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The use of laboratory testing has become more significant to assess abrasion resistance in flexible reinforcement of armour and car structural components. In this study, compliant composite with constituents as woven jute fabric and natural rubber encapsulated in an NR-based B stage cured prepreg were tested for wear due to abrasion under two- and three-body conditions. Flexible composites are fabricated in three different configurations namely Jute/Rubber/Jute, Jute/Rubber/Rubber/Jute and Jute/Rubber/Jute/Rubber/Jute. The present study makes use of abrasive paper with a grit size of 60 and silica sand with size 250 μm as the abrasive medium for two- and three-body abrasion tests, respectively, and the specific rate of wear is calculated. Though the wear trend of the composites follows a similar pattern in the case of two- and three-body wear, the mechanisms governing the wear are found to be different. The morphology of the worn surface is studied with the aid of a scanning electron microscope. [ABSTRACT FROM AUTHOR]

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Determining the interlaminar shear strength (ILSS) of the composite laminates is vital for deciding their usage in any engineering applications. The matrix used and its curing characteristics are vital in deciding the ILSS of the composite. Present work deals with an experimental study on adhesive behavior, degree of flexibility, ILSS, and damage mechanism of the novel jute/rubber-based flexible "green" composite. The proposed flexible composites were prepared in three different stacking sequences, namely jute/rubber/jute (JRJ), jute/rubber/rubber/jute (JRRJ), and jute/rubber/jute/rubber/jute (JRJRJ), using compression molding technique. After determining the optimal curing characteristics of the proposed rubber-based matrix, the constituents are tested for their adhesive strength with the matrix which showed that rubber matrix system is compatible with jute fabric and natural rubber sheet. Composites are prepared and degree of flexibility for each stacking sequence is found out. Results pertaining to ILSS show that JRJRJ has better ILSS compared to JRJ and JRRJ. Fractographic analysis using scanning electron microscope reveals the mode of failure of the composites and the mechanism governing their failure. Fourier transform infrared spectroscopic study reveals the bonding between the constituents is good enough to be used in composites with flexibility. [ABSTRACT FROM AUTHOR]

Determining the resistance to abrasion of the flexible cladding for armours and automobile structural components with the aid of lab scale tests has become increasingly important. In the present study, three body wear behaviour of flexible green composites comprising of jute in woven fabric form with interleaved natural rubber sheets bonded through rubberized B stage cured Pre pegs have been studied. Flexible composites are fabricated in three different configurations having different layers of jute and rubber. The present study makes use of silica sand as the abrasive medium. The specific wear rate along with loss in mass and volume of the composite due to wear is determined and it was found that specific wear rate is dependant of the sliding distance. Comparing the specific wear rate of all the three stacking sequences, it was found that JRJ stacking sequence provides better wear resistance. Compliant and tough nature of the rubber makes it hard to wear it out through tearing action and also the wear resistance of flexible composites is enhanced with inclusion of rubber. Mechanism of wear in each of the constituent used is studied. The present study serves as a benchmark work for the future research in this area. [ABSTRACT FROM AUTHOR]

The development of natural fiber-reinforced polymer composites is becoming prominent in numerous engineering applications over the synthetic fiber-reinforced composites mainly because of their environment-friendly characteristics. This article deals with comparative study on selection of optimal stacking sequence (jute/rubber/jute (JRJ), jute/rubber/rubber/jute, and jute/rubber/jute/rubber/jute) of the jute/natural rubber-based completely biodegradable flexible composite using multi-attribute decision making (MADM) approaches namely hybrid entropy-VIse Kriterijumska Optimizacija kompromisno Resenja (VIKOR) and preference selection index (PSI) methods. Tensile strength, tear strength, specific impact strength, and specific wear rate are used as attributes for MADM methods. The results show good agreement between hybrid entropy-VIKOR and PSI methods used for stacking sequence selection. Scanning electron microscope analysis is carried out to study the failure mechanisms of the proposed flexible composite. The findings of the present study led to the choice of JRJ as the preferred stacking sequence among all the three stacking sequences considered as it exhibited the best overall properties compared to other two configurations of the flexible composite. [ABSTRACT FROM AUTHOR]

The present study deals with development of conceptual proof for jute rubber based flexible composite block to completely arrest the projectile impacting the target at high velocity impact of 400 m/s through numerical simulation approach using finite element (FE) method. The proposed flexible composite blocks of repeating jute/rubber/jute (JRJ) units are modelled with varying thickness from 30 mm to 120 mm in increments of 30 mm and impacted by flat (F), ogival (O) and hemispherical (HS) shaped projectiles. All the considered projectiles are impacted with proposed flexible composite blocks of different thicknesses and the penetration behaviour of the projectile in each case is studied. The penetration depth of the projectile in case of partially penetrated cases are considered and the effect of thickness and projectile shape on percentage of penetration depth is statistically analyzed using Taguchi's design of experiments (DOE). Results reveal that the though proposed flexible composite block with thickness of 90 mm is just sufficient to arrest the complete penetration of the projectile, considering the safety issues, it is recommended to use the flexible composite with thickness of 120 mm. The nature of damage caused by the projectile in the flexible composite is also studied. Statistical studies show that thickness of the block plays a prominent role in determining the damage resistance of the flexible composite. [ABSTRACT FROM AUTHOR]

The present study deals with the experimental, finite element (FE) and analytical assessment of low ballistic impact response of proposed flexible 'green' composite make use of naturally available jute and rubber as the constituents of the composite with stacking sequences namely jute/rubber/jute (JRJ), jute/rubber/rubber/jute (JRRJ) and jute/rubber/jute/rubber/jute (JRJRJ). Ballistic impact tests were carried out by firing a conical projectile using a gas gun apparatus at lower range of ballistic impact regime. The ballistic impact response of the proposed flexible composites are assesses based on energy absorption and damage mechanism. Results revealed that inclusion of natural rubber aids in better energy absorption and mitigating the failure of the proposed composite. Among the three different stacking sequences of flexible composites considered, JRJRJ provides better ballistic performance compared to its counterparts. The damage study reveals that the main mechanism of failure involved in flexible composites is matrix tearing as opposed to matrix cracking in stiff composites indicating that the proposed flexible composites are free from catastrophic failure. Results obtained from experimental, FE and analytical approach pertaining to energy absorption and damage mechanism agree well with each other. The proposed flexible composites due to their exhibited energy absorption capabilities and damage mechanism are best suited as claddings for structural application subjected to impact with an aim of protecting the main structural component from being failed catastrophically. [ABSTRACT FROM AUTHOR]

Polymer based natural fiber reinforced composites are finding their applications in almost all fields of engineering. Flexible composites are different class of composite materials finding their usage in secondary structural application such as sacrificial structures like claddings. Mechanical and tribological characterization of the newly developed composites becomes important prior to using them in any engineering application. The present study concentrates on evaluating the tensile and slurry erosive behaviour of flexible composite manufactured by reinforcing naturally available jute fiber in the form of woven fabric in the naturally available sun dried rubber sheets (NR) using compression moulding technique. ASTM D412 standard is used to evaluate the tensile properties of the proposed flexible composite and the NR sheets. The slurry erosive behaviour is assessed using Ducom slurry erosion testing machine. The results reveal that reinforcing jute with natural rubber enhances the tensile strength compared to natural rubber sheet and the wear of the proposed flexible composite is minimal due to inclusion of natural rubber which is elastic in nature. [ABSTRACT FROM AUTHOR]

In the present study, the emphasis is on analysing the slurry erosive behaviour of novel green flexible composite made from jute fiber and natural rubber of ribbed smoke sheet (RSS) grade. The bonding gum made of natural rubber is used to bind the fiber and RSS rubber. Three different stacking sequences namely jute-rubber-jute (JRJ), jute-rubber-rubberjute (JRRJ) and jute-rubber-jute-rubber-jute (JRJRJ) are considered. Erosive studies are carried out on the prepared composites under three different rotation speeds (500, 1000 and 1500 rpm) and three different sand concentration (50, 75 and 100 gms) with silica sand as the abrasive medium dispersed in tap water. Design of experiments (DOE) is carried out using Taguchi's L9 orthogonal array on slurry erosion test to find out the effect of the stacking sequence, rotation speed and sand concentration on the weight loss of the composite. Through ANOVA, it was concluded that sand concentration is the main factor affecting the weight loss of composite. Regression model is developed and it was found that the developed model is adequate and feasible to predict the weight loss due to slurry erosion within the range of experimental conditions. [ABSTRACT FROM AUTHOR]

The present study deals with the experimental approach of finding the ballistic limit of neat jute fabric along with its compliant composite, compliant hybrid composite with and without interleaved natural rubber (NR) sheets and stiff jute epoxy (JE) composite. Mechanism governing the damage in the proposed targets are studied. Ballistic impact tests were carried out by firing a conical projectile using a gas gun apparatus at lower range of ballistic impact regime. The ballistic impact response of the neat jute fabrics along with proposed compliant composites are assessed based on energy absorption and damage mechanism. Results revealed that the complaint hybrid composites exhibit enhanced ballistic response compared to neat jute fabrics, compliant and stiff composites. Inclusion of NR aids affects the ballistic performance of the composite significantly by keeping the composite flexibility. Rubber does not restrict the yarns through which the whole fabric resists against projectile energy. This behavior is contrary to the epoxy matrix, in which only a few yarns in impact zone resist. This difference significantly changes the ballistic performance of stiff composite and compliant hybrid composite. The damage study reveals the various mechanisms responsible for failure in neat fabrics, compliant composites, compliant hybrid composites and stiff composites. Compliant hybrid composites fail due to matrix tearing as opposed to matrix cracking in stiff JE composites indicating that the proposed complaint composites are free from catastrophic failure. Thus, the proposed compliant hybrid composites are best suited for ballistic applications. • In the present study, the emphasis is on analyzing the lower ballistic impact response of neat natural fabrics and their compliant and stiff composites. • The mechanisms involved in energy absorption and damage of the neat fabrics and composites are discussed. • The compliant composite is developed using naturally available materials. [ABSTRACT FROM AUTHOR]

This paper presents an experimental investigation on low velocity impact (LVI) behaviour of flexible biocomposite laminates with different stacking sequence namely jute/rubber/jute (JRJ), jute/rubber/rubber/jute (JRRJ), jute/rubber/jute/rubber/jute (JRJRJ) and subjected to different impact energy levels using a conical shaped impactor. The performances of the proposed flexible composites are evaluated based on their energy absorption, peak force, coefficient of restitution (CoR), energy loss percentage (ELP) and failure behavior. Results indicated that JRJ provides better energy absorption and JRJRJ provides better damage resistance when subjected to LVI. Microscopic analysis revealed that the flexible composites fail mainly due to the tearing mechanism of the matrix as opposed to cracking in case of conventional stiff composites. It was also found that flexible composites are free from delamination. Compared to conventional stiff composites, there is no catastrophic failure observed in the proposed flexible composite. The overall performance evaluation of these proposed flexible composites indicates that these flexible composites can be potential sacrificial materials such as claddings used to protect primary structural components subjected to LVI. The systematic methodology employed in the present study serves as a benchmark for the effective utilization and selection of flexible composites for LVI applications. [ABSTRACT FROM AUTHOR]