Strength Behavior Research Articles

Strength Behavior Analysis of Self-healing Concrete Using Bacteria and Silica Gel: A Comparative Study

Strength Behavior Analysis of Self-healing Concrete Using Bacteria and Silica Gel: A Comparative Study

Repurposing plastic waste: Experimental study and predictive analysis using machine learning in bricks

The construction industry significantly contributes to environmental degradation and resource depletion. This paper investigates the use of waste plastic from post-consumer and post-industrial sources as a sustainable alternative in brick manufacturing. By substituting plastic waste for traditional materials like clay or cement, the ecological footprint of brick production is reduced, and plastic pollution is mitigated by diverting waste from landfills and oceans. This study employs dual approach of experimentation as well as machine learning for assessing the strength behaviour of bricks enhanced with plastic, emphasising compressive strength, durability, thermal insulation, and moisture resistance. Utilization of Chlorinated Polyvinyl Chloride (CPVC) for Waste plastic bricks (WPB) was done by replacing cement and sand in different proportions i.e. 10 %, 20 %, 30 %, 40 %, and 50 % of fly ash bricks The best performance was observed at 30 % replacement of sand with waste CPVC. A Deep Neural Network (DNN) model also predicted compressive strength and water absorption, identifying key material components influencing brick properties through SHAP value analysis. This combined experimental and predictive modelling approach demonstrates the potential of waste plastic in creating lightweight, sustainable building materials for structural applications, contributing to sustainable construction practices.

Optimizing strength behavior of sustainable ultra high performance green concrete with minimum cement content using response surface method

Optimizing strength behavior of sustainable ultra high performance green concrete with minimum cement content using response surface method

Bond Strength Assessment of Normal Strength Concrete-Ultra-High-Performance Fiber Reinforced Concrete Using Repeated Drop-Weight Impact Test: Experimental and Machine Learning Technique.

Ultra-high-performance concrete (UHPC) has been used in building joints due to its increased strength, crack resistance, and durability, serving as a repair material. However, efficient repair depends on whether the interfacial substrate can provide adequate bond strength under various loading scenarios. The objective of this study is to investigate the bonding behavior of composite U-shaped normal strength concrete-ultra-high-performance fiber reinforced concrete (NSC-UHPFRC) specimens using multiple drop-weight impact testing techniques. The composite interface was treated using grooving (Gst), natural fracture (Nst), and smoothing (Sst) techniques. Ensemble machine learning (ML) algorithms comprising XGBoost and CatBoost, support vector machine (SVM), and generalized linear machine (GLM) were employed to train and test the simulation dataset to forecast the impact failure strength (N2) composite U-shaped NSC-UHPFRC specimen. The results indicate that the reference NSC samples had the highest impact strength and surface treatment played a substantial role in ensuring the adequate bond strength of NSC-UHPFRC. NSC-UHPFRC-Nst can provide sufficient bond strength at the interface, resulting in a monolithic structure that can resist repeated drop-weight impact loads. NSC-UHPFRC-Sst and NSC-UHPFRC-Gst exhibit significant reductions in impact strength properties. The ensemble ML correctly predicts the failure strength of the NSC-UHPFRC composite. The XGBoost ensemble model gave coefficient of determination (R2) values of approximately 0.99 and 0.9643 at the training and testing stages. The highest predictions were obtained using the GLM model, with an R2 value of 0.9805 at the testing stage.

Sustainable mortar reinforced with recycled glass fiber derived from pyrolysis of wind turbine blade waste

Pyrolysis technology has recently made significant progress in recycling millions of tons of wind turbine waste (WTB). Short fibers represent its main product (∼70 wt%), which needs further studies to explore its future applications. In this context, this work aims to the valorization of the recycled glass fiber (rGF) derived from pyrolysis of WTB (at 550 °C) in the production of rGF-reinforced mortar composite (rGF/M) for sustainable building applications. The research began by subjecting the derived rGF to sieving (rGFs), washing (rGFw), and oxidation (rGFo) pretreatments for purification and removing any impurities, organic residues, and char particles. Afterward, the chemical degradation of the treated rGF in a strong alkaline cement solution with pH = 14 was studied for up to 90 days. In parallel, the mortar composite samples were fabricated at 1 wt% of the treated rGF batches (rGFr, rGFw, and rGFo) to study the effect of different pretreatments on their microstructure, dispersion, compressive strength, flexural strength, and water absorption capabilities behavior after different curing periods (28 and 90 days). The results showed that rGFo (7.84%) showed a lower degradation rate versus rGFw (16.41%) and rGFr (30.76%). Meanwhile, the highest curing period (90 days) contributed to improving the properties of the mortar composites in general, especially in the case of using rGFo which led to improved compressive strength (15%) and reduced absorption coefficient (38%) and cumulative water content (32%) with a uniform distribution of short fibers in the matrices and a slight increase in flexural strength compared to control mortar sample (8.6 MPa). While rGFs provides better flexural strength (9.3 MPa) with a 12% improvement. Based on these results it can be concluded that rGFo has high potential in sustainable building materials with high competition with virgin glass fiber.

Multiscale microstructural consideration for high strength diffusion bonding of Ti2AlNb alloy to GH4169 superalloy with (TiZrHfNb)95Al5 interlayer

A high entropy interlayer (TiZrHfNb)95Al5 was successfully designed for vacuum diffusion bonding of GH4169 superalloy to Ti2AlNb alloy. The relationships between grain size, grain boundary, lattice mismatch and microhardness, elastic modulus, shear strength and fracture behaviors were revealed. The typical microstructure was Ti2AlNb/B2/Solid solution/(Ti, Zr, Hf)2(Ni, Nb)+(Ti, Zr, Hf)(Ni, Nb) + Solid solution/(Ti, Zr, Hf)(Ni, Nb) + (Cr, Ni, Fe)ss/(Cr, Ni, Fe)ss/Cr-rich(Cr, Ni, Fe)ss/Ni-rich(Cr, Ni, Fe)ss/GH4169. With the holding time increased, the shear strength overall increased and decreased sharply, and the highest shear strength reached 384 MPa at 980 °C for 90 min. The microstructure had anisotropic crystal orientation, and the joints of Zone Ш for 90 min consisted of 92.08 % HAGBs and 7.92 % LAGBs. The residual strains and stresses decreased when the holding time increased. Meanwhile, recrystallisation appeared in Zone Ш, and the increase in the recrystallisation rate led to grain refinement. The lattice mismatch between (Ti, Zr, Hf)(Ni, Nb) and (Cr, Ni, Fe)ss phases was 25.05 %, indicating that the interface was non-coherent, and (Ti, Zr, Hf)(Ni, Nb)+(Cr, Ni, Fe)ss phases were located at an elastic modulus dramatically changed interface. Thus, the cracks easily formed in this interface and led to joint fracture. Moreover, the fracture mechanism was brittle fracture.

Influence of Borides on microstructure and mechanical properties of a Ni alloy

Abstract Ni alloys are known to exhibit superior creep strength, chemical stability, and thermal resistance behavior at elevated temperatures. However, they also exhibit inadequate mechanical performance. Hence, the microstructures and, in relation to that, mechanical properties need to be improved. In this study, the effect of reinforcement of TiB2 on microstructural and mechanical properties was evaluated. The Ni matrix is reinforced with TiB2 particles. TiB2–Ni composites were successfully produced by the hot pressing method. Homogenously distributed TiB2 particles were observed in the microstructure using the energy dispersive spectrometry (EDS) mapping technique. The hardness of the reinforced samples was considerably improved by 2.65–8.12 times compared to pure Ni and between the different content of borides. A three-point bending test was performed to examine the mechanical behaviors of the reinforced composites. The bending stress properties of metal matrix composite (MMC) were significantly influenced by TiB2 content both positively and adversely. The optimum chemical content was determined based on bending tests and fractography. As a result, the 15 wt.% TiB2-reinforced sample exhibited superior microstructural (density), hardness, and bending properties compared to pure Ni and other reinforced samples with different ratios.

An in vitro evaluation of bond strength and failure behavior between 3D-printed cobalt-chromium alloy and different types of denture base resins

ObjectivesThis study aimed to evaluate the shear bond strength and failure behavior between cobalt-chromium (Co-Cr) alloy and different types of denture base resins (DBRs) over time. MethodsSeventy-two disk-shaped specimens (8 mm in diameter and 2 mm in thickness) were manufactured using a selective laser melting technology-based metal 3D printer. Three types of DBRs were used: heat-cure (HEA group), cold-cure (COL group), and 3D-printable (TDP group) DBRs (n = 12 per group). Each DBR specimen was fabricated as a 5 mm × 5 mm × 5 mm cube model. The specimens of the TDP group were manufactured using a digital light processing technology-based 3D printer. Half of the DBRs were stored in distilled water at 37 °C for 24 h, whereas the remaining half underwent thermocycling for 10,000 cycles. Shear bond strength was measured using a universal testing machine; failure modes were observed, and metal surfaces were evaluated using energy dispersive spectrometry. ResultsThe shear bond strength did not differ between the DBR types within the non-thermocycled groups. Contrarily, the TDP group exhibited inferior strength compared to the HEA group (P = 0.008) after thermocycling. All three types of DBRs exhibited a significant decrease in the shear bond strength and an increased tendency toward adhesive failure after thermocycling. ConclusionsThe bond strength between 3D-printable DBRs and Co-Cr alloy was comparable to that of heat-and cold-cure DBRs before thermocycling. However, it exhibited a considerable weakening in comparison to heat-cure DBRs after simulated short-term use. Clinical SignificanceThe application of 3D-printable DBR in metal framework-incorporated removable partial dentures may be feasible during the early phase of the treatment. However, its application is currently limited because the bond strength between the 3D-printable DBR and metal may weaken after short-term use. Further studies on methods to increase the bond strength between these heterogeneous materials are required.

Thermo-mechanically joined hybrids from carbon fiber-reinforced PA12 with die-cast alloy AlSi10Mg: how surface and interlayer design affect shear strength and fracture behavior

ABSTRACT Infrared radiation was used as a tool to heat laser-structured AlSi10Mg for subsequent fusion bonding with thermoplastic carbon fiber-reinforced PA12. When the two adherends are brought into contact, the bond is formed by melting of the surface-near polymer matrix and pressing it into the laser structure of the aluminum alloy. When investigating different fiber volume contents, the amount of fusible material was identified as a key parameter for the achievable bonding strength. Therefore, the best results were achieved with low fiber volume content (25 vol.-%) or under the use of an additional PA12 interlayer. Moreover, the influence of different surface texture parameters was investigated and the aspect ratio between structure depth and width was found to correlate best with the measured shear strengths. Aspect ratios from 0.18 to 1.15 increased the bond strength up to the interlaminar shear strength of the thermoplastic composite. Especially, aspect ratios of 0.61 or greater proved to be very effective, with resulting mean strength values of almost 30 MPa. While even lower ratios allowed higher loads on the joints compared with untreated surfaces, greater aspect ratios show lower bond strengths, as the laser structures were no longer completely filled with fused PA12.

Исследования соединений AA7075, сваренных трением с перемешиванием и ультразвуковым воздействием: механические свойства и анализ разрушения

Introduction. Joint efficiency and strength, particularly in aluminum alloys, are crucial in aerospace, defense, and industrial applications. Post-welding treatments like shot peening and laser shock peening significantly improve joint efficiency and strength, enhancing fatigue life, grain structure, and tensile strength. The purpose of the work. The literature reviewed shows that the ultrasonic vibration-assisted friction stir welding (UVaFSW) and post-weld treatment improved the mechanical properties and material flow. However, limited studies have been observed on the UVaFSW joints of AA7075-T651, considering the consequence of welding speed, tool rotation, and post-weld shot peeing treatment. The methods of investigation. The study investigates the ultrasonic vibration-assisted friction stir welded (UVaFSwed) AA7075-T651 joint's tensile strength, microhardness, microstructure, and fracture behavior, considering the impact of tool rotation, welding speed, and post-weld shot peening treatment. Results and Discussion. The post-weld treated shot-peened UVaFSWed joints demonstrated the maximum tensile strength of 373.43 MPa, the microhardness of 161 HV, and the lowest surface roughness of 15.16 µm at 40 mm/min welding speed when compared to the friction stir-welded (FSWed) joints. These results indicate that shot peening improved the mechanical properties and surface quality of the UVaFSWed joints. The high tensile strength and low surface roughness make these joints suitable for applications requiring strength and aesthetics. The fracture for the shot peened UVaFSWed joints mainly occurred in the heat-affected zone (HAZ) during the tensile test. It could be attributed to the higher temperature experienced during welding, which resulted in grain growth and decreased material strength in the HAZ. The shot-peened UVaFSWed joint has a more uniform grain distribution than the FSWed one, which contributed to the joint's higher tensile strength. The fractured surface of the shot peened UVaFSWed joints showed larger, equiaxed, and shallow dimples, resulting in higher ultimate tensile strength (UTS) and microhardness compared to the conventional FSWed joints. The mechanical properties and microstructure observed in the welding zones of shot peened UVaFSWed joints are superior to those of conventional FSW joints. However, further investigation is required to determine the specific factors contributing to this localized failure at HAZ, considering the effects of shot peening parameters. This study also suggests the potential for optimizing shot peened UVaFSWed joints of AA7075-T651.

Characteristics of concrete incorporating construction and demolition waste aggregate and post-consumer tires rubber and steel fibers

This study aims at investigating the performance of Portland cement concrete incorporating construction and demolition waste aggregate in conjunction with rubber and steel fibers from post-consumer tires. Eight concrete mixes were prepared and tested. In these, natural coarse aggregate (NCA) was replaced by 100 % recycled concrete aggregate (RCA) and/or 20 % and 40 % rubber coarse aggregate (RuCA). The contribution of post-consumer tire steel fibers (PCTSF) to the behavior of the various recycled concrete mixes was also examined. The axial compressive stress–strain, flexural stress–deflection, and splitting tensile strength behaviors together with the dry density, porosity and rapid chloride penetration for all concrete mixes were investigated and compared. The results indicated that increasing the replacement levels of RuCA resulted in a decrease in concrete strength, although the decrease was less pronounced in the concrete mixes with RCA than in mixes incorporating NCA. Specifically, the reductions in compressive, tensile and flexural strengths were respectively as much as 6.6 %, 12.9 % and 14 % less in the mixes containing RCA. Also, the addition of PCTSF substantially mitigated the reductions in strength and, more significantly, the deflection at peak stress was increased by up to 664 %. Furthermore, incorporation of these fibers maintained up to 47 % of the flexural peak strength of the concrete mix at 4 mm deflection in the post-peak region. Additionally, the porosity of the concrete mixes ranged from 6 % to 12 %, placing them in the high-durability concrete category. The dry density exhibited an inverse relationship with the rubber aggregate content, resulting in a reduction of up to 10.2 % compared to the control mix. Hence, utilizing a substantial volume of post-consumer tire materials in recycled-aggregate concrete mixes is envisaged as an ideal choice in construction applications where lower concrete rigidity is desired, for example in seismic or vibrated zones. The approach also aligns with the increasing emphasis on sustainable construction materials.

Compaction and shear characteristics of recycled construction & demolition aggregates in subgrade: Exploring particle breakage and shape effects

Recycling construction and demolition (C&D) wastes into useable aggregates in subgrade applications offers significant sustainability benefits. However, the characteristics of recycled aggregates, including particle morphology, crushing strength, and shear behavior, differ substantially from natural aggregates. This paper presented an extensive experimental study on the compaction and mechanics performances of recycled concrete and brick aggregates, with a particular focus on the effects of particle breakage and shape characteristics. The compaction of recycled aggregate specimens comprising three structural types was evaluated using heavy Marshall compaction (HMC) and Superpave gyratory compaction (SGC). The compaction characteristics and particle breakage were examined, enabling a profound understanding of the compaction mechanisms associated with both methods. Furthermore, triaxial shear tests were performed to scrutinize the influences of particle shape, compaction degree, and confining pressure on shear characteristics. Results showed that after 80 gyratory rotations in SGC, the compaction degree of recycled aggregates aligned with the targeted results obtained from HMC. Changes in fractal dimension after compaction exhibited direct correlations with the two-dimensional shape distribution. Axial coefficient, fractal dimension and confining pressure most strongly influenced shear strength. In light of these insights, prediction models for shear strength parameters were proposed using multiple regression analysis. Overall, the study provides valuable insights into the relationships between aggregate morphology, compaction response, breakage behavior, and shear performance. These findings can facilitate optimized design and construction using recycled aggregates to advance sustainable infrastructure development.

Experimental investigation of the effect of longitudinal tensile reinforcement ratio on ductility behaviour in GPC beams

This research first determined the strength of the cylindrical geopolymer concrete materi- als under compressive stresses. Secondly, conventional and geopolymer-reinforced concrete beams were manufactured in different reinforcement ratios, and their mechanical properties were compared under bending. The main aim of this study is to experimentally compare the effect of reinforcement ratio on the ductility behavior of an alkali-activated geopolymer con- crete (GPC) beam with that of an ordinary Portland cement (OPC) beam. First, balanced reinforcement calculations were made considering the mechanical properties obtained from the material tests. The load-displacement, moment-curvature, and crack development results obtained from beam tests are interpreted with this information. OPC and GPC beams exhibit- ed similar strength and crack development behavior. However, the behavior of GPC and OPC concretes differs regarding the ductility index. Therefore, to achieve similar ductility in the conduct of GPC and OPC beams, the balanced reinforcement ratio and section dimensions of GPC beams should be chosen to be larger than OPC.

Carbohydrate-Based Reprocessable and Healable Covalent Adaptable Biofoams.

Polymeric foams derived from bio-based resources and capable of self-healing and recycling ability are of great demand to fulfill various applications and address environmental concerns related to accumulation of plastic wastes. In this article, a set of polyester-based covalent adaptable biofoams (CABs) synthesized from carbohydrates and other bio-derived precursors under catalyst free conditions to offer a sustainable alternative to conventional toxic isocyanate-based polyurethane foams is reported. The dynamic β-keto carboxylate linkages present in these biofoams impart self-healing ability and recyclability to these samples. These CABs display adequate tensile properties especially compressive strength (≤123MPa) and hysteresis behavior. The CABs swiftly stress relax at 150°C and are reprocessable under similar temperature conditions. These biofoams have displayed potential for use as attachment on solar photovoltaics to augment the output efficiency. These CABs with limited swellability in polar protic solvents and adequate mechanical resilience are suitable for other commodity applications.

Mechanical strength and low-velocity impact behavior of glass fiber reinforced filament wound pipes with different number of layers after hydrothermal aging

Composite pipe is preferred over metal and other materials for water supply, liquid chemical transport, and fuel and gas transport. This is because composite pipes are more corrosion resistant, have a high strength/density ratio, high stiffness/density ratio, and more durable than metal pipes. The properties of the composite pipes employed may differ based on the operating environment. Therefore, determining the properties of the composite pipe according to the working environment is extremely important for its lifespan. The thickness of the samples is increased in line with different needs (such as increased strength). Increasing the thickness of samples, especially those exposed to different environmental conditions, and investigating the changes that will occur in the physical and mechanical properties of the samples are another important situation. In this investigation, glass fiber (GFRP) reinforced epoxy composite pipes have been examined, which were manufactured using the filament winding method with different layers [±55°]. To determine their properties in different working environments, the GFRP composite pipes were subjected to hydrothermal aging in pure water at 80°C for several days (7, 14, 21, and 28). The changes in their mechanical properties under working conditions were determined through hoop tensile strength tests and low velocity impact tests applied at different energy levels. The experimental results show that the tangential stress values increased by 10.59% as the number of layers increased. As the aging time increased, the durability of the 6-layer composite pipe decreased by 17.69%. Furthermore, the ability of the aged pipes to withstand damage was evaluated, revealing that the aging process exacerbated the damage within the pipes.

Scanning electron microscopy (SEM)-assisted mechanistic study: pH-driven compressive strength and setting time behavior in geopolymer concrete

This research study investigates the influence of pH on the setting time, compressive strength (CS), and surface roughness of different waste materials, namely fly ash, rice husk ash (RHA), red mud, and ground granulated blast furnace slag (GGBS). The average pH values for these waste materials were found to be 8.77, 9.3, 8.3, and 11, respectively. The initial setting time (IST) and final setting time (FST) varied among the materials, with red mud having maximum IST and FST with a value of 180 min and 24 h. CS (MPa) measurements revealed that GGBS exhibited the highest value of 36 MPa, followed by RHA (28 MPa), red mud (22 MPa), and fly ash (24 MPa). Surface roughness analysis showed that red mud had the highest roughness value of 69.71, followed by fly ash (62.81), RHA (53.14), and GGBS (49.08). The findings indicate a positive correlation between pH levels and CS of 97%, and setting time surface roughness has a negative correlation with CS when analyzed with a heatmap. Higher pH values were associated with increased CS, particularly after 28 days of curing which is shown by the heatmap and sub-plots. Additionally, microscopic analysis provided insights into particle size, orientation, and clustering, aiding in understanding the bonding and reactivity patterns contributing to the observed variations in CS.

Investigation and performance analysis of eco-friendly coco fiber concrete hybridized with CNT blend

With the development of the technical trend, concrete using waste alternate material instead of sand material found economic potential for good structural behaviour. Besides, the susceptible crack, low strength-to-weight ratio, and low compressive strength are the reasons for shrinkage. Due to this reason, the investigation aims to limit the shrinkage under live load and increase the compression and flexural strength by the introduction of coconut waste chopped fiber (wCF), waste fly ash (wFA), and carbon nanotube powder (CNT) blended with conventional Portland paste. The developed concrete consists of 5 wt% wCF, 10 wt% wFA, and 0, 5, 10, and 15 wt% of CNT and is subjected to X-ray diffraction analysis, bulk density, compression and flexural strength, and water absorption studies. The X-ray diffraction pattern revealed the wCF, wFA, CNT, and matrix compositions. The concrete developed with 5 wt% wCF, 10 wt% wFA, and 15 wt% CNT cured within 28 days recorded maximum behaviour of compression strength (47 ± 1.8 MPa), flexural strength (4.9 ± 0.19 MPa), and water absorption of (2.8 ± 0.05 %).

Molecular line polarisation from the circumstellar envelopes of asymptotic giant branch stars

Context. Polarisation observations of masers in the circumstellar envelopes (CSEs) around asymptotic giant branch (AGB) stars have revealed strong magnetic fields. However, masers probe only specific lines of sight through the CSE. Non-masing molecular line polarisation observations can more directly reveal the large-scale magnetic field morphology and hence probe the effect of the magnetic field on AGB mass loss and the shaping of the AGB wind. Aims. Observations and models of CSE molecular line polarisation can now be used to describe the magnetic field morphology and estimate its strength throughout the entire CSE. Methods. We used observations taken with the Atacama Large Millimeter/submillimeter Array (ALMA) of molecular line polarisation in the envelope of two AGB stars: CW Leo and R Leo. We modelled the observations using the multi-dimensional polarised radiative transfer tool PORTAL. Results. We found linearly polarised emission, with maximum fractional polarisation on the order of a few percent, in several molecular lines towards both stars. Towards R Leo, we also found a high level of linear polarisation (up to ∼35%) for one of the SiO v = 1 maser transitions. We can explain the observed differences in polarisation structure between the different molecular lines by alignment of the molecules through a combination of the Goldreich-Kylafis effect and radiative alignment effects. We specifically show that the polarisation of CO traces the morphology of the magnetic field. Competition between the alignment mechanisms allowed us to describe the behaviour of the magnetic field strength as a function of the radius throughout the circumstellar envelope of CW Leo. The magnetic field strength derived using this method is inconsistent with the magnetic field strength derived using a structure-function analysis of the CO polarisation and the strength previously derived using CN Zeeman observations. In contrast with CW Leo, the magnetic field in the outer envelope of R Leo appears to be advected outwards by the stellar wind. Conclusions. The ALMA observations and our polarised radiative transfer models show the power of using multiple molecular species to trace the magnetic field behaviour throughout the circumstellar envelope. While the observations appear to confirm the existence of a large-scale magnetic field, further observations and modelling are needed to understand the apparent inconsistency of the magnetic field strength derived with different methods in the envelope of CW Leo.

Mechanical and wear characteristics of aluminium-7075/graphene/TiB2 prepared by stir casting

The rapid development of Aluminium composites with advanced hybrid materials is increasing due to increasing demand. This composite material is used in many applications in the aerospace and automotive industries due to its lightweight, good corrosion resistance and high thermal resistance. To meet this demand, this study focused on the development of Al-7075 alloy reinforcements containing TiB2 and graphene, using Aluminium-7075 as the base material, mixed with TiB2 and graphene to measure and improve mechanical and tribological properties by using stir casting technique, with the proposed graphene content of 1%, 2% and 3% and TiB2 content varying between 1 to 15% of its overall weight. With the addition of TiB2 and graphene properties such as hardness, tensile strength, impact strength and tribological behaviour are improved. The 12% reinforcement combination (i.e. 10% TiB2 and 2% Gr) exhibit better tensile strength, hardness and wear resistance. Microstructure and phase characterization of the composite material are analyzed using scanning electron microscopy (SEM) and x-ray diffraction (XRD) techniques. A microstructure evaluation is employed to justify the homogenous dispersal and the existence of reinforced particles. To ensure the quality and reliability of products made from these alloys, destructive tests are often conducted to evaluate their mechanical properties and behavior under different loading conditions.

Bamboo as a natural optimized fiber reinforced composite: interfacial mechanical properties and failure mechanisms

Bamboo is a typical natural fiber-reinforced composite with an optimized distribution of vascular bundles as reinforcement and parenchyma tissues as bio-matrix. The interfacial bonding performance between vascular bundles and parenchyma tissue is critical for the mechanical properties and failure mechanisms of bamboo. This study employed pull-out tests to determine the interfacial shear strength (IFSS) between bamboo vascular bundles and parenchyma tissue and evaluate the critical embedded lengths () of vascular bundles. The effects of embedded vascular bundle lengths on interfacial strength and failure behaviors were also investigated. The results revealed a value of 2.51 mm, lower than the majority of plant fiber-reinforced composite materials, with an IFSS of around 20 MPa, surpassing most artificial bamboo fiber composites. The pull-out process of the vascular bundles involved elasticity, debonding, and sliding friction stage, where debonding energy absorption (DEA) outweighed frictional energy absorption (FEA) and increasing with embedded length. The primary failure features include interfacial debonding, parenchyma tissue ripping, delamination of fiber thin layers, and fiber breakage. Moreover, the parenchyma cells between the two fiber sheaths and at the top of the bamboo block readily detached. The interfacial failure mechanisms of bamboo included debonding, reinforcement, and matrix failure, with the proportions varying as the embedded length increased. Quantitative analysis of the interfaces structure and mechanical properties between vascular bundles and parenchyma tissues could provide a reference for the biomimicry of bamboo structures and the manufacturing of natural fiber-reinforced composite materials.