International Journal of Lightweight Materials and Manufacture最新文献

The lightweight elastomers (such as nitrile rubber) frequently used in the Positive Displacement Motor (PDM) stator assembly are subjected to harsh environmental conditions. These elastomeric components are manufactured by primary casting/shaping methods, followed by secondary manufacturing/machining processes. The production of intricate shapes/sizes in single or batch-size elastomeric components using primary casting methods requires a customized mould to fulfil the requirement of sudden breakdown conditions, which is uneconomical. It necessitates an alternate production method that can satisfy the need for the elastomeric component at the stage of failure. The current research focuses on the possibility of producing nitrile rubber components using a non-conventional machining method, Suspension-type Abrasive Water Jet Machining (AWJM), suitable for batch production with better dimensional stability and versatility in shape/size. This work presents the experimental investigation of Suspension-type AWJM of nitrile rubber specimens (15 mm thick) using a custom-designed Tungsten Carbide (WC) nozzle under room-temperature condition. The top surface of the machined slot is analyzed to determine the mineral composition and abrasive particle embedding through Energy Dispersive Spectroscopy (EDX) and Backscatter Electron (BSE) detector. The Taguchi Orthogonal Array (OA) is employed to study the effect of the process parameters (Water Jet Pressure (WJP), Traverse rate (V_f), and Stand-Off Distance (SOD)) on the performance parameters (Kerf Taper Ratio (KT_R), and Material Removal Rate (MRR)). The Analysis of Variance (ANOVA) is applied to check the statistical significance and percentage contribution of each process parameter on the performance of Suspension-type AWJM. The uniformity in the geometry of the machined slot is analyzed by the waviness patterns observed in the profile images of the cut specimen. The analysis of the EDX results reveals the presence of Manganese (Mn) and an increased percentage of Silicon (Si) particles near the top surface of the machined slot. The SOD influences KT_R the most, whereas V_f highly influences MRR. It is observed that the waviness pattern is minimal at high WJP experimental runs. The outcome of this research work provides a quick and economical method of producing the PDM bushings instead of the casting/moulding method.

Novel hybrid laminates consisting of carbon fiber-reinforced polymers and steel plate cold commercial (CFRP-SPCC) have been successfully manufactured and tested in the present study. Four different tests have been made i.e., tensile test, flexural test, double cantilever beam (DCB) or Mode I test, and end notched flexure (ENF) or Mode II test. After being tested, these samples need to be evaluated. Hence, an inappropriate evaluation step while identifying the cause of failure of the failed specimens can create a false conclusion. The present study aims to systematically evaluate the fractured specimens of CFRP-SPCC in different tests (tensile, flexural, DCB, and ENF test) using different tools, i.e., pocket camera, digital microscope, light microscope, and Scanning Electron Microscopy (SEM). The results showed, in terms of tensile, the highest strength occurred with 1475.4 MPa. In comparison, the highest flexural strength occurred with 1516.1 MPa, while DCB and ENF showed the highest values with 116.4 and 330 J/m², respectively. Furthermore, the results showed that digital and light microscopes are satisfied to evaluate the specimen in tensile test. However, for the flexural test, ENF, and DCB test, besides the light microscope, further analysis using SEM-EDX is recommended to evaluate the specimen after failure.

An experimental study has been performed to investigate the coupled effects of hydrostatic deep depth pressure and sustained salt-water immersion on the mechanical properties and material structure of additively manufactured (AM) polymer based materials. The materials that were evaluated in the study were produced by both the material extrusion and vat photopolymerization printing methods. The material extrusion materials consisted of Stratasys ULTEM 9085 and Markforged Onyx and the vat photopolymerization material was Accura ClearVue resin. Water immersion was conducted with 3.5% NaCl solution at room temperature under a pressure of 34.5 MPa in a novel test facility for long duration, high pressure water saturation. The respective materials were characterized in three conditions: (1) baseline with no water saturation, (2) 30 day water immersion, and (3) 60 day water immersion. The change in mechanical properties as a function of aging time was quantified through controlled laboratory testing, namely tension, compression, flexure, and in-plane fracture toughness. Additionally, a microscopic evaluation was performed to evaluate the physical material degradation between layer bonding due to the saline water absorption. The significant findings of the study highlight that salt water immersion has differing effects on additively manufactured materials based on the material composition of the base material and thus significant consideration must be given to material selection in marine environments.

The main factors in the ballistic impact mechanism, an incredibly complicated mechanical process, are the target material's thickness, toughness, strength, ductility, density, and projectile parameters. Creating resilient, high-strength, and high-modulus fibers has made it possible to use natural fibers and their composite laminates for various impact-related applications today. Kinetic energy absorption, penetration depth, and residual velocity were the parameters affecting the performance of natural fiber composites used in the armor systems. This review aims to comprehend the several influencing factors that significantly impact the target's ballistic impact performance. In addition to experimental study efforts, many analytical, numerical modeling, and empirical technique-based research approaches have also been considered while analyzing the various components. The paper also examines several factors that determine how well natural fiber composite functions, including internal factors like material composition, characteristics of matrix and reinforcement, the kind and choice of fiber/matrix, failure modes, impact energy absorption, and external factors such as residual velocity, and various projectile nose angles. It also emphasizes the ways to improve composites for high performance and ballistic efficiency, as well as the economic cost analysis of switching out synthetic fibers for natural ones in a ballistic composite.

Double-pass friction stir processing (FSP) engendered intense plastic deformation in Mg–3Al–1Zn alloy with variation in the most influential process parameters, namely tool rotation speed and tool traverse speed. The effect of change in the FSP processing route on the resulting grain size was also analysed. Uniformly distributed fine equiaxed grains (average grain size ∼ 6.15 μm) were acquired in the stir-zone (SZ) due to extensive dynamic recrystallization (DRX). Attainment of large grain refinement encouraged for further investigation of the alloy's superplastic behaviour at elevated temperatures. Microstructural examination was followed by uniaxial tensile tests that were carried out at three distinct temperatures of 350, 400 and 450 °C at the constant strain rate of 1.3 × 10⁻³ s⁻¹. With the rising deformation temperature, reduction in the flow stress led to significant increase in the tensile elongations of all the processed specimens. Micro-grain superplasticity (elongation >200% under tension) was observed at the highest deformation temperature for the friction stirred specimen with the finest grains.

With the growing concern about climate issues and the urgent need to reduce carbon emissions, hydrogen has attracted increasing attention as a clean and renewable vehicle energy source. However, the storage of flammable hydrogen gas is a major challenge, and it restricts the commercialisation of fuel cell electric vehicles (FCEVs). This paper provides a comprehensive review of common on-board hydrogen storage tanks, possible failure mechanisms and typical manufacturing methods as well as their future development trends. There are generally five types of hydrogen tanks according to different materials used, with only Type III (metallic liner wrapped with composite) and Type IV (polymeric liner wrapped with composite) tanks being used for vehicles. The metallic liner of Type III tank is generally made from aluminium alloys and the associated common manufacturing methods such as roll forming, deep drawing and ironing, and backward extrusion are reviewed and compared. In particular, backward extrusion is a method that can produce near net-shape cylindrical liners without the requirement of welding, and its tool designs and the microstructural evolution of aluminium alloys during the process are analysed. With the improvement and innovation on extrusion tool designs, the extrusion force, which is one of the most demanding issues in the process, can be reduced significantly. As a result, larger liners can be produced using currently available equipment at a lower cost.

The enormous composition possibilities and the potential of developing alloys with improved properties have resulted in a spike in research interest in the area of high entropy alloys (HEAs) since 2010. Being multicomponent alloys with five or more metallic elements mixed in equimolar or non-equimolar ratio, HEAs offer limitless possibilities in the development of new alloys with unique properties as compared to the conventional alloys development techniques that involve the addition of one or more alloying elements in minute quantity to the principal element. Despite the tremendous interest in the field of HEAs and the development of new HEAs with unique properties, a comprehensive review of the effects of fabrication techniques on the mechanical properties of the developed alloys is still limited in the open literature. Hence, an attempt was made in this review to show the different techniques used in the manufacturing and synthesizing of HEAs and the effects of the used techniques on the mechanical properties of the alloys. Finally, some of the major challenges associated with the manufacturing and synthesizing of HEAs are reported.

Large amount of wood dust is created as a byproduct of woodworking activities. Every year, there is an increase in wood dust generation, which severely pollutes the environment. Consequently, it becomes imperative to use wood dust in the production of useful products. A Carbonized Wood-Silicon Dioxide Filled Natural Rubber Composite (CWSDFNRC) was therefore created in this work using a compression molding method. The friction and compression properties of the composites were determined. Modeling of the composite's mechanical and friction characteristics was done using artificially intelligent techniques including Response Surface Methodology (RSM), Artificial Neural Network (ANN), and Adaptive Neuro-Fuzzy Inference System (ANFIS). The novel material was thermally analyzed using Dynamic Mechanical Analysis (DMA), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), and Differential Thermal Analysis (DTA). The effectiveness of RSM, ANN, and ANFIS was demonstrated by relevant error indices. The optimization method revealed the ideal level of fitness at particle size, carbonization temperature, filler content, curing temperature, curing pressure, and curing time of 150 μm, 214 °C, 51 phr, 150 °C, 3 Pa, and 10 min respectively. These fitness conditions gave an optimal value of 17.63 MPa for compressive strength and a friction coefficient of 0.96. The novel material's characteristics contrasted well with those of comparable materials described in the literature, suggesting that it has the potential to be used in the manufacture of outer shoe soles and other elastomeric applications.

Distinct alloys have different chemical and thermal characteristics, making it difficult to weld together. For the purpose of maximizing tensile strength and weld hardness of the joint, the gas metal arc (GMA) welding process for the dissimilar aluminium alloys AA5083-O and AA6061-T6 was modelled and optimized in the current study. A genetic-neural approach was attempted, in which optimal artificial neural network (ANN) was applied to model the process and genetic algorithm (GA) approach was extended to optimize the parameters. The proposed genetic-neural (GA-ANN) approach was also compared to the traditional response surface methodology (RSM). In predicting the reactions of a GMA welded joint made of two different alloys, AA5083-O and AA6061-T6, the suggested optimum ANN model was shown to be more accurate (error 6%). The genetic-neural optimization technique has less inaccuracy (approximately 5% error) than the RSM optimization approach, however the more computational time was required to select GA-ANN parameters.

The ultrasonic spot welding (USW) is used to develop the lap joints of AA 6061-T6 aluminium alloy because it is difficult to spot weld using resistance spot welding (RSW) and laser beam spot welding (LBSW) processes due to its high electrical conductivity, thermal conductivity and light reflectivity respectively. The main objective of this investigation is to optimize the USW parameters specifically welding time (s), amplitude (%) and pressure (bar) for enhancing the tensile shear fracture load (TSFL) bearing capability of AA 6061-T6 aluminium alloy lap joints for automotive applications. The statistical response surface methodology (RSM) was utilized for generating strength prediction models (SPM) and validated using analysis of variance (ANOVA). The RSM is widely used for optimizing the process parameters as it provides greater information such as optimum conditions, direct effect of process parameters and performance prediction from limited number of experiments compared to other optimization techniques. The response surfaces were created using RSM and analyzed. The effect of USW parameters on macrostructure, microstructure and TSFL of USW joints was studied. From the results, it was observed that the USW joints created using the welding amplitude of 100%, welding time of 21 s and welding pressure of 6 bar exhibited greater TSFL capacity of 5.08 kN. The SPM accurately predicted the TSFL of USW joints within 5% error on 95% confidence. Welding pressure disclosed major effect on TSFL of USW joints followed by welding amplitude and time. The greater TSFL of USW joints is imputed to the better coalescence of weld surfaces and refined microstructure.