Maximum Tensile Load Research Articles

Formation of the Interlock Morphology and Its Role in Refill Friction Stir Spot Welding of Aluminum Alloy to Steel

Considering energy conservation and emission reductions, lightweight automobiles have become a research focus in the automotive industry. Steel/aluminum joining is regarded as an ideal lightweight structure, which can not only reduce the energy consumption but also ensure safety and is already attracting extensive attention. In this study, aluminum alloy 6061 and B410LA steel sheets were successfully joined by refill friction stir spot welding. The tensile properties, microhardness distribution and interfacial microstructure characteristics of the steel/Al welded joints were investigated. The maximum tensile load of the steel/Al joint was 4.3 kN. The mechanical properties of the steel/Al refill friction stir spot welded joint were largely determined by the bonding quality of the sleeve-plunging zone. With the stirring of the sleeve and the pin during the refill friction stir spot welding, work hardening occurred in the stir zone (SZ). The microhardness of the SZ was significantly higher than that of the steel base metal (BM) and could be detected on the steel side. The Fe-Al intermetallic compound (IMC) layer was continuously distributed at the interface of the sleeve-plunging zone, revealing good uniformity in the thickness. In particular, a hook-and-vortex-like structure formed during the refill friction stir spot welding process in the sleeve-plunging zone, producing a mechanical interlock effect at the interface. The ideal mechanical properties of the welded joint could be attributed to the good quality of the metallurgical and mechanical bonding at the interface, especially the mechanical interlock effect, thereby depending on the hook-and-vortex-like structure.

A novel dissimilar resistance spot welding of Ti6Al4V alloy and 316L stainless steel via copper as interlayer by using optimal electrodes

A novel dissimilar resistance spot welding of Ti6Al4V alloy and 316L stainless steel was performed via copper as interlayer by using optimal electrodes. A significant improvement in nugget morphology being of less defects was achieved with increasing the copper interlayer thickness from 50 μm to 400 μm. Thinner interfacial reaction layers at both the nugget/titanium interface and the nugget/stainless steel interface and finer equiaxed dendritic grained structure at the inner nugget were formed with copper interlayer thickness of 300 μm compared with those without interlayer. The formation of TiCu and Ti2Cu was facilitated with the incorporation of Cu into the nugget, which effectively inhibited the formation of the brittle Ti–Fe intermetallic compounds including Fe2Ti. The nugget in the welded joint with copper interlayer in 300 μm thickness exhibited a far lower microhardness than that of the interlayer-free welded joint, and the average microhardness reduced to 604 HV in the inner nugget, which was about 36% lower than that of the interlayer-free welded joint. The tensile shear load of the welded joint exhibited an increased tendency with increasing interlayer thicknesses from 50 μm to 300 μm, and the maximum tensile shear load of 6.3 kN was obtained with the interlayer thickness of 300 μm, which was ∼97% higher than that of the interlayer-free welded joint. The welded joint with copper interlayer exhibited hybrid ductile and fragile fractured characteristics. The work would provide a facile and cost-effective method to achieve a reliable welded joint of Ti alloy and stainless steel.

Hydrogen Embrittlement Behavior of API X70 Linepipe Steel under Ex Situ and In Situ Hydrogen Charging.

This study investigates the hydrogen embrittlement behavior of API X70 linepipe steel. The microstructure was primarily composed of a dislocation-rich bainitic microstructure and polygonal ferrite. Slow strain-rate tests (SSRTs) were performed under both ex situ and in situ electrochemical hydrogen charging conditions to examine the difference between hydrogen diffusion and trapping behaviors. The ex situ SSRTs showed almost the same tensile properties as air and a limited brittle fracture confined to near the surface. In contrast, the in situ SSRTs showed an abrupt failure after the maximum tensile load, leading to a brittle fracture across the entire fracture surface with stress-oriented hydrogen-induced cracking (SOHIC). The crack trace analysis results indicated that SOHIC propagation paths were influenced by localized hydrogen accumulation due to high-stress fields. As a result, the dominant hydrogen embrittlement mechanisms, such as hydrogen-enhanced localized plasticity (HELP) and hydrogen-enhanced decohesion (HEDE), changed. These findings provide critical insights into the microstructural factors affecting hydrogen embrittlement, which are essential for the design of hydrogen-resistant steels in hydrogen infrastructure applications.

Influence of different types of mouthwashes on force decay of elastomeric chain recommended in SARS-COV-2 pandemic.

This study aimed to compare the force decay of the power-chain elastics after exposure to anti-coronavirus 2019 (COVID-19) antiseptic mouthwashes at different intervals. A total of 300 power-chain pieces were used from American Orthodontics (AO) and Dentaurum (D) brands. Each piece composed of five loops that were selected to simulate canine retraction distally. The samples were randomly grouped according to immersion in the tested mouthwashes 0.2% povidone-iodine (PVP-I), 1% hydrogen peroxide (H2O2), and 0.2% chlorhexidine (CHX) and cetylpyridinium chloride (CPC). The maximum tensile load failure testing (MTLT) was assessed at six time points (zero, one hour, 24 hours, 1, 2 and 4 weeks). Analysis of variance (ANOVA) and Tukey's post hoc tests were used to analyse the data, where P < 0.05. Significant differences in MTLT of power-chain elastics used at different immersion intervals were observed. MTLT, in each tested group, decreased significantly as the immersion time increased with significant differences among the tested mouthwashes at each time point. H2O2 group displays a maximum force decay throughout the time intervals for both brands, in contrast to CPC group, which shows less degradation over time. Both brands are decade over time during exposure to the tested mouthwashes. CPC mouthwashes is a good option to be described for orthodontic patient during COVID-19 pandemic, whereas H2O2 mouthwashes should be avoided.

Interfacial microstructure and mechanical property of dissimilar resistance spot welded joint of TC4 titanium alloy and 316L stainless steel with nickel interlayer

Dissimilar materials of TC4 titanium alloy and 316L stainless steel were joined by means of resistance spot welding with nickel interlayer in different thicknesses. A significant enhancement in terms of nugget morphology quality with less defects was achieved for the welded joints with nickel interlayer compared with that without interlayer. With increasing the nickel interlayer thickness from 50 μm to 300 μm, the effective nugget diameter increased gradually from ∼4.8 mm to ∼5.2 mm, which was lower than that of the interlayer-free welded joint being ∼5.9 mm. A thinner intermetallic compound layer with dual-layered structure features with thickness of ∼11 μm was formed at the nugget/titanium interface in the welded joint with nickel interlayer compared with that of the interlayer-free welded joint, meanwhile an intermetallic compound layer with thickness of ∼3 μm was formed at the nugget/stainless steel interface, which exhibited serrated structure features. The introduction of nickel interlayer in the welded joint could suppress the formation of the brittle Ti–Fe intermetallics such as Fe2Ti, and facilitate the formation of TiNi, Ti2Ni and TiNi3. A more homogeneous current density distribution and a lower peak temperature (1809 °C) during welding were achieved via employing nickel interlayer. With increasing nickel interlayer thickness from 0 μm to 300 μm, the tensile shear load of welded joints experienced an increased tendency first and then decreased, meanwhile the maximum tensile shear load of 3.7 kN was obtained with the interlayer thickness of 200 μm, which was 61% higher than that of the interlayer-free welded joint.

Numerical investigations of GRS wall performance with tiered configurations

Geosynthetic Reinforced Soil (GRS) walls have become increasingly popular as a result of their numerous advantages. In some cases these structures are constructed in a multi-tiered configuration, which makes their behavior more complicated. Nevertheless, the response of the multi-tiered walls is insufficiently explained by the existing design manuals and literature studies. This paper investigated the performance of GRS walls with multi-tiered configurations using two-dimensional (2D) finite element numerical models. This study compares the performance of two-tiered GRS walls with simple GRS walls (single-tiered). It also examines the impact of offset distance, backfill strength properties, and reinforcement parameters (vertical spacing and reinforcement length) on horizontal deformations and reinforcement tensile loads in two-tiered GRS walls. Adopting a multi-tiered configuration for GRS walls can significantly reduce both the horizontal wall deformation and the maximum reinforcement tensile loads. Additionally, the critical offset distance found in this study is significantly smaller than that recommended by the Federal Highway Administration (FHWA) guidelines. The finite element results also demonstrate that using high-quality backfill soil can minimize interaction between lower and upper tiers. Using a uniform reinforcement length of 0.6H for both tiers significantly reduces horizontal deformation compared to the FHWA recommendation of 0.6H and 0.35H for the lower and the upper tier respectively.

An experimental study of cold-formed steel connections with screwed clip angle under tension and shear loads

This paper aims to investigate the performance of typical cold-formed steel (CFS) beam-to-beam connections between floor bearers and floor joists through a series of full-scale experiments. The investigated connections consisted of a lipped channel (floor joist), an unlipped channel (floor bearer), a thin-walled clip angle (connector), and a self-drilling screw (fastener). In this study, customised T-shaped and H-shaped CFS connection specimens were tested to examine the performance under tension and shear loads, respectively. Two sizes of self-drilling screws, 10 G and 14 G, were used with the selected load bearing clip angle. The fabricated connection specimens were subjected to displacement-controlled tension and shear loads. The experiments uncovered the ultimate connection strengths, load-displacement relationships, and failure mechanisms of the designed CFS connections under the applied loads. Moreover, the experimental tensile and shear strengths of the connections were compared with the strengths predicted by the standard design equations. It was found that the screw pullout on the anchored leg of the clip angle was the main mode of failure under the tensile load. On the other hand, two different failure modes—fracturing of 10 G screws or shear buckling of the cantilevered leg of the clip angle with 14 G screws—were observed in the H-shaped specimen under the applied shear load. Among the designed connection specimens, the maximum tensile load capacity was 30.86 kN and the maximum shear load capacity 88.15 kN. The standard design calculations predicted screw pullout failure under tension, while the shear bucking failure mode of the clip angle under shear load was overlooked.

Numerical Investigation of the Effect of Deltoid Radius on Tensile Load in T-joints

In this study, T-shaped joints were designed from composites with different deltoid radius. For this purpose, carbon fiber woven fabrics were preferred as reinforcement elements. Then, tensile analyzes were performed on these composite T-joints. The effect of the deltoid radius on the maximum tensile load and damage behavior of the structure was examined. As a result of the analyses, fiber tensile-compression damage images occurring in the structure for each deltoid radius were obtained along with the load-displacement graph. The Hashin damage criterion was preferred for damage onset. Material Property Degradation (MPDG) method was used for damage progression in progressive damage analysis. By increasing the deltoid radius from 6 mm to 12 mm, the maximum contact load increased by approximately 10%, and by increasing it to 18 mm, the maximum contact load increased by approximately 20.11%. Fiber compression damage, spread over a wide area on the lower surface of the flange where it does not come into contact with the web, was determined to be the dominant damage type, and it was determined that this damage decreased with the increase of the deltoid radius. it was observed that as the deltoid radius increases, the T-jointed composite structure exhibits more rigid material behavior.

A novel crimped composite spline joint for pultruded FRP tubes: Conceptual design and tensile properties

Creating an effective composite joint between fiber-reinforced polymers (FRPs) and metallic profiles poses a significant challenge for heavy-loaded and lightweight emergency truss bridges. A novel crimped composite spline joint (CCSJ) was developed to achieve satisfactory engineering performance. Comparative tensile tests were conducted to evaluate the tensile properties and load-carrying mechanism of the CCSJ in comparison to those of joints without splines. Finite element (FE) analysis considering the crimping process and tensile loading was simultaneously executed and calibrated by experiments. Parametric simulation was supplemented to explore the key factors influencing the ultimate bearing capacity. The results indicated that the novel CCSJ features a simple preparation process, high connection efficiency, and large bearing capacity. A 60×6 mm hybrid FRP tube can withstand a maximum tensile load of 804 kN, achieving a connection efficiency of 61.3 % without the need for any secondary processing of the FRP tube. The CCSJ demonstrates a significantly higher connection efficiency of approximately 20 % compared to joints without splines. The ability of the CCSJ to effectively transfer significant axial loads through the interfacial friction effect is attributed to the increase in the interfacial contact area and preloading radial pressure resulting from the incorporation of pre-crimping splines. A typical failure mode involves interfacial slippage, resulting in satisfactory ductile behavior. The ultimate bearing capacity of the CCSJ is positively correlated with the crimping variables, friction coefficient, spline length, and number of splines. The FE model demonstrates sufficient accuracy in predicting the key behavioral indicators of the composite joint.

Effect of ultrasonic amplitude and riveting speed on mechanical properties of Ti-45Nb riveted lap joints

Ultrasonic vibration-assisted machining has been introduced as a new process in riveting aircraft components. In this paper, the effects of different ultrasonic amplitudes and riveting speeds on the quality, shear properties, and cross-tension properties of riveted joints are investigated. The failure sample fracture was characterized using a scanning electron microscope and the cause of the fracture was discussed. The results show that the ultrasonic amplitude is negatively correlated with the height of the riveted joint and positively correlated with the diameter of the riveted joint. The maximum shear failure load was obtained at a riveting speed of 5 mm/s with an ultrasonic amplitude of 35.3 μm, and the maximum cross tensile failure load was obtained at an ultrasonic amplitude of 23.3 μm. All shear fractures occurred in the rivet shanks and all cross fractures occurred in the rivet manufactured head, and the failure modes of both shear and cross-tension fracture were mixed brittle and plastic fracture modes.

Comparative assessment of failure in single shear lap joints fabricated using various joining techniques

The current research endeavour reports the performance of single shear lap joints of flax/PP composite laminates. The joints were fabricated using mechanical joining, fusion bonding (ultrasonic and hot plate joining), and hybrid joining techniques (mechanical/ultrasonic joining and mechanical/hot plate joining). In case of the mechanical and hybrid joining, the effect of the bolt size, and number of bolts (single and double) on the tensile failure load was investigated. Pertaining to mechanical joining, the large bolt size and double bolts recorded higher tensile failure load compared to smaller bolt size and single bolt, respectively. Whereas with double bolts, no increase in the tensile failure load was observed for the hybrid joints, due to reduction in bonded area. The hybrid joints (mechanical/ultrasonic) recorded the maximum tensile failure load compared to all other type of joints. The load-extension behaviour and failure of joints was also examined. Expect mechanical joints, all other joints exhibited structural type of failure. In contrast, the mechanical joints resulted in a net-tension failure mode with failure line passing through the hole. However, the thermal decomposition and crystalline behaviour (XRD spectra) of developed joints did not vary significantly. The morphology of failed joints was examined using scanning electron microscope.

Extrinsic-Riveting Friction Stir Lap Welding of Al/Steel Dissimilar Materials.

To obtain high-quality joints of Al/steel dissimilar materials, a new extrinsic-riveting friction stir lap welding (ERFSLW) method was proposed combining the synthesis advantages of mechanical riveting and metallurgical bonding. SiC-reinforced Al matrix composite bars were placed in the prefabricated holes in Al sheets and steel sheets, arranged in a zigzag array. The bars were stirred and mixed with Al sheets under severe plastic deformation (SPD), forming composite rivets to strengthen the mechanical joining. SiC particles were uniformly dispersed in the lower part of the welding nugget zone (WNZ). The smooth transition between the SiC mixed zone and extrinsic-riveting zone (ERZ) ensured the metallurgical bonding. The maximum tensile shear load of the joints reached 7.8 kN and the maximum load of the weld per unit length was 497 N/mm. The fracture occurred at the interface between the rivets and steel sheets rather than the conventional Al/steel joining interface. Moreover, ERFSLW can prolong the service life of joints due to three fracture stages. This method can be further extended to the welding of other dissimilar materials that conform to the model of "soft/hard".

A Biomechanical Study of Calcaneal Tuberosity Avulsion Fracture: A Comparison Between Three-Screw Versus Two-Screw Fixation Strength.

A calcaneal tuberosity avulsion fracture constitutes a sub-group of calcaneal fractures and it poses a high risk of soft tissue compromise, necessitating urgent reduction and fixation. This fracture was commonly treated with screw fixation, andfixation failure associated with this method has been reported in the literature. In light of this, we tested and compared the strength oftwo-screw(2S) versus three-screw (3S) fixations, where the third screw was fixed from the posterior calcaneal tuberosity towards the anterior process in addition to the two parallel screws. Synthetic calcaneum models were tested with an Instron machine to measure the maximum tensile load and stiffness. The mean maximum tensile loads for 3S and 2S were 455.8 N (SD = 47.4) and 341.0 N (SD = 30.9), respectively, and the difference was statistically significant. The mean stiffnesses for 3S and 2S were 29.2 N/mm (SD = 1.8) and 29.7 N/mm (SD = 2.0), but this difference did not reach statistical significance. Based on our findings, the added third screw increased the pull-out strength and can be inserted percutaneously to minimize soft tissue compromise.

Experimental Study on the Identification and Diagnosis of Dynamic Crack Propagation in the Piston Rods of Process Gas Compressors in Underground Gas Storage

Ensuring the reliability of process gas compressors is critical for underground gas storage, as piston rod fractures can lead to serious accidents, such as natural gas leaks or explosions. On-time monitoring and early detection play a vital role in preventing catastrophic consequences, minimising costs, and reducing production losses due to unplanned downtime. This study presents a novel accelerated life-testing method designed to replicate the fracture events of reciprocating compressor piston rods. By accelerating the induced crack initiation and propagation to the final fracture, comprehensive analyses of the fracture results are performed to reveal the piston rod fracture mechanism and the resulting secondary damage to the unit. The research further presents an innovative approach for identifying piston rod crack propagation by means of acoustic emission. Through kinetic analysis and time–frequency domain analysis, the study elucidates two mechanisms responsible for triggering crack signals during the compressor operation: the contact impact between the crosshead pin and the bearing due to the piston rod load reversal, and crack propagation occurring before the maximum tensile load is reached. In addition, the study identifies the piston rod crack expansion signal frequency band and achieves a high-sensitivity identification of crack dynamic growth by extracting signal sub-band features associated with crack propagation. Then, a prediction model of the fatigue crack growth rate was established based on the AE energy release rate, which provides a quantitative assessment of dynamic crack propagation during compression. This method aims to provide a maintenance strategy for piston rod fractures, thereby increasing the operational safety of critical dynamic equipment in underground gas storage.

Joining thin galvanized low carbon steel sheet to AA6056-T4 by resistance spot welding and adhesive weld bounding

Multimaterial assemblies made by resistance spot welding (RSW) process offer a cost-efficient lightweight solution for automotive body-in-white production. However, joining different materials, such as steel (Fe) and aluminum (Al), brings issues due to their different physical properties and low weldability. The present work investigated the evolution of the weld between a thin galvanized low carbon steel sheet and an AA6056-T4 aluminum alloy from macroscopic observations to the evolution of the intermetallic compound layer (IMC) during RSW. Comparisons between homogeneous Al-Al RSW, Fe-Al RSW and Fe-Al adhesive weld bonding for different mechanical solicitations were also realized. Observations showed that the interface for short welding periods is composed of a thin and discontinuous IMC layer. The interface also presents defects that facilitate crack initiation and propagation, leading to an interfacial fracture mode. The different mechanical tests carried out demonstrated that the Al-Al and Fe-Al welds reached a similar maximum tensile load under the shear–tensile test. However, Fe-Al assemblies under cross-tensile test showed poor mechanical properties. The use of an adhesive layer with an Fe-Al spot weld seems to be a potential solution, as it is easily implementable on production lines and improves the mechanical properties of Fe-Al assemblies.

Characterization of an in vitro engineered ligament model

In vivo tendon and ligament research can be limited by the difficultly of obtaining tissue samples that can be biochemically analyzed. In this study, we characterize the most widely used in vitro engineered ligament model. Despite previous works suggesting multiple passages change gene expression in 2D primary tenocytes, we found no relationship between passage number and expression of classical tendon fibroblast markers across different biological donors. When engineered into 3D ligaments, there was an increase in maximal tensile load between 7 and 14 days in culture, that corresponded with an increase in collagen content. By contrast, percent collagen increased logarithmically from Day 7 to Day 14, and this was similar to the increase in the modulus of the tissue. Importantly, there was no relationship between passage number and mechanical function or collagen content in the two independent donors tested. These results suggest that the model develops quickly and is reliable across differing passage numbers. This provides the field with the ability to 1) consistently determine functional changes of interventions out to passage number 10; and 2) to time interventions to the appropriate developmental stage: developing/regenerating (Day 7) or mature (Day 14) tissue.

Comprehensive parametric analyses on the mechanical performance of 3D printed continuous carbon fibre reinforced plastic

This study presents a novel in-house modelling method called “Fibre Path Generator” and comprehensive parametric analyses on the mechanical performance of carbon fibre reinforced plastic (CFRP) with the fibre path along the principal stress direction, using both finite element (FE) simulations and experiments. The reliability of the developed CFRP model is validated through the fabrication of open-hole tensile test specimens using a co-extrusion composite 3D-printer, which demonstrated a highly compatible maximum tensile load with an error less than 3%. A comparative analysis is conducted to assess the mechanical performance of the CFRP specimen with principal stress fibre placement, which result shows that the maximum tensile load achieved is 172.84% higher than a CFRP model with uniaxial fibre placement. Furthermore, comprehensive parametric studies are carried out, varying the carbon fibre location and width-to-depth (w/D) ratio of the open-hole specimen, in order to evaluate the mechanical performance under the tensile loading. This study results provide useful insights to engineers when enhancing the mechanical performance of CFRP composite structures with effective continuous fibre placement.

Evolution of bonding mechanism and fracture mechanism of Ti alloy-steel joint by dual-beam laser welding using Mg-RE (RE=Gd, Y) filler

In this paper, a novel coaxial continuous-pulsed dual-beam laser was proposed to join TC4 titanium alloy with QP980 high-strength steel, and magnesium alloy containing rare-earth elements (Mg-RE) was creatively as filler. The weld appearance, microstructure and mechanical properties of joints obtained by single-beam and dual-beam laser welding were compared and analyzed. And the evolution of bonding mechanism and the fracture mechanism with laser beam energy density was analyzed. The results showed that the appearance and mechanical strength of the joint obtained by dual-beam laser were better than that by single-beam laser. And the maximum tensile shear load of TC4/QP980 lap joint welded by dual-beam laser reached 303 N/mm, which was 124 % of that of single-beam laser welding. The bonding of Mg-RE with QP980 affected by temperature of laser welding and mainly depended on Gd and Y. They just diffused to QP980 under low power and reacted with Fe under high power. And the inter-diffusion of Zr of Mg-RE with Ti of TC4 produced to the bonding of Mg-RE with TC4. The roles of continuous laser and pulsed laser in dual-beam laser welding were revealed in this paper and it showed a great application potential of coaxial dual-beam laser welding technology in dissimilar metal joining.

Evaluation of ultrasonic spot welded Al-Cu dissimilar sheets: Mechanical performance, microstructural changes and thermal analysis

Automotive lithium-ion battery manufacturing industries are increasingly using ultrasonic welding (USW) to join thin dissimilar metals and foils. USW has good joint efficiency, no formation of the heat-affected zone, high production rate, shorter welding time, and sustainability over conventional fusion welding techniques. However, this process is less distinct and precise control of weld surface conditions to get good quality welds. In this regard, experimental and thermal analysis significantly helps to control the state of the weld interface during the joining process. In this study, the objective is to enhance the mechanical performance of aluminum (Al) and copper (Cu) joints under different surface conditions such as lubricating, normal, electrolytically, and emery polished. According to the lap shear tensile load result, the joint strength decreases significantly with the rise in weld time after 0.7 s. The lubricating surface provides the maximum lap shear tensile load of 1507 N among all other surface conditions. Fracture surface analyses are conducted to determine the quality of welds under varying surface conditions. Additionally, a three-dimensional (3D) finite element model (FE) for ultrasonic welding of two highly conductive metal sheets is also being investigated for the purposes of analysing the thermal behaviour around the weld interface. It reveals that the thermal profile of the interface differs depending on the surface condition. The numerical framework is confirmed by comparing the predicted interface temperature variations at different faying surface conditions with the experimental results.

A comparative study on adhesive properties of nanoparticle reinforced epoxy bonded single-strap repaired composites

Abstract This study aimed to evaluate the impact of nanoparticle inclusion and patch size on the bonding performance of single-strap repaired glass-reinforced composite plates through experimental investigations. Epoxy adhesive was modified with three different nanoparticles: nano-silica (NS), nano-graphene (NG), and nano-clay (NC) at varying weight contents. The patch repair performance of the test samples was evaluated using two patch ratios (Patch diameter (D)/Hole diameter (d) = 2 and 3) to explore the influence of patch size on repair effectiveness. GFRP composite base plates having a 10 mm diameter hole in the middle were patch repaired by using patches with the same material. Tensile tests were conducted to compare the tensile performance of the repaired composite samples, and the results were compared with the samples with and without holes. Based on the findings, it was noted that samples with a larger patch ratio (D/d = 3) can withstand higher tensile loads compared to those with a patch ratio of 2. Moreover, it was found that the specimen repaired with 3 % by weight NC-filled epoxy adhesive showed the greatest increase in tensile load value. This increase was recorded at both patch rates, with a percentage improvement of 2.8 and 19.54 % compared to pure epoxy adhesive. Also, it was observed that when the patch ratio was 3, the 3 % NS-filled adhesive showed an increase of 3.3 %. On the other hand, all combinations of NG-filled adhesive showed a decrease in maximum tensile load values.