Flexural Behavior Research Articles

Comparative Analytical study of GFRP strengthened Deep Beams

Abstract: Deep beams play a very significant role in the design of mega and as well as small structures. Sometimes for architectural purposes, buildings are designed without using any columns for a very large span. The flexural behavior of deep beams with and without web reinforcement and strengthened with GFRP strips and steel fiber-reinforced concrete (SFRC) was investigated in this paper. CFRP has been used extensively for strengthening of RCC structures. In this study GFRP strips are used as an alternative. GFRP strips have been used in place of CFRP strips. The four-point flexural response of one reference beam strengthened with high-performance fiber-reinforced concrete was investigated by carrying out a FEM analysis using ANSYS software and comparing it with theoretical calculation done as per ACI code using Strut Tie Model. The analytical and theoretical data (strain, load, etc.) are compared and discussed. For comparison the results from an earlier study [11] on CFRP strengthened deep beams is used as a reference. The RC and SFRC deep beams showed formation of compression struts. The deflection and shear stress values for FRC deep beam were comparatively lesser than RC deep beam and an increase in load carrying capacity was observed with reduced deflection. It was observed that the GFRC strengthened deep beams produced better results than the CFRC strengthened beams. SFRC-GFRP strengthened deep beam showed the highest ultimate load value compared to other options. While values of deflection were reduced in both GFRP strengthened RC and SFRC deep beams. RC-GFRP, SFRC- GFRP strengthened and SFRC showed reduction in shear stresses compared to RC deep beam.The study suggests that GFRP strengthened FRC deep beam is a better alternative to RC deep beams as it has better ultimate strength and shear stress values compared to RC deep beams and GFRP being an economical and sustainable option can be an alternative to strengthening with CFRP wraps

Flexural Strength, Fatigue Behavior, and Microhardness of Three-Dimensional (3D)-Printed Resin Material for Indirect Restorations: A Systematic Review

The purpose of this systematic review was to evaluate three mechanical properties of 3D-printed resins for indirect restorations according to published scientific evidence. This systematic review was conducted according to the PRISMA statement (preferred reporting elements for systematic reviews and meta-analyses). The search was performed by two investigators, (DD) and (VB), and a third (AC) resolved disagreements. Articles were searched in four digital databases: PubMed, EBSCO, Lilacs, and Science Direct, starting on 18 February 2024. As 3D-printing technology has shown significant advances in the last 5 years, the review was conducted with a publication year range between 2019 and 2024, in English language and included in vitro articles on the mechanical properties of flexural strength, fatigue behavior, and microhardness of 3D-printed materials for temporary or definitive restorations. MeSH terms and free terms were used for the titles and abstracts of each article. Finally, the QUIN tool was used to assess the risk of bias. In the main search, 227 articles were found, of which 20 duplicates were excluded, leaving 207 articles; of these, titles and abstracts were read, and 181 that did not meet the eligibility criteria were eliminated; of the remaining 26 articles, 1 article was eliminated for not presenting quantitative results. Regarding publication bias, 6 of the 25 articles had a low risk of bias, 18 had a medium risk of bias, and 1 had a high risk of bias. It may be concluded that 3D-printed resins have lower flexural strength, fatigue behavior, and microhardness than other resin types used for the fabrication of temporary and permanent restorations. The type of 3D printer and polymerization time could be factors that significantly affect the flexural strength, fatigue behavior and microhardness of 3D-printed resins. Based on existing evidence, it should be considered that additive technology has promising future prospects for temporary and permanent dental restorations.

Using Artificial Neural Networks to Predict the Bending Behavior of Composite Sandwich Structures

The refinement of effective data generation methods has led to a growing interest in using artificial neural networks (ANNs) to solve modeling problems related to mechanical structures. This study investigates the modeling of composite sandwich structures, i.e., structures made up of two laminated composite face sheets sandwiching a lightweight honeycomb core. An ANN was utilized to predict structural deflection and face sheet stress with low computational cost. Initially, a three-point load mode was used to determine the flexural behavior of the composite sandwich structure before subsequently analyzing the sandwich structure using the Monte Carlo sampling tool. Various combinations of face sheet materials, face sheet layer numbers, core types, core thicknesses and load magnitudes were considered as design variables in data generation. The generated data were used to train a neural network. Subsequently, the predictions of the trained ANN were compared with the outcomes of a finite element model (FEM), and the comparison was extended to real structures by conducting experimental tests. A woven carbon-fiber-reinforced polymer (WCFRP) with a Nomex honeycomb core was tested to validate the ANN predictions. The predictions from the elaborated ANN model closely matched the FEM and experimental results. Therefore, this method offers a low-computational-cost technique for designing and optimizing sandwich structures in various engineering applications.

Experimental Study on Flexural Behaviour of Prefabricated Steel-Concrete Composite I-Beams Under Negative Bending Moment: Comparative Study.

The issues of numerous steel beam components and the tendency for deck cracking under negative bending moment zones have long been challenges faced by traditional composite I-beams with flat steel webs. This study introduces an optimized approach by modifying the structural design and material selection, specifically substituting flat steel webs with corrugated steel webs and using ultra-high-performance concrete for the deck in the negative bending moment zone. Three sets of model tests were conducted to compare and investigate the influence of deck material and web forms on the bending and crack resistance of steel-concrete composite I-beams under a negative bending moment zone. The findings indicate that, compared to a conventional steel-normal concrete composite I-beam, incorporating ultra-high performance concrete into the negative bending zone enhances the cracking load by 98%, resulting in finer and denser cracks, and improves the ultimate bearing capacity by approximately 10%. In comparison to the composite I-beam with flat steel webs, the longitudinal stiffness of the composite I-beam with corrugated steel webs is smaller, which can further enhance the bridge deck's resistance to cracking in the negative bending moment zone, and maximize the steel-strengthening effect of the lower flange of the steel I-beam. Based on the findings of this study, it is recommended to use steel ultra-high-performance concrete composite I-beams with corrugated steel webs due to their superior crack resistance, bending strength, and efficient material utilization.

Flexural Response Comparison of Nylon-Based 3D-Printed Glass Fiber Composites and Epoxy-Based Conventional Glass Fiber Composites in Cementitious and Polymer Concretes.

With 3D printing technology, fiber-reinforced polymer composites can be printed with radical shapes and properties, resulting in varied mechanical performances. Their high strength, light weight, and corrosion resistance are already advantages that make them viable for physical civil infrastructure. It is important to understand these composites' behavior when used in concrete, as their association can impact debonding failures and overall structural performance. In this study, the flexural behavior of two designs for 3D-printed glass fiber composites is investigated in both Portland cement concrete and polymer concrete and compared to conventional fiber-reinforced polymer composites manufactured using a wet layup method. Thermogravimetric analysis, volume fraction calculations, and tensile tests were performed to characterize the properties of the fiber-reinforced polymer composites. Flexural testing was conducted by a three-point bending setup, and post-failure analysis was performed using microscopic images. Compared to concretes with no FRP reinforcement, the incorporation of 3D-printed glass-fiber-reinforced polymer composites in cementitious concrete showed a 16.8% increase in load-carrying capacity, and incorporation in polymer concrete showed a 90% increase in flexural capacity. In addition, this study also provides key insights into the capabilities of polymer concrete to penetrate layers of at least 90 microns in 3D-printed composites, providing fiber bridging capabilities and better engagement resulting in improved bond strength that is reflected in mechanical performance. The polymer material has a much lower viscosity of 8 cps compared to the 40 cps viscosity of the cement slurry. This lower viscosity results in improved penetration, increasing contact surface area, with the reinforcement consequently improving bond strength. Overall, this work demonstrates that 3D-printed fiber-reinforced polymer composites are suitable for construction and may lead to the development of advanced concrete-based reinforced composites that can be 3D-printed with tailored mechanical properties and performance.

Effect of High Percentages of Coated Recycled Aggregates on the Flexural Behavior of Reinforced Concrete Beams

Currently, the use of recycled aggregates (RA) in new concrete is allowed by several international regulations, although their replacement is limited to low percentages of the coarse fraction. In order to increase the percentage of RA, several authors have studied different processes to improve the microstructure of its surface. Therefore, it is necessary to analyze whether the current standards simulate the structural behavior of concretes with high percentages of RA. For this purpose, beams with 0%, 50% and 100% RA replacement coated with recycled binder paste (RBP) were made and their behavior was compared with the equations of the Eurocode 2 and ACI 318-19 code. As a result, we found that when 100% coated RA was used, the reduction in compressive strength was only 12.73%, with similar cracking patterns observed in RA beams across all series. In addition, the load capacity of the beams with RA was higher than the theoretical values provided by the codes. Finally, the experimental critical deflection was higher than that calculated by the code equations. Thus, it is recommended that these higher deflections be taken into account at the time of design.

Enhancing the flexural behavior of GFRP single‐lap co‐cure joints reinforced with multi‐reinforcements

AbstractThe investigation focused on the glass fiber‐reinforced polymer (GFRP) composite co‐cure single lap joint (CC‐SLJ) that incorporates graphene nanoparticles (GNP) in epoxy and carbon fiber‐reinforced polymer (CFRP) Z‐pin reinforcement. The flexural test indicated that the integration of GNP and CFRP‐Z‐pin within the inner and outer layers of SLJ leads to improvement in flexural strength. The flexural strength of CC‐SLJ reinforced with GNP/epoxy and Z‐pin reinforcement reaches 145.02 MPa under static loading, with an improvement of 69.55% over the unreinforced SLJ. The SLJ under static loading with GNP/epoxy and graphene incorporated Z‐pin reinforced with demonstrate a significant improvement in flexural strength of 150.34 MPa, with an improvement of 71.22% over the unreinforced SLJ. Fractography revealed that the incorporation of GNP and Z pins into the SLJ enhances interfacial bonding between the adhesive and adherend, increases surface roughness, improves pin pull‐out resistance, and influences crack formation.Highlights The co‐cure technique is used to fabricate single‐lap GFRP composite joints. Carbon fiber‐reinforced polymer Z‐pin reinforced with GNP/epoxy adhesive. SLJ flexural strength was higher in 1.25 wt% of GNP and 2.5 vol% 90°/Z‐pin. Multiple reinforcements used in SLJ to achieve its maximum flexural strength. Failure analysis was conducted using microscopes and FESEM images.

Secondary bonded and co‐bonded CFRP composite joints with innovative lamination technique: Flexural and failure analysis

AbstractAdhesively bonded techniques effectively fuse the structural components in an assembly in aerospace applications. The co‐bonding is more effective than secondary bonding for joining fuselage frames to skins, wing ribs, and spars to skin joints. The flexural behavior and failure analysis of a carbon fiber‐reinforced polymer composite single‐lap joint is one crucial factor in aerospace applications. This research involved the fabrication of co‐bonded carbon fiber‐reinforced polymer composite single‐lap joints utilizing the vacuum bag hand lay‐up method, incorporating geometric modification techniques, including interleaved and covered lamination. The flexural strength was examined through a three‐point bending test. The results indicate that the secondary bonded with covered lamination techniques has attained the maximum flexural strength compared to others. The values are 80% higher than the neat secondary bonded joints. Moreover, the carbon fiber‐reinforced polymer composite single lap joint samples were examined for failure analysis using the ASTM D5573 standard. Furthermore, these geometric modifications in CFRP composite joints confirmed the significant enhancement in experimental results with less than 5% error rates.Highlights Carbon fiber‐reinforced polymeric (CFRP) joints were made utilizing interleaved and covered lamination methods. SB and CB methods were utilized to fabricate the CFRP composite joints. CL‐SBT exhibits high flexural strength (639 MPa) and modulus (45.94 GPa). A thin‐layer cohesive failure was observed in interleaved CFRP joints, The fiber tear failure was observed in covered lamination CFRP joints.

Numerical analysis of flexural behavior of sandwich beams using the FGM approach

Analytical modeling to predict the flexural behavior of sandwich beams using a triangular finite element model, the Triangular Plate Finite Element with Airy Function (TPAF). The originality of this model lies in the use of the deformation approach, which comprises three nodes and three degrees of freedom per node (one translation Wi and two rotations θxi and θyi). The main aim of this work is to validate the model by comparison with other solutions, in particular by means of an analytical prediction based on layer theory and the results obtained using CSB software. The originality of this study lies in the fact that the mechanical properties vary according to an exponential function along the height of the FGM section and remain constant in the other parts of the different composite sections. Tabular and graphical results are presented to illustrate the impact of deffrents, such as geometric factors (thickness configurations and length/thickness ratios), as well as boundary conditions and loads, on the static behavior of the beam.

Experimental study on the flexural behavior of ferrocement slab panels with supplementary cementitious silica fume and fiber materials

Ferrocement is a composite construction material with slender sections or panels, a rich cementitious mortar, and steel wire mesh as its principal reinforcing agent. The mortar matrix is designed to achieve optimal strength, density, impermeability, and workability, minimizing void formation and preventing map cracking. A study evaluated the workability and flexural strength of mortars prepared using three types of fine aggregates: Badarpur sand, Yamuna River sand, and Kilned Brick Powder. The mortar classifications included conventional mortar compositions (MCS), mortars with flyash and Silica Fume (MFSS), and mortars with flyash, silica fume, and human hair (MFSHS). The results showed that mixes incorporating these materials significantly improved workability, with MFSS-2 (Portland cement, Yamuna sand, plus 10% FA and 6% SF) showing the highest increase (42.50%). The high-strength formulations with supplementary materials were superior in terms of stiffness and structural integrity, with MFSHS-1 (Portland cement, Badarpur sand, 10% FA, 6% SF, and 1% HH fiber) showing the least deflection for any given load. The addition of 1% human hair fibers in the mortar matrix improved flexural strength in panels, acting as micro-reinforcements, enhancing the tensile strength alongwith mortar ductility.

A Numerical and Theoretical Investigation of the Flexural Behavior of Steel–Ultra-High-Performance Concrete Composite Slabs

A Numerical and Theoretical Investigation of the Flexural Behavior of Steel–Ultra-High-Performance Concrete Composite Slabs

Pioneering the next frontier in construction with high-strength concrete infused by nano materials

ABSTRACT The advancement of nano engineering technology plays a major role in the cementitious materials especially graphene oxide which got high attention. In this research the addition of graphene oxide, silica fume and flyash with various mix proposition in partial replacement of cement have be investigated for mechanical properties of concrete which is the macro level (workability, strength behavior, flexural behavior, water absorption, porosity, and durability) and micro level structural analysis (SEM analysis). Polycarboxylate ethers are used as super plasticizers to offset this decrease, which substantially improves the concrete’s workability. Silica fume and fly ash are utilized in fixed proposition of 10% of silica fume and 10% of fly ash, by weight, to enhance the strength of concrete. After conducting various tests, it has been determined that the optimal combination involves a 10% replacement of both silica fume and fly ash for ordinary Portland cement, particularly grade 53, resulting in superior outcomes. Addition to its varying percentages from 0, 0.01, 0.02, 0.03, 0.04 and 0.05% of Graphene oxide used to find the optimum percentage of GO by weight of ordinary Portland cement to obtain high strength. The optimum percentage of grapheme oxide to be replaced with cement is 0.04%.

Influence of recycled spent abrasive particle addition on the mechanical properties of kenaf fiber-reinforced hybrid polymer composites

ABSTRACT Worn-out or used abrasive particles from abrasive water jet machining are found to be wasted without recycling in most cases, as they contain different metal and non-metal particles with respect to their application. The abrasive waste obtained from abrasive water jet machining can be gainfully utilized in various engineering applications. Owing to the same, the present work attempts to recycle and reuse the same for manufacturing kenaf fiber-reinforced hybrid polymer composites. Polymer composites were synthesized using the hand lay-up method, incorporating kenaf natural fibers, epoxy resin, and recycled spent abrasive particles. The spent abrasive particles collected from abrasive water jet machining were chosen as the filler material, and they were mixed in different weight percentages with epoxy resin to fabricate a kenaf fiber-reinforced hybrid polymer composite. The effects of recycled spent abrasive particle filler addition on the tensile, flexural, and impact behaviour of the synthesized polymer hybrid composites were examined. Fractured samples with different filler compositions were examined using a scanning electron microscope to probe the failure patterns. The experimental results revealed positive trends in the enhancement of mechanical properties with the inclusion of the spent abrasive particles.

Flexural behaviour of recycled ceramic aggregate concrete-filled double skin round steel tubes

Flexural behaviour of recycled ceramic aggregate concrete-filled double skin round steel tubes

Numerical and theoretical investigation for the flexural behaviour of geopolymer concrete beams reinforced with hybrid FRP /steel bars

Numerical and theoretical investigation for the flexural behaviour of geopolymer concrete beams reinforced with hybrid FRP /steel bars

Size effect on the flexural behavior of UHPFRC beams and RC beams strengthened with UHPFRC

Size effect on the flexural behavior of UHPFRC beams and RC beams strengthened with UHPFRC

Flexural behaviour of reinforced concrete beams strengthened with ultra-high ductility MPC-based composites

Flexural behaviour of reinforced concrete beams strengthened with ultra-high ductility MPC-based composites

Data Driven Framework with Graphical User Interface for Predicting Flexural Behavior of FRCM Strengthened RC Beams

In this study, the flexural capacity of reinforced concrete (RC) beams strengthened with fiber-reinforced cementitious matrices (FRCM) was computed using machine learning (ML) algorithms including: (i) adaptive neuro-fuzzy inference system (ANFIS), (ii) artificial neural network (ANN), and (iii) extreme gradient boosting (XGBoost). A total of 198 pertinent experimental datasets were compiled and included six types of FRCM composites (PBO, carbon, glass, basalt, coated carbon, and combined glass and carbon). The considered input parameters comprise the beam cross-sectional details, area of tensile and compressive steel reinforcement, mechanical properties of FRCM composite, and concrete compressive strength. To assess the reliability of ML models, four existing analytical models and one established standard guideline were used for comparison. Moreover, six statistical metrics were employed, along with an overfitting analysis, to determine the best-fitting model. Graphical fitting of the optimal model was depicted using the Taylor diagram, violin plot, as well as multi-panel histogram plot. Based on both graphical and statistical metrics, the XGBoost model attained the highest precision compared to all analytical and ML-based models. The correlation coefficient and MAPE of the XGBoost model were 0.9977 and 2.98%, respectively. To interpret the influence of individual parameters on the flexural strength of the FRCM-strengthened RC beams, a feature importance plot based on SHAP explanatory theory was deployed. Ultimately, a user-friendly graphical interface was developed and made accessible to aid practicing engineers in estimating the flexural strength of FRCM-strengthened RC beams, offering an effective alternative to complex design procedures.

Structural Performance of Reinforced Concrete Beams with Steel Fibres as Secondary Reinforcement: Experimental and Pre-peak Numerical Modelling

This research consists of an experimental and a numerical investigation into improving the structural performance of reinforced concrete (RC) beams by incorporating hooked-end steel fibres. Experimentally, steel fibres were added to the concrete matrix of 80 mm × 180 mm × 1500 mm RC beams with fibre contents of 0%, 0.5%, and 1%, without replacing traditional reinforcement bars. Each beam underwent a four-point flexural test using a hydraulic press under static loading to evaluate the influence of fibres on flexural behaviour. The numerical analysis aimed to model the macro-scale flexural behaviour of RC beams using a 3D finite element approach in ABAQUS. Challenges in modelling steel fibres include their discrete nature and computational demands due to intricate meshing and convergence issues. The Simplified Concrete Damaged Plasticity Model was used to characterize the compressive and tensile behaviours of plain and steel fibre reinforced concretes. Nonlinear finite element analysis was performed to predict pre-peak load versus mid-span deflection and crack propagation. The model, which does not explicitly simulate steel fibres, was validated against experimental data, showing strong agreement and confirming its effectiveness in capturing the flexural behaviour of steel fibre reinforced concrete beams. Experiments Results showed that steel fibres enhance the flexural performance. Beams with steel fibres exhibited higher first crack loads, ultimate loads, flexural strengths, and toughness. Additionally, the fibres increased crack numbers, reduced crack spacing and length, and improved post-cracking behaviour. The simulation results were subsequently validated against experimental data. The results of the numerical finite element analysis were in good agreement with those of the experiments.

Feasibility study of scapula bone as a next-generation material for biomedical applications

ABSTRACT This study investigates the influence of material thickness on the mechanical properties, specifically flexural and tensile properties, of scapula bone specimens from Deccani breed sheep in India. A three-point bending test and a tensile test were conducted on samples with varying thicknesses (1, 2 and 5 mm), and the flexural strength, flexural modulus, ultimate load, tensile deformation and von Mises stress were measured. Thicker specimens exhibited higher flexural properties than thinner counterparts. Statistical analysis using one-way ANOVA confirmed that material thickness significantly impacted the flexural and tensile properties of the samples. Additionally, a simulation analysis was performed using ANSYS Workbench to validate the experimental results and provide insights into the tensile and flexural behaviour of the specimens. The findings suggest that thicker samples are better equipped to handle bending stresses and tensile loads and are more suitable for applications requiring resistance to bending loads, stiffness, load-bearing capacity and tensile strength.