The push-off phase is a critical part of initiating movement during walking, and it requires a significant amount of energy. Recent research has shown that the passive use of springs in parallel with the leg can harvest the push-off energy and reduce the total metabolic energy of walking for healthy subjects. In this study, we present the design of a prosthetic leg with a passive-based mechanism to reduce walking energy consumption for above-knee amputees. The mechanism stores energy during the stance phase of the gait cycle and releases it to support the prosthetic leg during locomotion. The known polycentric knee joint 3R36 and the ankle-foot joint ESAR were chosen and adopted for this study. We also utilized a ratchet clutch that connects with a spring and rope from the pylon to the foot which regulates movement and saves energy. Our simulations demonstrate that the spring stores elastic energy from approximately 22% of the gait cycle and reaches its maximum energy storage at approximately 50% of the walking cycle. The energy is then released at approximately 58% of the stride cycle during the push-off phase. The motion of the proposed prosthetic leg for individuals with transfemoral amputations mimics the normal walking pattern of healthy individuals well.

Using the assumption that the load is evenly distributed in the horizontal direction, the article has given the cable deflection equation as a function that depends only on the horizontal coordinates, the length of the cable and horizontal distance between two supports. This result leads to the construction of a general system of equations to calculate the deflection, tension, and elongation of an elastic single cable resting on two supports with or without high difference, bearing uniformly distributed loads (or evenly distributed at intervals) and load is concentrated at many points. Calculations of examples to compare with results have been performed by other methods.

A lack of natural aggregates in the future is unavoidable, which generates issues for building development. For many industries, natural resources constitute a significant source of revenue. As a result, light artificial aggregate is produced to anticipate the decreasing source of natural aggregate. Production of artificial geopolymer aggregates, fly ash from the burning of coal has been proposed. This paper investigates the optimal proportion of epoxy resin and coal fly ash-based synthetic aggregates. The artificial aggregates are produced following specific gravity and compressive strength standards that may be used as a component of lightweight structural concrete (LWC). The production polymer lightweight aggregate (PLA) comes from a combination of coal fly ash and epoxy resin. The results show that PLA 50:50 to PLA 74:26 can be used for 6 hours to make structural concrete with a strength of more than 17 MPa. PLA 80:20 could achieve compressive strength with the range of 7-17 MPa. PLA 84:16 achieves a compressive strength range of 0.35 to 7 MPa and is utilized as a non-structural element. However, the flexural strength values in concrete LWC 70:30 and LWC 80:20 are higher, at 46.1% and 7.63%, respectively.

In this paper, Finite Element Analysis was used to simulate ship hatch covers with different grid geometries viz. Square grid, Inclined grid, Diamond grid and Honeycomb grid. The entire finite element analysis results were generated by ANSYS® 2022 workbench environment. The hatch cover provides an air tight barrier protection for the cargo. For the present simulation the original hatch cover dimensions are used (21000 × 14000 × 300 mm). The principle objective of the present paper is aimed at proposing a light-weight material, so called glass fibre reinforced plastic material over the existing steel to reduce the weight for the cargo ship to improve the efficiency by reducing fuel consumption so that dead weight is downgraded. Glass fibre reinforced hatch cover also reduces man power for the process of handling the hatch cover. Based upon the finite element analysis outcomes of different grid geometries are Square, Inclined, Diamond, Honeycomb optimal core grid of hatch cover was chosen. A scaled down model of hatch cover using glass fibre reinforced plastic with an optimal grid structure has been also developed in this paper.

The leaf spring is one of the main components in an automobile which carries the weight of the vehicle and passenger as well as absorbs the vibration and shock produced due to road irregularities. The weight, natural frequency, stress developed, energy absorption, fatigue life, etc. are the key factors that need to be considered to design a leaf spring. Towards that, a novel design integrating a Negative Stiffness Honeycomb Structure (NSHS) in the leaf spring is proposed. The proposed design and the traditional leaf spring are analyzed using the commercially available Finite Element Method (FEM) software Abaqus. Both the traditional and NSHS models were created using Solidworks and modal, harmonic, structural, and transient analyses were performed. It is found that the natural frequency of the NSHS leaf spring is well above the frequency produced due to road irregularities although it is lower than the traditional spring. The total weight of the NSHS spring structure is reduced significantly by 30.73% compared to the traditional spring. Structural analysis shows a lower stress development and higher energy absorption capacity for the NSHS leaf spring. Transient analysis reveals lower mean stress in the proposed NSHS spring. The fatigue life is also found to be 82.78 % higher in the proposed design. The NSHS-incorporated novel leaf spring design may be an excellent alternative to the traditional leaf spring.

Laminated glass is a composite structure consisting of a polymeric interlayer (e.g., polyvinyl butyral PVB) sandwiched between two glass plies. Due to the increasing use of laminated glass (LG) in advanced industries such as automotive sectors, it is of much importance to investigate the fracture behavior of such structures. One of the most critical steps in outlining the fracture behavior of laminated glass is the accurate determination of the fracture energy of the interlayer, usually, polyvinyl butyral (PVB), which is obtained from experimental methods. So far, various laboratory samples have been presented to measure the fracture energy of laminated glass, each of which has its advantages and limitations. In this paper, a new loading setup is proposed for the determination of mixed-mode I/II fracture energy in a rectangular-shape laboratory sample of laminated glass. The loading setup consists of a rectangular beam under a four-point bending which has been analyzed by the commercial ABAQUS software package. By utilizing this specimen, the fracture energy of the combined modes from pure mode I to pure mode II in the PVB interlayer can be measured. The proposed geometry here is simpler than other available geometries in the literature and also it does not require a complex loading mechanism. The effects of crack length ratio and also the support distance on fracture parameters such as and are well investigated.

This paper describes an experimental program developed to investigate non-bearing spliced composite short column connections made of Glass Fiber Reinforced Polymer (GFRP) that are subjected to axial loading. This study provides aspects such as the load-bearing capacity of the connection, failure modes, load distribution in the connection, displacement in the joint, stiffness, and compressive strength. The design of the joint in this study that connects two 350mm GFRP H-sections to form a short column connection is based on euro codes BS EN 1990 and BS EN 1991, which are used to design steel splicing connections for beams and columns. Four design specifications models are made depending on the positioning of the cover plates in the inner flange, outer flange, and web region of the H-sections to examine the requirement of a specific cover plate, and the H-sections are bolted to each other using M8 8.8 grade steel bolts. The samples tested in this study indicated a dominant failure in the flange region, with model-4 providing 92.83% compressive strength when compared to an uncut GFRP short column.

The purpose of this overview is to discover materials commonly used in the automotive industry and provide an overview of optimized composites to reduce weight, cost, fuel consumption and CO2 emissions. The cost of carbon fiber, Al and Mg lightweight composites is much higher than conventional materials. It is therefore important for research and development in the area of reducing costs, increasing recyclability, enabling integration and maximizing the fuel economy benefits of automobiles. In order to meet these characteristics, natural fibers have better properties and, in addition to being environmentally friendly, will become the material of choice for the future automotive industry. Composites can reduce weight by 10-60%. Researchers are already working with bio composites, investigating not only the economic aspects, but also the properties and associated manufacturing processes for environmentally friendly transportation and CO2 reduction.

This paper aims to investigate the impact of vehicle velocity on the rollover stability of a fully loaded tractor semi-trailer during lane changes and turning. Specifically, the study focuses on velocities ranging from 30 km/h to 60 km/h. The investigation found that vehicle velocity is a critical parameter that can affect the potential for rollover during lane changes or turning. The results showed that to ensure the vehicle moves steadily and does not roll over during these maneuvers, the steering angle must be controlled and kept within certain limits. The study provided specific recommendations for maximum steering angles at different velocities. For instance, to ensure stability when the vehicle is moving at 60 km/h, the maximum steering angle should be less than 4 degrees. Similarly, at 50 km/h, the maximum steering angle is recommended to be less than 6 degrees, and at 44 km/h, it should be less than 8 degrees. At lower speeds, the recommended maximum steering angle increases, with the maximum recommended angle at 36 km/h being 12 degrees. These findings highlight the importance of carefully controlling vehicle velocity and steering angle to minimize the risk of rollover accidents. By providing specific recommendations for different velocities, this study can inform the design and safety testing of vehicles to improve their stability and safety during lane changes and turning.

The effect of the chemical composition of geopolymer pastes on compressive strength was investigated in high-calcium fly ash and copper slag blends. In synthesizing the pastes, soda ash at activator to binder ratio of 0.4 was used. The characterization of material samples and the hardened fly ash-copper slag pastes was conducted through X-ray fluorescence (XRF), and X-ray diffraction (XRD) for the major oxide and phase composition. The hardened paste cubes which were cured at 80 °C were tested for compressive strength at ages 3, 7, and 28 days to obtain the mechanical performance property of each respective mix. The findings establish the impact of variation in the individual material and paste composition on the compressive strength of fly ash-copper slag geopolymer. The result shows that increase in the SiO₂/Al₂O₃ and Na₂O/Al₂O₃ ratios of paste products of samples corresponded to an increase in compressive strength. Whilst Fe₂O₃ wt.% increase in products from slag addition and positively influenced the compressive strength as fillers. However, CaO had no positive influence on the matrix of the activated product. The optimal blend mix design was 40 wt.% of copper slag which achieved a 28-day compressive strength of 24.66 MPa.