams with BFRP bars: bending failure and shear-compression failure. The shear capacity increases with the concrete strength and stirrup ratio but decreases with an increased shear-span ratio, and the longitudinal reinforcement ratio has an insignificant effect on shear capacity