Tensile Strength Research Articles

Study on the Formation and Mechanical Stability of Retained Austenite in Complex Phase Steel with High Formability

Herein, a 1300 MPa grade complex phase steel with high formability (CH) is developed, which is achieved through the formation of cementite during pretreatment and the control of austempering temperature to enhance the stability of retained austenite (RA). Due to the insufficient diffusion of Mn during cementite dissolution, Mn enrichment enhances the mechanical stability of austenite, thereby increasing austenite content at room temperature. As the austempering temperature increases from 340 °C to 400 °C, the RA content increases, but its stability decreases significantly. Compared with the content of RA, its stability is more critical for enhancing plasticity. RA formed at lower austempering temperatures is highly stable, enlarging the strain range of the transformation‐induced plasticity effect and improving material plasticity. The experimental steel achieves optimal plasticity while maintaining strength when overaged at 360 °C. Specifically, the yield strength is 963 MPa, the ultimate tensile strength is 1394 MPa, and the total elongation is 14.0%.

Performance Research and Engineering Application of Fiber-Reinforced Lightweight Aggregate Concrete

Low strength and low impact toughness are two of the main issues affecting the use of lightweight aggregate concrete in harsh cold environments. In this study, the strength of concrete was improved by adding high-strength fibers to bear tensile stress and organize crack propagation. Four sets of comparative experiments were designed with freeze–thaw cycles of 0, 50, 100, and 150 to study the mechanical properties of fiber-reinforced lightweight aggregate concrete under freeze–thaw conditions. A detailed study was conducted on the effects of freeze–thaw on the compressive strength, flexural strength, impact toughness, and microstructure of concrete with different fiber contents (3, 6, and 9 kg/m3). The results show that for ordinary lightweight aggregate concrete, under the freeze–thaw cycle, the internal pore water of the concrete froze and generated expansion stress, resulting in tensile cracks inside the concrete. The cracks gradually accumulated and expanded, ultimately leading to cracking and damage of concrete structures. After 150 cycles, the strength loss rate exceeded 25%. When adding a reasonable amount of fiber (6 kg/m3), the fiber took on the tensile stress and hindered the development of internal cracks, significantly enhancing the splitting tensile strength, flexural strength, and impact toughness of lightweight aggregate concrete. And the failure pattern of concrete was significantly improved. At the beginning of the freeze–thaw cycle, the internal tensile stress was less than the fiber tensile strength and the fiber–matrix bonding strength, and the strength reduction rate of the concrete was slow. Relying on the friction absorption capacity between the fiber and the matrix, the fiber used its own deformation to resist the tensile stress. In the late stage of the freeze–thaw cycle, due to the destruction of the fiber–matrix transition zone structure, the bond strength decreased, the crack resistance and toughening effect decreased, and the strength of the concrete decreased rapidly. Moreover, the reduction in impact toughness was greater than the compressive strength and flexural strength under static load.

Mechanical and dynamic characteristics for the CFRP, GFRP, and hybrid composites exposed to HCl environment

In the current study, the low-velocity impact (LVI) characteristics of carbon fiber-reinforced polymer (CFRP), glass fiber-reinforced polymer (GFRP), and hybrid composites before and after the corrosive environment exposure were investigated. In this regard, CFRP, GFRP, and hybrid composites were subjected to LVI and tensile loadings after being kept in a 10% diluted HCl environment for 1 week and 1 month, and the impacts of the corrosive environment on the composites’ dynamic and mechanical responses were determined by comparing the outcomes of the control and aged specimens. LVI tests for CFRP, GFRP, and hybrid composites were carried out by transferring 25.2 and 11.2 J impact energy to the specimens with two impact velocities of 3 and 2 m/s, respectively, and thus, the effects of impact energy and hybridization were investigated. Moreover, tensile tests were conducted for the control and aged specimens with 2 mm/min crosshead speed, and thus, the effects of fiber material, hybridization, and corrosive environment on the mechanical properties were determined. The study found that CFRP composites had higher stiffness than GFRPs, whereas hybrid composites exhibited dynamic responses between CFRP and GFRP, as expected. On the other hand, it turned out that the composites absorbed most of the impact energy, which was interpreted as being absorbed by the damage of fiber-reinforced composites, which stand out with their brittle characteristics. Furthermore, it was discovered that the damage severity elevated as expected with a longer aging time, which was attributed to the corrosive liquid attacking the fibers, matrix, and fiber/matrix interfaces and reducing strength. It was also observed that, as predicted, the corrosive effects generally resulted in a reduction in tensile responses, including ultimate strain and tensile strength.

Development of rare earth element-based hybrid aluminium composites using stir casting process.

Aerospace and marine industries are constantly in search of materials that can provide good strength and durability while also being lightweight. Aluminium composites with adequate reinforcements have been proven to be effective in achieving incredible mechanical properties while also maintaining a good strength to weight ratio. Numerous studies have been done to study the various possibilities of matrix reinforcement combinations in aluminium composites. This work focuses on studying the effect of varying Cerium Oxide (CeO2) percentage in the aluminium composite on its tensile strength, hardness and corrosion resistance. CeO2 is used along with Silicon Carbide (SiC) and Multi-Walled Carbon Nanotubes (MWCNT) to develop four samples of hybrid aluminium composites with SiC and MWCNT constituting 1% and 0.1% of the composite and the weight percentage of CeO2 is varied between 1 and 2.5%. All the samples were fabricated using the modified stir casting process. The results show that the hardness and tensile strength of the composites peak when the CeO2% is at 2% while corrosion resistance only gets better with increasing reinforcement content. A significant enhancement in mechanical and physical properties of aluminium composite suggests that MWCNT is an effective hybridizing agent with SiC and CeO2 to develop aluminium composites.

Effect of Laser Power on Weld Formability and Residual Stress of Unequal Thickness 410 Ferritic Stainless Steel/RCL540 Low-Carbon Alloy Steel

In this paper, the butt joint of unequal thickness 410 ferritic stainless steel and RCL540 low-carbon alloy steel sheets are realized by laser welding. The effects of different laser powers on weld formability, mechanical properties, and residual stress in the welding process are investigated. It is observed that with increasing laser power, the heat accumulates at the bottom of the molten pool and weld metal, causing the ratios of upper and lower melt widths to decrease. The tensile test results show that all specimens fractured in the weak zone of the base metal on the stainless steel side at 10 mm from the weld seam. The residual stress distributions of the specimens are calculated using ABAQUS 2022 software and compared with the measurements of the blind-hole method. It is found that the stainless steel side produces tensile stresses, with the power increase offset by compressive stresses in the base metal. When the laser power is 1200 W, the welded joint has the best weld formability and mechanical properties and the least residual stress. The upper and lower melt width ratio is 1.17, the maximum microhardness of the weld metal is 374.7 HV, the maximum test force and tensile strength are 5617.5 N and 468.12 MPa, respectively, and the minimum values of the transverse and longitudinal stresses are −45.8 MPa and −106.4 MPa, respectively.

The Mechanical Properties of Aged PA-12 FS3300PA Powder: Influence of Layer Thickness, Sintering Orientations, and Laser Power

Abstract This research investigates the influence of layer thickness, laser power, and sintering orientation on the mechanical properties of aged Polyamide-12 (PA-12) FS3300PA using the Selective Laser Sintering (SLS) 3D printing method. Specimens were sintered with three different layer thicknesses, laser powers, and sintering orientations using SLS. The study also aimed to examine the resulting powder morphology, mechanical properties, and tensile fracture behaviors of the aged (more than eight continuously sintering cycles) and virgin FS3300PA powders. The specimens divided into ten groups: nine groups of aged powder and one group of virgin powder as a benchmark. The nine groups of aged powder were sintered with three different layer thicknesses (0.07 mm, 0.12 mm, and 0.15 mm), laser powers (65W, 70W, and 75W), and orientations (YZY 0⁰, YZY 90⁰, and XYY 0⁰). The selections of these laser power and layer thickness values for the sintering setting are due to machine and material parameter limitation. The results from these parameters then compared with those of the virgin powder, which sintered using the parameters provided by the manufacturer, in terms of powder morphology, mechanical properties, and tensile fracture behaviours. Observation made using scanning electron microscope (SEM) revealed that there were not many changes in shape, size, and distribution between the virgin and aged powder, but slightly larger sizes and the presence of cracks found in the aged powder. The tensile strength, elongation at break value, and Young’s modulus all shared a similar trend, increasing with higher laser power but decreasing with increased layer thickness. Regarding the fracture morphologies, the number of pores and dimples decreased with increased laser power but increased with thicker layer thickness. There was also the occurrence of un-molten powder, especially in specimens sintered at the YZY 90⁰ orientation with lower laser power and thicker layer thickness.

Study on the mechanical properties of layered gradient structure PBT-based flame retardant composite materials

Abstract To enhance the flame retardancy of Polybutylene Terephthalate (PBT) based composite materials and overcome the decrease in mechanical properties due to the high content of nano-antimony trioxide (nano-Sb2O3), this study initially applies a composite modification method to treat the surface of nano-Sb2O3. Subsequently, composite materials with a gradient distribution of nano-Sb2O3 are prepared through lamination hot-pressing technology, and their mechanical and flame retardant properties are investigated. The results show that the modifiers CTAB and KH560 are successfully grafted onto the surface of nano-Sb2O3, altering its surface properties. Through lamination hot-pressing technology, a gradient distribution from the surface to the core is achieved. Compared to the homogeneous distribution P666, G828 exhibits a 6% increase in Limiting Oxygen Index (LOI), improving the flame retardancy of the composite material. As nano-Sb2O3 enriches on the composite material's surface, the amount of char residue increases. The tensile strength, bending strength, and impact strength of G828 composite material increase by 19.7%, 37.1%, and 103%, respectively, compared to the homogeneous composite material P666, proving the significant effect of G828's gradient distribution in enhancing the mechanical properties of the composite material.

Non‐Destructive and Mechanical Characterization of the Bond Quality of Co‐Extruded Titanium‐Aluminum Profiles

The transportation industry aims to improve energy efficiency and reduce CO2 emissions, with a focus on reducing vehicle mass. A key method involves advanced lightweight construction techniques using materials like aluminum alloys. Research is concentrated on developing processes to combine different materials into reinforced hybrid components, such as aluminum and titanium. This study focuses on the lateral angular co‐extrusion (LACE) process to produce hybrid hollow profiles of EN AW‐6082 and Ti6Al4V, investigating the impact of the thermomechanical processing during extrusion and heat treatment (HT) on the resulting bond quality and material properties. Various HT routes are tested to see their impact on intermetallic phase formation, longitudinal weld seams, and bonding strength. Mechanical testing evaluates the tensile strength of the joining zone, while nondestructive ultrasonic testing (UT) assesses joining zone integrity and poor bonding detection. Results indicate that HT parameters significantly influence the bond quality and mechanical properties of hybrid profiles. UT data shows a strong correlation with tensile strength and intermetallic phase growth, providing a nondestructive way to evaluate bond quality. This study highlights the potential of LACE processes and optimized HT strategies to improve the performance and reliability of aluminum–titanium hybrid components.

Experimental Study on the Mechanical Properties of Sustainable Concrete using Recycled Plastic and Glass Waste

This study explores using recycled waste glass and plastic fibers as substitutes for fine aggregates in concrete to meet the growing need for sustainable building materials. The basic materials consist of OPC 43 grade and locally obtained river sand. The research incorporates glass powder from crushed beer bottles and plastic fibers from recycled plastic bottles into the concrete mixture. Various tests, including slump, compressive strength (CS), and split tensile strength (STS) assessments, are performed to ascertain the characteristics of the modified concrete in both its fresh and hardened states. The findings demonstrate a significant enhancement in the ease of handling when glass powder is used, exhibiting a surge of 170% and 270% for mixtures, including 15% and 25% glass powder, respectively, compared to conventional OPC concrete. Although including these recycled materials reduces compressive strength (19.95% for SP15 and 21.39% for SP25); tensile strength is significantly improved, with gains of 35% for SP15 and 53.75% for SP25. This research emphasizes the feasibility of integrating waste glass and plastic fibers into concrete as a practical method for sustainable building.

Enhancing green polyethylene composites with filler heat treatment: Pecan nutshells and Pinus sawdust impact

The aim of the present study was to produce sustainable composites using green low-density polyethylene (LDPE) reinforced with heat-treated lignocellulosic residues. The transformation processes were employed to enhance the chemical compatibility of lignocellulosic wastes with the polymer matrices of the composite materials. Sawdust from pine wood (PW) and milled pecan nutshells (NS) were subjected to a thermal treatment at 180°C for 2 h. These heat-treated residues were then homogenized with the polymer matrix and molded through hot compression. The resulting wood polymer composites (WPCs) were subjected to various characterization tests, including density, mechanical properties, infrared spectroscopy, thermal stability, hygroscopic behavior, and morphology. Comparing the composites, the inclusion of heat-treated fillers led to reductions in water absorption and thickness swelling, especially for the NS. Furthermore, the composites didn’t exhibit increased flexural strength and/or tensile strength after the bio-components treatment. The insertion of thermally treated lignocelluloses also resulted in slight decreases in equilibrium moisture content and apparent contact angles.

Damage evaluation in plain-woven CFRP plate with circular hole under cyclic tensile loading using electrical impedance tomography

Understanding and predicting damage progression within thin plain-woven carbon fiber-reinforced polymer (CFRP) components is an essential issue for scheduling maintenance intervals and structural inspections and typically requires extensive test series. However, uncertainties always remain and result in conservative design and unnecessary downtimes due to the repeated inspections of a healthy structure. Structural health monitoring (SHM) can be used to reduce these uncertainties, as it allows one to evaluate the condition of a mechanical structure during operation. Numerous SHM methods have been developed, which achieve different levels of damage identification but are often investigated at small coupons with nonrealistic structural damages and loading conditions on both structure and sensor. The present research investigates electrical impedance tomography (EIT) featuring an elastoresistive thin-film sensor to evaluate damage that propagates from a circular hole in a large plate under cyclic tensile–tensile multiblock loading. Applied fatigue loads were increased multiple times up to a total number of two million cycles. During the loading, damage initiated at the hole and continuously propagated into the plate. Repeated EIT evaluations of the applied sensor and validating evaluations by means of digital image correlation clearly revealed the robustness of the hardware and the potential of the SHM method for damage evaluation of plain-woven CFRP components.

Improvements to the bonding condition of ultra-thin concrete overlays for airport rigid pavements

ABSTRACT Ultra-thin concrete overlay (UTO) is an effective solution for repairing functional deficiencies in airport rigid pavements, with interface bonding properties critical to pavement performance and longevity. This study systematically investigates methods to enhance UTO interface bond strength under heavy dynamic loads. Aircraft dynamic simulations were performed to analyze stress states during landing, taxiing, and turning, identifying the required ultimate bond strength to prevent interface failure. Laboratory tests measured the shear and pull-out strengths of new and old concrete interfaces. A styrene–butadiene rubber (SBR) modified cement quartz mortar adhesive was developed with optimal curing conditions, and the effects of grooving intervals on bonding strength were assessed. Results demonstrated that the interface treatment increased the safety factor for tensile failure from 0.69 to 1.25 and for shear resistance from 0.61 to 1.12 under dynamic loads. This research provides a scientific basis for enhancing UTO applications in the functional rehabilitation of airport rigid pavements, offering a practical solution to improve safety and durability in high-stress environments.

Novel antimicrobial biodegradable composite films as packaging materials based on shellac/chitosan, and ZnAl2O4 or CuAl2O4 spinel nanoparticles.

ZnAl2O4 and CuAl2O4 spinel nanoparticles were prepared by a modified Pechini method and used with the natural chitosan (CS) and shellac (SH) polymers to form novel composite membranes as promising food packaging materials. The selection of ZnAl2O4 and CuAl2O4spinel nanoparticles was based on their antibacterial characteristics, availability, and economy. Using a straightforward and adaptable solution mixing and casting method, the bio-composites were created. The mechanical, physical, antibacterial, homogeneity and air permeability properties of composite films were investigated. The film structure was evaluated in terms of component interactions using FTIR spectra. The addition of 10% SH increased the tensile strength, percentage strain at maximum load, Young's modulus, and burst strength by 114-101%, 3.6-8.4, 103-119, and 179-153% for low and middle M.wt./CS respectively. Chitosan/shellac-CuAl2O4composite has superior properties compared to ZnAl2O4composite. In general, 0.05% spinel provides a composite having better qualities than that of 0.1 additions. Middle M.wt. chitosan provides a composite with superior properties compared to that of low M.wt. The incorporation of ZnAl2O4 or CuAl2O4 enhanced the thermal stability of the SH/CS composite. ZnAl2O4 provides superior thermal stability than CuAl2O4. When shellac/CS film structure is treated with the previously indicated ZnAl2O4 or CuAl2O4 formulation, the % swelling decreases along with an increasing in the gel fraction. The antimicrobial assessment using inhibition zone diameter and shake flask methods showed that a composite of 1:9 shellac/chitosan/0.05% of CuAl2O4 exerted the highest Gram-positive antibacterial activity against B. mycoides (21mm), and C. albicans (22mm). So, these enhancements make chitosan/shellac/ZnAl2O4 or CuAl2O4composite films a good alternative to producing food packaging materials.

A review of graphene biopolymer composite in piezoelectric sensor applications

Abstract The amazing electrical, optical, mechanical and thermal properties combined with high specific surface area of graphene making it as an appealing integrant for stimuli responsive high performance smart materials. Typical graphene-based smart materials encompass mechanically exfoliated perfect graphene, chemical vapor deposited first-class graphene, chemically moded graphene including graphene oxide and reduced graphene oxide and their macroscopic assemblies or composites. The ability of these graphene-based materials ending up interacting with biopolymers to come up with quite fascinating electrical, mechanical, optical, thermal and sensing characteristics has have attracted a considerable number of attentions. The biggest advantage of using biopolymer-based materials is non-corrosiveness, ease in coloration, good tensile strength, and biodegradability but are abided by drawback of the poor mechanical strength, lack of response, and unstable environmental stability. However, graphene incorporated biopolymers provided beneficent attributes for example ability to detect various forms of stimuli such as gaseous molecules include biomolecules, pH value, mechanical flexibility, electrical and thermal conductivity to enable ongoing promising advancement of the piezoelectric sensor applications. This review explores the piezoelectric development based on several graphene fabricated biopolymer composite and it is use in healthcare monitoring, structural health monitoring, industrial process monitoring, consumer electronics applications. Furthermore, we enlighten the challenges and future perspectives of graphene biopolymer piezoelectric sensors.

Modification of Poly(3-Hydroxybutyrate) with a Linear Polyurethane Modifier and Organic Nanofiller—Preparation and Structure–Property Relationship

The growing demand for products made of polymeric materials, including the commonly used polypropylene (PP), is accompanied by the problem of storing and disposing of non-biodegradable waste, increasing greenhouse gas emissions, climate change and the creation of toxic products that constitute a health hazard of all living organisms. Moreover, most of the synthetic polymers used are made from petrochemical feedstocks from non-renewable resources. The use of petrochemical raw materials also causes degradation of the natural environment. A potential solution to these problems is the use of biopolymers. Biopolymers include biodegradable or biosynthesizable polymers, i.e., obtained from renewable sources or produced synthetically but from raw materials of natural origin. One of them is the poly(3-hydroxybutyrate) (P3HB) biopolymer, whose properties are comparable to PP. Unfortunately, it is necessary to modify its properties to improve its processing and operational properties. In the work, hybrid polymer nanobiocomposites based on P3HB, with the addition of chain, uncross-linked polyurethane (PU) and layered aluminosilicate modified with organic salts (Cloisite®30B) were produced by extrusion process. The introduction of PU and Cloisite®30B to the polymer matrix (P3HB) influenced the processing parameters beneficially and resulted in a decrease in the extrusion temperature of more than 10 °C. The influence of the simultaneous addition of a constant amount of PU (10 m/m%) and the different amounts of nanoadditives (1, 2 and 3 m/m%) on the compatibility, morphology and static mechanical properties of the resulted nanobiocomposites were examined. The component interactions by Fourier transformation infrared spectroscopy (FTIR) analysis, nano- and microscale structure studies using small-angle X-ray scattering (SAXS) and morphology by scanning electron microscopy (SEM) were carried out, and the hardness and tensile strength of the obtained polymer nanobiocomposites were determined. FTIR analysis identified the compatibility of the polyester matrix, PU, and organomodified montmorillonite, the greatest being 3 m/m% Cloisite30B content. The addition of PU to the polyester elasticizes the material and decreases the material’s strength and ductility. The presence of nanoclay enhanced the mechanical properties of nanobiocomposites. The resulting nanobiocomposites can be used in the production of short-life materials applied in gardening or agriculture.

Preparation and performance study of heparinized multi‐walled carbon nanotube/cellulose acetate hemodialysis membrane

AbstractCurrently, the incidence of kidney failure is increasing worldwide. Hemodialysis is the main method for the treatment of kidney diseases, and the continuous development of new hemodialysis membranes is the key to improve the treatment effect and the quality of life of patients. In this study, heparinized multi‐walled carbon nanotube/cellulose acetate (Hep/MWCNTs@CA) membranes were prepared by non‐solvent induced phase separation (NIPS). The morphology and pore structure of Hep/MWCNTs@CA membranes were characterized by scanning electron microscopy (SEM). The elongation at break and tensile strength of the membranes were characterized by a mechanical property universal tester. The results showed that mechanical properties of 0.1 wt% MWCNTs enhanced the membrane is best. The water contact angle test confirmed that MWCNTs can improve the membrane hydrophilicity, and combined with the adsorption test results for proteins, it was found that the hydrophilicity can reduce the adsorption of proteins to the composite membrane and improve the blood compatibility of the material. The dialysis performance of urea and lysozyme was tested by a self‐made simulated hemodialysis device, and the clearance rates of urea and lysozyme were 84% and 47.2%, respectively, which showed that the interfacial gap between MWCNTs and CA matrix can make the composite membrane retain a high retention rate of macromolecular proteins (92.3%) and further improved the clearance rate of small and medium molecular toxins. In addition, the good blood compatibility and biocompatible properties of the materials were confirmed by hemolysis, recalcification and cytotoxicity tests on Hep/MWCNTs@CA membranes. In conclusion, the prepared Hep/MWCNTs@CA holds great potential for application in the field of hemodialysis.

Investigation of mechanical, electrical conductivity, wear and corrosion performances of traditional CuNi2Si and new high performance CuNiCoSi copper based alloys

ABSTRACT CuNi2Si copper alloy has been utilised in electronics, resistance welding electrodes, and electrical connections. The industry is seeking new copper alloys with improved strength and electrical conductivity. Cu-Ni-Co-Si alloys have been designated as the next generation of high-performance copper alloys. In this study, the cast and hot-forged CuNi2Si and CuNiCoSi alloys were solid-solution treated and aged. Under optimum ageing conditions, alloys were tested for hardness, electrical conductivity, microstructure, mechanical properties, wear resistance, and corrosion resistance. Comparing the CuNiCoSi alloy to the Co-free CuNi2Si alloy, the Co element decreased grain size, accelerating Ni2Si and Co2Si precipitates. The CuNiCoSi alloy has 23% higher conductivity, 31% higher tensile strength, and 17% higher resistance under a 5 N load, 44% higher under a 10 N pressure, and 50% higher under a 20 N load in wear tests than the CuNi2Si alloy. Potentiodynamic studies showed that the CuNi2Si alloy removed 40% more metal per unit time than the CuNiCoSi alloy. The CuNiCoSi alloy outperforms the CuNi2Si alloy in hardness, conductivity, mechanical strength, wear resistance, and corrosion resistance. Due to its outstanding performance, the CuNiCoSi alloy will be vital in industrial equipment, aviation, space, nuclear energy, and electrical power generation.

Redispersible Acrylic Ester Polymers: Effect of Polymer Property Changes Due to Polymerization Method Modification and Functional Additives on the Performance of Polymer Cement Mortar

This paper presents an experimental study aimed at improving the performance of polymer cement mortar by evaluating the properties of acrylic ester redispersible polymers, synthesized using a change in polymerization method from emulsion monomer to monomer dropwise addition methods, along with the use of a functional additive in the form of a foaming agent. To achieve the research objectives, a polymer with a glass transition temperature of −11 °C was synthesized by fixing the monomer ratio, particle-size distribution, and glass transition temperature, and the physical properties of the polymer cement mortar were assessed. The results showed that polymers synthesized using the modified polymerization method increased elongation at break and possessed a 35% smaller average particle size. The use of the foaming agent also resulted in enhanced tensile strength. The polymer cement mortars made with these respective polymers demonstrated improvements in compressive strength 11~25%, flexural strength 53~77%, bond strength 78~113%, volumetric changes 65~88%, and water absorption 30~70%. These findings suggest that changes in the polymerization method and the incorporation of functional additives influence the average particle size and air entrainment control properties of the polymers, thereby positively impacting the performance of the cement hydrates.

Development and Characterization of Mikania, Kapok, Wool, Sugarcane, and Pineapple Fiber Reinforced Polyester Composite

ABSTRACTThis study utilizes plant‐derived fibers including Mikania, wool, kapok, sugarcane, and pineapple as strengthening additions to fabricated and tested reinforced polyester mixtures. This study aimed to examine the mechanical qualities and potential applications of these natural materials in boosting the effectiveness of polyester composites. The composites were formed by including natural fibers into a polyester base using a hand lay‐up preparation method. The finished samples received a complete assessment, covering tensile and impact testing as well as SEM analysis. The findings showed that incorporating natural materials like Mikania vines, wool, kapok fuzz, sugarcane fibers, and pineapple leaves had a notably positive effect on the mechanical features of the plastic composites. The tensile strength of the material combined pineapple was particularly high, achieving a maximum stress of 42.4822 N/mm2 and a maximum stretch of 4.27950%. Similarly, that same composite exhibited a maximum stretch of 3.75753% and a maximum stress of 77.4922 N/mm2 during the bending experiment. The substances exhibiting the strongest impact endurance, as determined by the impact assessment, included kapok, Mikania, wool, pineapple, and sugarcane. The kapok provided an impact toughness of 1.2 N m, which was somewhat elevated. This research offers a precious understanding of using natural fibers as strengthening additives in polyester composites, demonstrating their flexible perspective for many uses. The discoveries present hopeful possibilities for additional examination and progression in composite materials, consequently advancing the development of sustainable materials.

Effect of Dual Curing Agent (TDI:DDI) on the Mechanical Properties and Burning Rate of HTPB-Based Solid Propellant

ABSTRACT In this study, the effect of dual curing agent (toluene diisocyanate:dimeryl diisocyanate (TDI:DDI)) on the properties of hydroxyl-terminated polybutadiene (HTPB)-based solid propellant (such as mechanical strength, elongation percentage, elastic modulus, hardness, burning rate and pressure exponent (n)) has been investigated. Thus, five solid propellant formulations with different proportional amounts of TDI and DDI, with same loading rate and constant R value, were prepared, and the mechanical properties and burning rate of the prepared samples were evaluated. Tensile test conducted on the solid propellant cured for 7 days showed that increasing the proportional amount of DDI compared to TDI in the solid propellant formulation increases the elongation percentage and decreases the tensile strength, modulus, burning rate and pressure exponent (n). Considering that DDI also plays the role of a softening agent in the solid propellant formulation, increasing its amount in the solid propellant formulation will decrease the viscosity, causing a higher pot life.