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The bonding performance and formation of the interphase region between fiber and matrix have significant effects on the strength and durability of composites. A new approach, involving combined experimental and numerical analyses, has been developed to avoid the shortcomings and scattering associated with local experimental methods. For this purpose, tensile tests are performed on specimens fabricated from a single glass fiber and epoxy resin. The elongations for specified lengths are measured using the digital image correlation (DIC) technic. The size of the fiber diameter and specimen section are also measured from SEM images. The obtained experimental displacements for micro tensile tests are used in an inverse elastic finite element solution to obtain the interphase elastic modulus. It is shown that, considering the interphase thickness of 1.0 μm that is more realistic, the interphase elastic modulus is in the range of 12 ∼ 19 GPa. However, the performed sensitivity analysis shown that considering interphase thickness ranging from zero to 2.0 μm the interphase elastic modulus varies between 9 and 46 GPa. It is shown that the proposed procedure can be used to obtain the overall mechanical properties of the matrix/fiber interphase in long fiber composites. [ABSTRACT FROM AUTHOR]

Although numerous investigations study the improvement of flame retardancy of epoxy resins using additives, maintaining the flame retardant (FRs) modes of action present in the resins upon transfer to composites is challenging. In this study, ammonium polyphosphate (APP) and inorganic silicate (InSi) are loaded at 10%, 30%, and 50% by weight, in a diglycidyl ether of bisphenol A (DGEBA) resin cured with dicyandiamide and transferred to bidirectional (BD) glass fiber (GF) composites. Although a 50% loading of the FRs impacts the curing kinetics of the resin system, the effect on the glass transition temperature of the resin system remains negligible compared to reactive FRs in the state of the art integrated into the resin's chemical structure. Increasing the FR content improved the heat release characteristics in both the resins and composites. However, the charring mode of action is completely suppressed in the formulation with 10% APP + InSi. A 30% concentration of the FRs restored the charring action in the composite and the GFs provide increased protective layer action upon transfer to the composites. This study highlights the importance of accounting for the changing dynamics related to processing and flame retardancy upon transferring FRs from resins to composites. [ABSTRACT FROM AUTHOR]

Users of the microbond test assume that a microbond resin droplet's properties are equivalent to a macroscale specimen. However, there is currently no standardised methodology for determining the cure state of droplet specimens used in the microbond test. In this paper, we present a technique for microbond test users to better understand the properties of thermoset droplet specimens. Utilising a conventional benchtop spectrometer, a novel sample preparation technique involving curing epoxy droplets on thin-steel filaments allowed for high-throughput determination of the microbond droplet cure state. The parity between steel filament and glass fibre microbond samples was confirmed by infrared microspectroscopy. It is shown that cure schedules used in manufacturing composite parts produced microbond droplets with degrees of cure lower than that of bulk matrix specimens subjected to an identical thermal history. Testable microbond droplets could only be prepared for commercial resin systems when introducing a room temperature pre-curing time of at least 2 h. It is concluded that microbond testing should be supported by some droplet cure state characterisation methods to ensure that interfacial effects are not artefacts of droplet sample preparation. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the moment redistribution in continuous glass fiber reinforced polymer (GFRP)-concrete composite slabs caused by concrete cracking and steel bar yielding in the negative bending moment zone. An experimental bending moment redistribution test was conducted on continuous GFRP-concrete composite slabs, and a calculation method based on the conjugate beam method was proposed. The composite slabs were formed by combining GFRP profiles with a concrete layer and supported on steel beams to create two-span continuous composite slab specimens. Two methods, epoxy resin bonding, and stud connection, were used to connect the composite slabs with the steel beams. The experimental findings showed that the specimen connected with epoxy resin exhibited two moments redistribution phenomena during the loading process: concrete cracking and steel bar yielding at the internal support. In contrast, the composite slab connected with steel beams by studs exhibited only one-moment redistribution phenomenon throughout the loading process. As the concrete at the internal support cracked, the bending moment decreased in the internal support section and increased in the mid-span section. When the steel bars yielded, the bending moment further decreased in the internal support section and increased in the mid-span section. Since GFRP profiles do not experience cracking, there was no significant decrease in the bending moment of the mid-span section. All test specimens experienced compressive failure of concrete at the mid-span section. Calculation results showed good agreement between the calculated and experimental values of bending moments in the mid-span section and internal support section. The proposed model can effectively predict the moment redistribution behavior of continuous GFRP-concrete composite slabs. [ABSTRACT FROM AUTHOR]

Hand layup was used to fabricate the glass fibre reinforced aluminium foam epoxy composites in this study. On the manufactured materials, dry sliding wear experiments were performed. The effect of wearprocess parameters such asapplying load (kg), speed (m/s), and sliding distance (m) on specific wear rate (Ws) was investigatedand the obtained results were compared with neat glass fibre reinforced epoxy composite in this work. The outcome of these results showed that specific wear rate (Ws) of glassfibre epoxy composite containing aluminium foam decreased as compared with neat glass fibre reinforced polymer composites. Experimental results showed that a minimum wear rate of 10.1 µm was attained for the sliding velocity (1.5 m/s), Applied load (2 kg), and sliding distance (1000 m) in the fabricated composite laminates. It was observed thatthe resistance to wear in glass fibre reinforced aluminium foam composite was mainly due to the bond strength between aluminium foam and epoxy. [ABSTRACT FROM AUTHOR]

This study investigates the effect of stress amplitude on the damage sensing characteristic of glass fibre reinforced (GFRP) composites under fatigue loading using the electrical resistance change (ERC) method. The electrical conductivity of GFRP composites was achieved by incorporating 0.3 wt.% multi-walled carbon nanotubes (MWCNTs) into epoxy resin by ultrasonication method. In-situ electrical resistance measurements during fatigue tests of MWCNT-filled GFRP (MWNCT/GFRP) composites were conducted at two different stress amplitudes, S = 0.6 and S = 0.5. The average stiffness losses at failure were observed as 28% and 25% for S = 0.6 and S = 0.5 respectively. The corresponding ERC ratios at failure were found as 153% and 59% for S = 0.6 and S = 0.5, respectively. A two-parameter Weibull analysis, based on the ERC ratios corresponding to 40%, 60%, 80%, and 100% (failure) fatigue life, was implemented to establish reliability curves at the two stress amplitudes. The ERC ratios at failure with a 95% reliability for S = 0.6 and S = 0.5 were determined as 64% and 23%, respectively. Finally, the remaining fatigue life and the stiffness loss of composite specimens at the ERC ratios corresponding to various Weibull reliability were found for both stress amplitudes. [ABSTRACT FROM AUTHOR]

The adhesive bonding approach is widely used in assembling of spars, stringers, ailerons, flaps, and rudders in aircraft. The present research investigated the impact of silicon carbide (SiC) nanoparticle inclusion on the shear and free vibrational behaviour of adhesively bonded single lap joints (SLJ). The shear test results showed that the inclusion of 1.5 wt.% SiC in the epoxy resin enhanced the shear behaviour of adhesively bonded SLJ. Furthermore, the failure surfaces of adhesively bonded SiC-reinforced SLJ were examined using a field emission scanning electron microscope (FESEM). The microstructural investigation of the failure surface demonstrated that the development of rougher surfaces, plastic void enlargement, and formation of shear bands in the joint region had improved adhesion among GFRP adherends. Thus, the SiC-incorporated adhesively bonded SLJ had predominant cohesive failures. Meanwhile, the SiC-free lap joint had an adhesive failure due to lower adhesion. The vibrational results avowed that 1.5 wt.% SiC-incorporated adhesively bonded SLJ has higher natural frequencies. Results also affirmed that higher wt.% SiC-incorporated joint had better modal damping values due to nanoparticle accumulation, which increased the interaction between glass fiber reinforced polymer (GFRP) adherends. [ABSTRACT FROM AUTHOR]

This paper presents a study of the flammability and thermal decomposition products of glass fiber-reinforced epoxy resin (GFRER) with the addition of cardanol-based phosphorus-containing benzoxazine monomer (CBz) and graphene and their combinations in different proportions (up to 20 wt.%). The addition of CBz alone or in combination with graphene resulted in an increase in the limiting oxygen index (LOI) and self-extinguishing in the UL-94 HB test. The flame-retardant samples had better tensile mechanical properties than the sample without additives. The differential mass-spectrometric thermal analysis (DMSTA) of the thermal decomposition products of GFRER without additives and with the addition of CBz and graphene was carried out. CBz addition promoted the thermal decomposition of high-molecular-weight products of epoxy resin decomposition in the condensed phase and at the same time decreased the time of release of low-molecular-weight thermal decomposition products into the gas phase. Graphene addition resulted in an increase in the relative intensities of high-molecular-mass peaks compared to GFRER without additives. [ABSTRACT FROM AUTHOR]

In this study, two types of composites, polybutylene terephthalate (PBT) and epoxy resin (ER), reinforced with 20% of glass fiber (GF) are used as the comparative research objects. Their mechanical properties after thermal aging at 85~145 °C are evaluated by tensile strength and fracture morphology analysis. The results show that the composites have similar aging laws. The tensile strength of GF/PBT and GF/ER decrease gradually with the increase of aging temperature, while their elastic moduli are independent of the thermal treatment temperature. Scanning electron microscopy study of the fracture surface shows that separation of glass fiber from PBT and ER matrix becomes more obvious at higher aging temperature. The fibers on the matrix surface appear clear and smooth, and the whole pulled out GFs can be observed. As a main mechanical strength degradation mechanism, the deterioration of interface adhesion between the matrix and GF is discussed. A large difference in coefficients of thermal expansion of the matrix and GF is a main factor of the mechanical degradation. [ABSTRACT FROM AUTHOR]

Highlights In this work, silicone polymer (PSOL)/glass fiber (GF)/epoxy (EP) composites were prepared by employing PSOL as interfacial modifier into GF/EP composites. The mechanical and dynamic mechanical properties of the composites were investigated to determine the optimal PSOL content. The effect of PSOL on the wettability of EP on GF was investigated. The micromorphology of the GF/EP composites was also examined by scanning electron microscope. The results demonstrate that the interfacial bonding between GF and epoxy resin was improved significantly by the addition of PSOL. Specifically, the interlaminar shear strength, tensile strength, elongation at break, and blending strength of the PSOL/GF/EP composites increased by 9.28%, 13.61%, 12.66%, and 19.22%, respectively. Moreover, the original thermal stability of the composites was improved by the incorporation of PSOL. This study highlights the effectiveness of PSOL as an interfacial modifier, enhancing the overall performance of GF/EP composites while improving their thermal stability. Silicone polymer (PSOL)/glass fiber (GF)/epoxy (EP) composite material is made of glass fiber and epoxy resin by hand paste molding. Silicon polymers as interface modifiers can improve the interface between glass fiber and epoxy resin. PSOL/GF/EP composites have good mechanical properties. The glass transition temperature of GF/EP composites was increased by silicon polymer. [ABSTRACT FROM AUTHOR]

The sandwich panels are widely used in many industrial applications due to their high mechanical properties. Their core design is most important parameter in enhancing their mechanical strength. Flexibility in the design of the core structure leads to the achievement of high strength and light structures. In this paper, the results of the optimized geometry in the previous work are used to investigate the capability of the core geometry design with different materials. Therefore, using the different materials, the peak enhancement of strength-to-weight ratio in sandwich panels besides core behavior during pressure testing are investigated. To this end, a new lattice core is brought forth as the first level; then, three types of materials including AL3105, glass, and innegra fiber/epoxy composites are used to fabricate the cores, in order to compare the compressive strength and the peak. The Nano-clay cloisite 20A is also utilized in construction of sandwich panels. The result indicates that the AL3105 lattice core has the highest strength-to-weight ratio, while the innegra fiber composite core has the highest toughness. Applying curve studies and the SEM Fig. 13, it is concluded that the addition of Nano-clay to composites leads to an increase in both of the strain and the core strength. Comparing the results of experimental and finite element modeling (FEM) data (in ABAQUS software) represented that there is a suitable compliance between them. Our results with the positional variation in core design can pave way in designing advanced engineered sandwich structures in aerospace, shipping, automotive industries. Therefore, these structures will have wide applications in the field of light structure, heat and fluid transfer, sound and vibration control. [ABSTRACT FROM AUTHOR]

In view of the serious problem of recycling and insolubility of thermosetting resin matrix composites in automobile manufacturing, a curing agent containing dynamic imine bond was synthesized by using biovanillin and 4, 4-diaminophenylsulfone. It was further used to cure epoxy resins into a vitreous matrix for fiberglass composite that could be reprocessed and recycled. The composite shows excellent mechanical properties, with a tensile strength and modulus of 670 MPa and 29 GPa, flexural strength and modulus of 752 MPa and 27 GPa, and shear strength of 55 MPa, which are comparable to the commercial battery pack composite material such as BAC 449. This new vitrimer-based composite has better mechanical properties, and its flame retardant can reach UL-94 V-0 level. In addition, owing to the nature of dynamic imine bonds, this vitrimer-based composite can be chemically degraded so that the fiber and resin in the composite can be recycled and reused, helping with carbon reduction and environmental protection. It has potential application in the manufacturing of composite covers of battery packs for electric vehicles. [ABSTRACT FROM AUTHOR]

This research aims to develop fiber-reinforced composites (FRC) with enhanced fire resistance, which can be particularly useful for the transport industry (e.g., aviation, automotive, and train production). The fire retardation was achieved through epoxy matrix modification with hexachlorocyclotriphosphazene (HCTP). First, the fire-resistant and mechanical properties of the epoxy matrix filled with different HCTP contents (4.8, 7.2, and 9.5 wt.%) were studied to select the most effective HCTP content for the impregnation of FRC. Then, glass, basalt, and carbon fiber fabrics were impregnated with epoxy filled with 7.2 wt.% of HCTP, and the fire resistance, flexural, and interlaminar fracture properties were studied to select the most effective HCTP-modified type of fiber reinforcement based on the test results. It was concluded that basalt fiber impregnated with epoxy filled with HCTP could be selected as the most effective reinforcement type, allowing excellent mechanical and flame-retardant properties. [ABSTRACT FROM AUTHOR]

The present work deals with analyzing the effect of silicon dioxide on mechanical and thermal stability of hybrid polymer composite. Compression molding is adopted to develop the hybrid composite with constant 0.5 wt.% of graphene and varying wt.% of silicon dioxide (2, 4 & 6 wt.%). Modified hummers method is used to synthesis graphene by chemical exfoliation of graphene from graphite flakes. Mechanical properties of developed composite is investigated using tensile, flexural, impact and interlaminar shear testing follow by fracture surface analysis of tested samples. Thermal stability is examined by thermogravimetric analysis and functional group confirmation is carried out using Fourier transform infrared spectroscopy (FTIR). Investigation over mechanical properties of fabricated composite reveals that addition of silicon dioxide up to 4 wt.% depicted higher flexural and tensile strength. Increment in silicon dioxide percentage improves the toughness of composite. FTIR results confirms the presence of asymmetric stretching vibrations due the after effect of hybrid fillers. Thermogravimetric analysis results depict that incorporation silicon dioxide increases the activation of energy of matrix from ~ 24.2 to 31.5 kJ/mol. [ABSTRACT FROM AUTHOR]

Composite materials are widely used in diverse areas of applications due to their high level of performance. They can be selected and engineered to provide a specific property. Many researches have been focused on studying bending and tensile characteristics of the composite reinforced by using fiber glass. This paper presents the fabrication process and evaluation study of both mechanical and physical properties characterization of fibre glass reinforcement epoxy resin. Unsaturated epoxy resin was reinforced using variable chopped E-glass fiber with loading of 0%, 5%, 15%, 40 wt% respectively to achieve this purpose. The specimens of the reinforced epoxy were prepared and investigated experimentally to access and evaluate their properties such as tensile strength, hardness and water absorption tests respectively. The test results showed that the specimen with added 40 wt% short fiber glass has highest values of ultimate tensile strength, Young modulus, hardness and the coefficient of the thermal conductivity compared with the other specimens but it has the demerit of higher water absorption percentage. Also, it was found that the specimen with 15 wt% has the lowest water absorption percentage. The obtained results suggest that the use of chopped E-glass fiber as reinforcement can enhance the properties of the epoxy matrix. [ABSTRACT FROM AUTHOR]

Flame retardants are often developed for epoxy resins and then transferred into their fiber-reinforced composites with uncertain results. Understanding this transfer in detail represents a critical scientific challenge. This study systematically compares epoxy resins with their glass-fiber reinforced composites, focusing on bisphenol A diglycidyl ether with the hardener dicyandiamide, the flame retardants melamine polyphosphate, ammonium polyphosphate, and silane ammonium polyphosphate, along with inorganic silicate. The research investigates changes in pyrolysis (thermogravimetry), flammability (UL 94, limiting oxygen index), and fire behavior (cone calorimeter) while also examining the flame-retardant modes of action and overall fire performance. The findings reveal that alterations in the amount of fuel, thermal properties, melt flow, and protective layer significantly impact ignition, flammability, and fire load, with a critical reduction in carbonaceous char within the composites preventing intumescence. This study quantifies the effects and provides a fundamental scientific understanding of the complex transfer process of flame retardants from resins to composites, offering essential insights that are of major importance for developing more effective flame-retardant materials.

This research investigates the influence of kevlar and glass fiber reinforcements on the mechanical and thermal properties of epoxy/vinyl ester (hybrid resin) composite. The hybrid resin was synthesized by achieving an interpenetrating network between epoxy and vinyl ester. The composites were characterized using tensile, flexural, impact, and thermo‐gravimetric analysis (TGA). Scanning electron microscopy was employed to analyze surface morphology whereas Fourier‐Transformation Infrared Spectroscopy (FT‐IR) was used to investigate the possible interaction between the constituents of the composites. The findings have shown a notable improvement in the mechanical properties after the hybridization of the resin. For reference, the tensile strength of glass/hybrid resin and kevlar/hybrid resin composites were observed to increase by 8.33% and 23.65%, as compared to glass/epoxy and kevlar epoxy composites respectively, whereas, the bending strength of these composites was improved by 8.36% and 30.61%, respectively. TGA also showed an enhanced thermal stability of the hybrid resin‐based composites. Such improvements are noticed due to multi‐resin incorporation (the oxirane group of epoxy reacts with the hydroxyl group of vinyl ester), confirmed by the FTIR, TGA, and morphological analysis. This study signifies that the proposed hybrid composites are better in terms of strength and modulus relative to conventional metallic materials. Highlights: The paper presents the development of novel hybrid resin, reinforced with synthetic fibers.Hybrid resin is imparted positively and is highly favorable in improving the mechanical properties of composites.The tensile strength of novel composites is increased by 8.33% and 23.65% relative to their base specimens, and a similar trend is observed in flexural and impact analysis.Fractured analysis showed that composite laminates deteriorated more intensely due to cohesive matrix fracture; adhesion failure was not observed at all, as evidenced by the emergence of micro‐cracks in resin.Developed novel composites exhibited maximum thermal stability; residual char in glass/epoxy/vinyl‐ester composite attained 17.81% higher, whereas kevlar/epoxy/vinyl‐ester achieved 3.56% relative to glass/epoxy and kevlar/epoxy base samples. [ABSTRACT FROM AUTHOR]

This study focused on the wear behavior of unidirectional, thick GF epoxy composites produced using the autoclave method. The thermal aging process was applied for 250 and 500 cycles to understand the wear behavior of the material as it ages over time. To evaluate the wear behavior of the samples, wear tests were carried out under three different loads (10, 20, and 30 N) and three different sliding distances (150, 300, and 450 m). Taguchi‐based regression analysis was used to analyze the experimental results. The results obtained were evaluated using ANOVA tables and main and contour graphs. When the test results are examined, it is surprisingly observed that the wear resistance of the composite material increases positively with the aging effect. With thermally aging while the coefficient of friction value of composite samples increases from approximately 0.12 to 0.3, the wear volume decreases from approximately 4 to 1.3 mm3. Taguchi based regression analysis showed that the relationship between wear and thermal cycle sliding distance and load can be established by reducing the number of experiments in wear studies. Highlights: Thermal aging effect on wear properties of thick GFRP was determined.Minimum wear volume and COF values were determined by applying ANOVA.It was determined that a load increment has the most impact on wear volume.Worn surface images supported the reduction in the wear rates of the thick GFRP.Empirical regression models developed for the mathematical prediction. [ABSTRACT FROM AUTHOR]

This study aims to synthesize TiC + TiB2 reinforced epoxy/glass fiber composites to enhance mechanical properties and resistance to wear and erosion. For this purpose, TiC + TiB2 particles were added to the epoxy matrix in contents of 0, 2.5, 5, 12.5, and 20 wt.%, and the composites were then created through the hand-layout technique. The mechanical, wear, and erosion properties were eventually analyzed. The wear mechanisms of samples were evaluated by scanning electron microscope (SEM) images. The findings indicated that adding 2.5 wt. % of particles maximized the modulus, increasing the tensile and flexural modulus rates by 26 and 17%, respectively. The hardness also improved when TiC + TiB2 particles were added. In fact, it reached the maximum level (58%) once 12.5 wt.% of particles were added. The wear resistance of the composites increased with the TiC + TiB2 content where adding 20 wt.% of the particles enhanced the abrasion resistance by 86% while lowering the friction coefficient. The erosion resistance was analyzed with a rotating device in an abrasive slurry under different variables such as rotation speed, impact angle, and sand rate. The maximum erosion resistance was observed in a composite sample containing 12.5 wt.% of TiC + TiB2 particles. [ABSTRACT FROM AUTHOR]

In recent years, the growing environmental awareness has prompted increased attention towards the substitution of nonrecyclable thermosetting epoxy resin composite materials with recyclable thermoplastic composite materials. The objective of this study is to utilize a laboratory‐made polymethyl methacrylate (PMMA)/methyl methacrylate (MMA) binary liquid resin (PMBLR) to prepare thermoplastic resin/glass fiber (GF) composite materials using the vacuum‐assisted perfusion method. These composites are then compared with GF‐reinforced thermosetting epoxy resin composites. The investigation reveals a significant influence of benzoyl peroxide (BPO) content on the mechanical properties of pure MMA and PMBLR casting resins, which also incorporate N‐methyl‐N‐((1‐methyl‐1H‐indol‐3‐yl) methyl) aniline (DMA) as redox composite initiators. The optimal mechanical properties for both types of casting resins are achieved at a DMA:BPO:MMA ratio of 0.5:1.2:100. Additionally, at a PMMA concentration of 24 wt% in PMBLR under this specific initiator ratio, the composites demonstrate the most desirable properties. Furthermore, a comparative analysis of PMBLR/GF composites and epoxy/GF composites indicates that the former exhibit superior 90° tensile strength, bending strength, and short beam shear strength. The fracture morphology analysis highlights discernible micro‐ductile fracture characteristics in PMBLR/GF composites, distinguishing them from epoxy/GF composites. Dynamic thermomechanical analysis (DMA) results further reveal a higher storage modulus and loss factor in PMBLR/GF composites when compared to epoxy/GF composites. Highlights: Glass fiber‐reinforced composites were fabricated at ambient temperature.A degradable PMMA/MMA binary thermoplastic resin (PMBLR) was developed as a replacement for non‐degradable epoxy.PMBLR composites exhibit enhanced strength compared to epoxy: tensile (+18.8%), bending (+27.4%), and short beam shear (+34.3%). [ABSTRACT FROM AUTHOR]

On-site construction projects typically employ staggered fastener patterns. This article describes the application of Hollo Bolts (HB). It also highlights the effectiveness of using flexible epoxy adhesive to increase the load-carrying capacity of staggered connections fastened with HB. The distribution of loads between connecting elements largely determines joint performance. Pultruded glass fiber reinforced polymer (PGFRP), bolted (B), and hybrid bolted/bonded (BB) double lap joints were subjected to a typical pulling load and numerically validated in this investigation. To simulate delamination effects, a Cohesive Zone Model with a 3D progressive damage analysis was developed. In addition, a parametric study capturing the influence of various geometrical variables such as e/d, overlap length, bolt size, adherend thickness, and the number of bolts was used to compare both categories of joints in detail. The results indicate that for staggered connections fastened with HB, an efficient load transfer can be obtained in conjunction with flexible epoxy adhesive. It is anticipated that this interaction will be even more effective as the overlap length, adherend thickness, and fastener diameter increase. The present study proves that BB connections are 43.56% stronger than B connections. [ABSTRACT FROM AUTHOR]

Background and purpose: This study was conducted with the aim of investigating parallel strand lumber (PSL) made from reed residue and laminated veneer lumber (LVL) obtained from poplar wood reinforced with glass fiber reinforced polymer (FRP) using epoxy resin. Materials and methods: The independent variable was FRP reinforcement for either LVL or PSL and control sample either LVL or LSL without FRP. The mechanical properties of the manufactured boards including bending strength (MOR) and modulus of elasticity (MOE) in the width and edge of the test sample, shear strength, compression strength parallel to the grain, internal bonding and screw withdrawal strengths were investigated as dependent variables. The obtained results were analyzed using completely randomized design and SPSS software. Results: Results showed that for all studied mechanical properties, the use of FRP increased the strength the PSL and LVL panels. For LVL, the effect of strengthening the samples with FRP was significant at the level of 1% and also for the modulus of rupture of the width and edge samples showed an increase of 93% and 59%, respectively. The value of MOE for samples reinforced with FRP showed an increase of 89.6 and 132% for the width and length of the PSL samples, respectively. For LVL, the MOE value of the width and edge of the samples increased by 54 and 95.5% with reinforcement. Reinforced PSL samples have improved shear strength by 31%, while this value was only 2.5% for LVL. In case of internal bonding, reinforcement with FRP improved the internal bonding strength of the samples by 92%. Screw withdrawal strengths improved by 27% due to the strengthening of the test samples by FRP. Conclusion: According to the results, it can be stated that the use of glass fibers and epoxy resin has a significant positive effect on the mechanical strength of PSL made of reed and LVL and it is possible to use low quality raw materials such as reed and low quality poplar wood layers. [ABSTRACT FROM AUTHOR]

The main objective of the research is developed toward adsorption electronic devices (Interface material) with the performance examined by the physical, mechanical, and thermal properties of the E‐glass fiber reinforced with the epoxy composite and particulate dispersed into the matrix in partial fulfillment of tiny amount of aluminum powder particles and MWCNT. Composite membranes with 15 wt.% E‐glass fiber and 2 wt.%, 4 wt.%, and 6 wt.% fine aluminum powder particle concentrations were partially filled with 0 wt.%, 0.5 wt.%, and 1.0 wt.% MWCNTs. Vacuum lay‐up technique is used to create the better adhesive hybrid composite, which is then assessed of the characteristics of the materials. The maximum thermal conductivity of EAEM2 (E‐Epoxy, A‐Aluminum particle, E‐E‐glass fiber, M‐MWCNT) is 0.3057 W/mK. The tensile, bending, and impact strengths of EAEM1 composites are higher than those of EAEM2 and EAEM3 (average values of EAEM1 composites: 86 MPa, 123.33 MPa, and 90.66 J/m2). However, the Shore‐D hardness of EAEM3 is 95.33. The test findings demonstrate a significant improvement in thermal properties with minimal marginal decrements in mechanical capabilities when carbon allotropes are increased. The composite system's morphology (EAEM3) demonstrates a clustered distribution of aluminum powder particles in the matrix. [ABSTRACT FROM AUTHOR]

The object of research is modified epoxy composite materials containing fibrous fillers treated in physical fields. The technological features of the development of tribotechnical epoxy composites, which must withstand the effects of elevated temperatures, have been considered. In this case, it is necessary to modify the structure of the epoxy polymer matrix, which is achieved as a result of the introduction of heat-resistant organosilicon varnish. Organosilicon varnishes and chopped fibers contain technological additives, which complicates the process of structuring epoxy composites and leads to the appearance of structural defects. Removal of technological additives and cleaning the surface of the aramid and glass fibers from lubricants is possible as a result of processing the components of the composition in physical fields. There is a need to study the influence of physical fields on the structuring processes of the epoxy system and the formation of the structure of epoxy composites with specified properties. Modified epoxy composites contain chopped aramid and glass fibers treated with ultrasound. The tribotechnical characteristics of epoxy composites were studied at a sliding speed of V=1.0 m/s with a change in specific load from 0.5 MPa to 1.5 MPa. The temperature in the tribocontact zone during frictional interaction rises to 100 °C with an increase in the specific load. An increase in the density of the surface layer of tribocontact of epoxy composites with fillers treated in physical fields was revealed. The practical recommendations have been compiled for the implementation of the treatment technology of components in physical fields, which ensures structuring of epoxy composites with high tribotechnical characteristics. [ABSTRACT FROM AUTHOR]

This study explores the application of abrasive waterjet drilling (AWJD) for varied patterns of GF/Al mesh hybrid composites (neat glass NG, AG: Al in the exterior surface, and GA: Al in the center). Key parameters such as jet pressure (P), standoff distance (S), and traverse speed (V) are systematically varied, influencing material removal rate (MRR), hole taper ratio (Tr), and roundness error (Re). Employing a Taguchi approach with an L9 design. It was indicated that the optimal conditions for maximum MRR are (P: 150 MPa, S: 2 mm, and V: 900 mm/min). V and S are the main influential parameters on Tr and Re. Gray relational analysis (GRA) is employed for simultaneous optimization, enhancing drilling performance. The optimal parameters P of 150 MPa, S of 2 mm, and V of 300 mm/min are determined. Validation trials confirm the effectiveness of the determined parameters. A robust multiple regression equation is formulated, providing a predictive model that aligns closely with experimental observations. Highlights: The hybrid composites were drilled via a nontraditional process.The attributes of the hole geometry and the material removal impacts were studied.Operation parameters were optimized to improve MRR, Re, and Tr.A multiple regression model and a confirmation test were performed and validated. [ABSTRACT FROM AUTHOR]

To simultaneously endow thermal conductivity, high glass transition temperature (Tg) and healing capability to glass fiber/epoxy (GFREP) composite, dynamic crosslinked epoxy resin bearing reversible β-hydroxyl ester bonds was reinforced with boron nitride nanosheets modified glass fiber cloth (GFC@BNNSs). The in-plane heat conduction paths were constructed by electrostatic self-assembly of polyacrylic acid treated GFC and polyethyleneimine decorated BNNSs. Then, the GFC@BNNSs were impregnated with the mixture of lower concentration (3-glycidyloxypropyl) trimethoxysilane grafted BN micron sheets, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate and hexahydro-4-methylphthalic anhydride, which accounted for establishing the through-plane heat transport pathways and avoiding serious deterioration of mechanical performances. The resultant GFREP composite containing less boron nitride particles (17.6 wt%) exhibited superior in-plane (3.29 W·m−1·K−1) and through-plane (1.16 W·m−1·K−1) thermal conductivities, as well as high Tg of 204 °C (Tg of the unfilled epoxy=177 °C). The reversible transesterification reaction enabled closure of interlaminar cracks within the composite, achieving decent healing efficiencies estimated by means of tensile strength (71.2%), electrical breakdown strength (83.6%) and thermal conductivity (69.1%). The present work overcame the disadvantages of conventional thermally conductive composites, and provided an efficient approach to prolong the life span of thermally conductive GFREP laminate for high-temperature resistant integrated circuit application. [ABSTRACT FROM AUTHOR]

The current work investigates the effects of drilling parameters on hole quality, including delamination and circularity, produced in hybrid composite materials consisting of neat glass fibre (NG) and hybrid glass fibre/Al-wire mesh in two distinct sequences, the first one being with Al-mesh in the outermost layers (AG) and the other with Al-mesh in the central layer (GA). The operation's process parameters are feed rate (F = 20, 40, and 60 mm/min), spindle speed (N = 1000, 2000, and 3000 rpm), and drill point angle (Ɵ = 90°, 120°, and 135°). Taguchi's L9 orthogonal array is used for the study. The optimal levels and effects of the process parameters were determined. Gray relational analysis (GRA) was employed to examine the complicated interactions influencing the results and ANOVA was used to evaluate the influence of process parameters. The results indicated that for all specimens, push-out delamination was more severe than peel-up. Circularity is minimized by using N = 3000 rpm, F = 20 mm/min, and Ɵ = 90°. At speed (N) of 3000 rpm circularity reduces by 83.5% and 76.5% compared to 1000 or 2000 rpm, respectively. Compared to other specimens, AG-specimen produced minimal delamination and circularity by an average of 6% and17.38%. The results of the confirmation test and regression model provide good agreement between the experimental and predicted results. [ABSTRACT FROM AUTHOR]

Three‐dimensional woven spacer composites (3DWSCs) with lightweight and excellent mechanical properties have promising application in communication, transportation, aerospace and other fields. However, traditional single‐layer 3DWSCs exhibit insufficient strength, especially when dealing with high thickness, as the pile yarns tend to buckle. In this study, inspired by the structural features of the Thalia dealbata, 3D woven integrated double‐layer glass fiber/epoxy resin spacer composites by mimicking were fabricated. Innovative integrated double‐layer structure design effectively improves the performance and failure mode of 3DWSCs under bending loads. Compared to single‐layer 3DWSCs, the resulting double‐layer 3DWSCs exhibited a 41.79% increase in peak bending load, a 46.85% increase in bending stiffness, and a 99.38% increase in energy absorption. In addition, the double‐layer 3DWSCs showed a low density of 0.52–0.55 g/cm3. This work introduces bioinspired double‐layer 3DWSCs with characteristics of lightweight and superior bending performance, potentially offering novel ideas for the design of high‐performance composites. Highlights: Inspired by the structural features of the Thalia dealbata, a 3D integrated woven double‐layer glass fiber/epoxy resin spacer composites by mimicking were fabricated.3D woven double‐layer spacer composites are lightweight (0.52–0.55 g/cm3) and can effectively improve the bending properties of single‐layer structures.Based on the analysis of the fracture morphology, the significant improvement of the fracture pattern of the single‐layer structure by the double‐layer structure is effectively demonstrated.This study introduces novel design strategies for multi‐layer lightweight composite materials and holds broad applications. [ABSTRACT FROM AUTHOR]

Interfacial characteristics of nanocomposites are critical limiting factors in the design of polymer nanocomposites. The nanocomposites have complex structures and play a pivotal role in controlling functional properties. Analysis of interfacial layers in polymer nanocomposites, existing between the polymer matrix and the nanoparticles plays a major role in determining their characteristics. High-frequency analysis of electrical conductivity and dielectric properties of carbon nanofillers which are embedded in an epoxy matrix were analysed using alternating current dielectric spectra. This article provides a correlation between the electrical transport properties and dielectric behaviour of epoxy carbon nanocomposites at different temperatures are investigated with variations in frequency. Electrical transport properties of nanocomposites are primarily dictated by electron tunnelling and matrix, nanofillers conductivity. Dielectric spectroscopy in the frequency range 10 Hz–8 MHz has been performed on epoxy nanocomposites with and without hybrid carbon nanofillers at one weight percentage (2:3 ratio). Dominant dielectric relaxation mode is observed in the base composite at a low-frequency region (≥10 Hz), whereas nanocomposite with hybrid carbon nanofillers is observed to induce two dielectric relaxations in the kHz region. Increase in non-monotonic variations in dielectric spectra makes the nanocomposite suitable for high temperature low sag conductor core, aerospace and cryogenic engineering applications. [ABSTRACT FROM AUTHOR]

This paper presents a study regarding the obtaining, characterizing and mechanically testing a new laminar composite material, consisting of epoxy resin reinforced with basalt plain fabric. The composites were obtained by manual lay-up, cross-link stage being developed by pressure molding in a hydraulic press. Rectangular plates were obtained and cut into samples with specific shapes, for the mechanical tests (tensile, three-point bending and compression). After testing, the fracture zone was analyzed using optical microscopy to observe the behavior of the composite following the mechanical stresses applied (fracture mechanism, voids presence and fiber delamination identification). Due to the low costs and non-hazardous nature, basalt fibers can be a serious competitor in the production of laminar composites that could successfully replace ordinary glass fiber composites. The mechanical properties in tensile, three-point bending, and compression of epoxy-resin-impregnated basalt fiber composites are comparable and even exceed those of widely used epoxy-resin-impregnated fiberglass composites. [ABSTRACT FROM AUTHOR]

This study investigates the impact of marble powder as a part of fine aggregate and the addition of glass fiber on the bond strength of concrete and deformed high-strength post-installed steel rebars using the epoxy chemical as an adhesive. Five marble dust powder (MDP) substitution percentages (i.e. 0%, 10%, 20%, 30%, and 35%) and the addition of glass fiber (i.e. 0.5%, 1%, and 1.5%) were used. The performance of deformed high-strength post-installed rebars in conventional concrete and concrete modified with 35% marble powder and 1% glass fiber was examined here utilizing pull-out tests on a total of 96 specimens. To examine the bond behaviors of deformed high-strength post-installed rebars at the epoxy–conventional concrete interface and epoxy-modified concrete with MDP and glass fiber interface, test criteria included concrete compressive strength, anchorage depth of rebar into concrete, rebar diameter, and concrete cover to rebar diameter ratio. For post-installed high-strength deformed rebar, bond stress–slip relationships were determined, examined, and subsequently compared with prior work and readily available codes. It was found that none of the specimens exhibited pull-out failure and that the majority of them displayed concrete splitting, concrete rapture, or rebar rapture failure. This suggests that epoxy resins are particularly successful as bonding agents to retrofit concrete structures at the steel–concrete contact. A closed-form equation for predicting the bond strength for post-installed high-strength deformed rebar was also created using regression analyses on the experimental data. With a significant coefficient of determination (R2 = 0.85) the observed predicted bond strengths and the test data were quite similar. [ABSTRACT FROM AUTHOR]

Frontal polymerization (FP) is a self-sustaining reaction that relies on polymerization exothermicity and heat transfer. This study explores the inplane and in-depth FP mechanisms of continuous fiber-reinforced epoxy composites. First, the effects of initiator and diluent concentrations on the FP behaviors of neat epoxy resins were examined. It was found that the frontal velocity and frontal temperature of the neat resins increase with an increase of either the initiator concentration or the diluent content, depending on the polymerization enthalpy and curing kinetics. Then, the FP behaviors of continuous carbon fiber and glass fiber-reinforced epoxy woven composites were investigated. The results showed that the in-plane FP behavior of the composites was primarily controlled by the thermal conductivity and specific heat capacity of the continuous fibers, whereas the in-depth FP behavior mainly depended on the pores of the woven fabrics. Highlights • Frontal velocity and temperature of neat resins are controlled by the polymerization enthalpy and curing kinetics. • The in-plane FP behavior of continuous fiber reinforced composites is dependent on the thermal conductivity and specific heat capacity of the fibers. • The in-depth FP behavior of composite is determined by both the thermal conductivity of fibers and the pores of fabrics. [ABSTRACT FROM AUTHOR]

The pull-out method was used to study the adhesive strength τ of "fiber–thermoset" systems with wide variations in area. Studied binders were based on resins that had different chemical natures (epoxy, epoxy phenol, orthophthalic, polyphenylsiloxane, and phenol–formaldehyde). Shear adhesive strength was determined for systems with two fiber types (glass and steel fibers). It was shown that strength τ depended on scale (area). Formation of τ occurred during the curing process and the system's subsequent cooling to the measurement temperature T. It was found that interface strength depended on measurement temperature across a wide temperature range that covered the highly elastic and the glassy state of the adhesive. The influence of residual stresses τres, acting at the "binder–fiber" interface, on the nature of the curves describing the dependence of the adhesive strength on the studied factor was experimentally shown. A qualitative explanation of the observed regularities is proposed. [ABSTRACT FROM AUTHOR]

The surface treatment of chopped glass fiber (GF) can significantly improve the strength, impact resistance, and durability of epoxy resin (EP), and the homogeneity of GF modified EP material is better than that of continuous fiber reinforced EP, which has an important application in the engineering field. The effects of surface treatment and addition of chopped GF on the rheological behavior and mechanical properties of EP/modified chopped GF composites were studied by alcohol washing, coupling agent treatment, and acid etching modification methods. In addition, a reactive flame retardant containing phosphorus, nitrogen and bromine was synthesized, and the flame retardant application was studied in the EP/modified chopped GF system. The results show that the surface micromorphology of the chopped GF treated with acid etching is relatively rough, which can greatly increase the initial shear viscosity of the system, and the mechanical properties of the cured composites are significantly better than those of the GF treated with alcohol treatment and coupling agent. The chopped GF content of acid etching treatment is 2.0%, and the tensile strength of the composite is the highest, which is 59.75 MPa. When the flame retardant content is 10%, the peak heat release rate and total heat release of the composite are significantly lower than those of pure EP, and the mechanical properties are improved at the same time. [ABSTRACT FROM AUTHOR]

In this study, we compare the effect of various precursor‐based graphene oxide (GO) nanofillers on enhancing the mechanical performance of E‐glass fiber‐reinforced epoxy resin composites (EGFPs). GO derived from bituminous coal (BC‐GO) and graphite (Gr‐GO) were dispersed into an epoxy resin matrix. The resulting mixture was combined with E‐glass fiber mats using vacuum‐assisted resin infusion molding. Notable improvements (38.9% in flexural strength, 22.9% in tensile strength, and 21.6% in impact strength) were observed in BC‐GO‐reinforced EGFPs at 0.25 phr loading of BC‐GO. The improvements for Gr‐GO‐reinforced EGFPs were 28%, 9.3%, and 6.8%, respectively. XRD analysis of BC‐GO showed a diffraction peak at 2θ = 20.9°. Except for this peak, no other crystalline peaks were observed when BC‐GO was incorporated into EGFPs. FTIR spectra of both composite samples, with or without the nanofiller, were similar due to the spectral peaks overlap. TEM demonstrated the exfoliated morphology of BC‐GO in EGFPs. These findings underscore the potential of BC‐GO as a cost‐effective reinforcement for polymer nanocomposites across various industrial applications, including the development of lightweight and strong materials for aerospace and automotive industries, protective coatings, petroleum, and aerospace production systems. Highlights: BC‐GO demonstrates superior mechanical performance compared to Gr‐GO in EGFPs.0.25 phr BC‐GO improves 38.9% flexural, 22.9% tensile, and 21.6% impact strengths.Beyond 0.25 phr, BC‐GO and Gr‐GO showed a decline in mechanical enhancement.Role of particle size, loading & adhesion to matrix analyzed using XRD, FTIR, and DLS.Coal‐GO is an attractive alternative nanofiller for EGFPs. [ABSTRACT FROM AUTHOR]

Composite materials made up of polymer matrix reinforced with synthetic fibers have gained popularity of late owing to their enhanced mechanical properties. However, very little work is reported to date on metals being used as filler material. Research gaps were obtained pertaining to the use of metallic fillers in synthetic fiber reinforced polymer composites. This paper demonstrates an attempt to fabricate composites made of Epoxy polymer matrix and E-glass fiber reinforcement with Mild Steel in its powdered form as fillers. Composites are prepared in varying weight percentages of the filler in the order of 2 wt. %, 4 wt. % and 6 wt. %. Hand layup method is employed for fabricating these composites which are later subjected to compression. Further, the samples are machined according to ASTM D3039 standard for tensile test and ASTM D256 standard for Izod impact test. Hardness test is also performed using a Shore D Durometer and these properties are compared with the unfilled samples. The results indicated that the weight percentage of the filler clearly influenced the mechanical properties of the developed composites. This study also revealed that the hardness and tensile strength of these composites improved with the incorporation of fillers up to 2 wt. % whereas, the impact strength improved up to 4 wt. %. Thereafter, there was a decline in their impact and tensile properties. However, hardness marginally increased beyond 4 wt. %. This area is open for research with regard to their usability under tribological, high temperature or magnetic conditions. [ABSTRACT FROM AUTHOR]

Fiber-reinforced polymer composites are manufactured using various methods, with vacuum-assisted resin transfer molding (VARTM or VARIM). This study's primary focus lies in assessing how the orientation of sampling impacts the mechanical properties of glass fiber-reinforced pure and nanocomposites. 2 wt.% nano Al2O3- doped and non-doped composites were produced using the VARTM process. Tensile, flexural, and density test specimens were extracted from three distinct zones and two distinc direction those aligned horizontally to the resin flow (HRF) and those oriented vertically to the resin flow (VRF). Remarkably, results showed up to a 3.91% increase in values from samples in the third zone, particularly on the vacuum outlet side. To facilitate precise stress value comparisons across plates, uniform sample orientation and consistent zone selection are essential. [ABSTRACT FROM AUTHOR]

Glass fibers (GFs) are frequently employed as reinforcement fibers for polymer resins such as epoxy and polyester. The mechanical behaviors of GFs polymer composites are nevertheless constrained by weak interfacial adhesion between polymer matrix and GFs. Herein, we invented a cross‐linking modified sizing agent using polyethyleneimine and bisphenol A epoxy emulsion, and studied the effect of cross‐linking extent on GF surface characteristics and GF/epoxy interfacial adhesion. The treatment of GFs with cross‐linking modified sizing agent facilitated the formation of interpenetrating polymer networks in composites for strengthening interface interaction. The results show that the modified GFs have a rough surface and improved interfacial adhesion with epoxy matrix. When sizing agents with cross‐linking extent of the 23.0%, the GF/epoxy composites show advanced interfacial shear strength (IFSS) and transverse fiber bundle tension (TFBT) strength. This work demonstrates that the cross‐linking extent of sizing agent could regulate interfacial adhesion, which is a facile and promising strategy in reinforcing glass fiber polymer composites. Highlights: Crosslink the sizing agent to enhance GF mechanical properties was reported.GF surface energy was enhanced and thickness of GF/epoxy interphase increased.IFSS and TFBT strength of the GF/resin composites increased by 23.65% and 30.54%, respectively. [ABSTRACT FROM AUTHOR]

Although epoxy resin has been extensively used in the field of wind turbine blades, polyurethane has attracted much attention in recent years, due to its potential value of better fatigue resistance, lower processing viscosity and higher strength than epoxy resin blades. Herein, we construct a dense cross-linking structure in polyurethane (PU) based on different amounts of hydroxypropyl methacrylate (HPMA) with low processing viscosity and excellent mechanical properties. By increasing the content of HPMA, the thermal stability of PU is enhanced, but the micro-morphology does not change significantly. When the content of HPMA is 50 g (in 200 g copolymer), the PU sample PH-50 exhibits a viscosity of 70 MPa·s and a gelation time of 120 min at 25 °C, which is sufficient to complete processes like pouring and filling. By post-curing the PH-50 at 80 °C for 2 h, the heat distortion temperature can reach 72 °C, indicating the increase of temperature resistance. The PU copolymers also have excellent mechanical and dynamic thermo-mechanical properties due to the cross-linking structure between PU chains and poly-HPMA chains. Additionally, the PU copolymer has excellent compatibility with various glass fiber fabrics (GFF), showing a good match in the vacuum infusion experiment and great properties in the mechanical test. By compounding PH-50 with GFF, the composite with high strength is easily prepared for a wind turbine blade in various positions. The tensile strengths of the composites are all over 1000 MPa in the 0° direction. Such composites are promising for the future development of wind turbine blades that meet the stringent requirements for outstanding processing and mechanical properties. [ABSTRACT FROM AUTHOR]

Glass fiber‐reinforced polymer‐matrix (GFRP) composites are used to manufacture devices such as radomes, electrical insulators, and radar‐absorbing structures, many of which are used in applications with strict mechanical and dielectric property requirements. As such, designs and properties of GFRP composite materials should be regularly improved to guarantee their safe operation and meet their constantly evolving application requirements. In this study, glass fiber (GF) particles and epoxy resin 128 (EP‐128) were used to manufacture high‐performance EP/GF‐X composites with GF particle contents ranging from 5% to 40%. An investigation into their mechanical and dielectric properties revealed that EP/GF‐20 composite specimens presented the best mechanical performance with their bending strength and modulus reaching 159.68 MPa and 6521.92 MPa, respectively, and an average dielectric constant of 4.862 within the 10–105 Hz frequency range. A theoretical analysis of the EP/GF‐X composite specimens' dielectric constants using classic dielectric models based on the Lichtenecker, Bruggeman, Jaysundere‐Smith, and Maxwell‐Garnett rule‐of‐mixture equations indicated that the dielectric model based on the Bruggeman rule‐of‐mixture equation provided the dielectric constants closest to the measured values with a maximum deviation of less than −0.321% for EP/GF‐40 composites. This study provides a feasible strategy to control the mechanical and dielectric properties of GFRP composites. Highlights: Glass fiber (GF) particles and epoxy 128 (EP‐128) resin were used to manufacture high‐performance glass fiber‐reinforced epoxy (EP/GF‐X) composites.The composite manufacturing process was carefully controlled to ensure uniform distribution and orientation of GF particles in the EP‐128 resin.The mechanical and dielectric properties of the manufactured EP/GF‐X composites were effectively tailored by controlling the content and distribution of GF particles in the EP‐128 resin matrix.The dielectric constants of the EP/GF‐X composites were measured experimentally and predicted using various theoretical dielectric models.The Bruggeman model provided the dielectric constants of the EP/GF‐X composites closest to the measured values. [ABSTRACT FROM AUTHOR]

Due to the high interest in the use of glass/epoxy laminates in aerospace applications, aviation, and as cryogenic tanks, it is crucial to understand the behavior of composites under challenging environmental conditions. Polymer composites are exposed to low temperatures, including cryogenic temperatures, which can lead to the initiation of microdamage. This paper investigates damage initiation/accumulation and its influence on the properties of cross-ply woven glass fiber epoxy composites at low temperatures compared to room temperature conditions. To evaluate the influence of a low-temperature environment on the mechanical performance of glass fiber reinforced epoxy composite (GFRP) laminates, three types of test campaigns were carried out: quasi-static tensile tests and stepwise increasing loading/unloading cyclic tensile tests at room temperature and in a low-temperature environment (−50 °C). We demonstrated that the initial stiffness of the laminates increased at low temperatures. On the other hand, there were no observed changes in the type or mechanism of developed damage in the two test conditions. However, the reduction in stiffness due to the accumulated damage was more significant for the laminates tested at low temperatures (~17% vs. ~11%). Exceptions were noted in a few formulations where the extent of damage at low temperatures was insignificant (<1%) compared to that at room temperature. Since some of the studied laminates exhibited a relatively minor decrease in stiffness (~2–3%), we can also conclude that the formulation of matrix material plays an important role in delaying the initiation and formation of damage. [ABSTRACT FROM AUTHOR]

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