Papers by Keyword: Impact Energy

Abstract: The demand for environmentally sustainable methods to enhance the performance of low-carbon steel (LCS) has led to increased interest in organic waste-derived carburizing agents. This study explores the potential of using a blend of Shea Nut Shell (SNS) and Eggshell (ES) ash, mixed in a 1:3 ratio, as an eco-friendly carburizing medium for improving the mechanical and corrosion-resistant properties of LCS. Carburization was carried out at 900°C for 30 minutes, and the effects were assessed through comprehensive characterization. Mechanical properties such as hardness, tensile strength, and impact energy were evaluated alongside microstructural analysis using X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS), and wear rate testing. Corrosion resistance was investigated in H₂SO₄ and NaCl environments over a 21-day period. Results show that carburized LCS achieved significantly higher hardness (514.55 HB) compared to the uncarburized counterpart (399.05 HB), with improved toughness as indicated by increased impact energy absorption. However, un-carburized LCS maintained higher tensile strength. Microstructural examination revealed enhanced carbon diffusion and pearlite formation, contributing to reduced wear in carburized samples. EDS confirmed increased surface carbon content, while corrosion behavior varied: carburized LCS performed better in saline (NaCl) conditions, whereas uncarburized LCS offered better resistance in acidic (H₂SO₄) environments. In conclusion, the SNS-ES ash mixture presents a promising route for sustainable carburization of LCS, particularly for components exposed to saline environments such as agricultural tools and automotive parts. Future work will focus on optimizing treatment durations, expanding corrosion testing in simulated service environments, and scaling the process for industrial applications.

Abstract: The structural response of materials under dynamic impact loads is crucial in protective design, particularly in applications where energy absorption is a primary concern. This study presents a comprehensive experimental investigation into the energy storage potential of additively manufactured polymeric axial members subjected to high-speed and low-speed impact tests. These axial members were fabricated using additive manufacturing techniques, emphasizing optimizing their structural performance under deformation. The study focuses on assessing the performance of various internal infill geometries to enhance energy dissipation during impact loading. A series of tests was conducted to evaluate the members' capacity to absorb impact energy and to compare their performance under varied strain rates. The findings indicate that specific infill patterns significantly improve energy absorption capabilities, making them suitable for applications involving blast and impact-resistant designs. Furthermore, the results demonstrate that careful optimization of the internal structure of 3D-printed elements can effectively reduce the adverse effects of dynamic loads, making them a promising option for protective structures. The findings contribute to a broader understanding of material behavior at high strain rates, provide valuable guidance for designing lightweight, impact-resistant components, and provide new perspectives on utilizing innovative materials and manufacturing techniques to enhance structural resilience in demanding environments.

Abstract: This research investigated the mechanical properties, impact resistance, and behavior under elevated temperatures of Fiber Rubberized High-Strength Concrete (FRHSC), which incorporates Waste Steel Fiber (WSF) and Crumbed Rubber (CR) obtained from waste tires. The study involved five different concrete mixtures to explore the impact of WSF and CR. WSF was consistently mixed in a ratio of 0.3% by volume of the concrete. CR was used to partially replace the fine aggregate in proportions of 10%, 20%, 30%, and 40% by volume. The study examined various characteristics of both the fresh and hardened FRHSC, including slump, unit weight, compressive, tensile, and flexural strengths, as well as its impact resistance. The effects of elevated temperatures at ambient, 200 °C, 400 °C, and 600 °C for a period of 2 hours were also analyzed, focusing on the failure shape, and residual compressive strength. Findings indicated that as the quantity of rubber in the concrete samples increased, there was a noted gradual decline in their mechanical properties. Concurrently, this increase in rubber content contributed to an enhancement in the ductility of the samples. The energy absorption by the rubberized specimens was found to be consistent, regardless of the variation in rubber content due to the presence of WSF. The residual compressive strengths of FRHSC subjected to elevated temperatures improved with the addition of CR. The presence of CR led to an increase in the concrete's porosity, and exposure to high temperatures resulted in more cracks due to CR evaporation and the replacement of air voids, causing a notable reduction in compressive strengths. Keywords Fiber reinforced Concrete; Crumb rubber; waste steel fiber; waste tires, Rubberized concrete; Impact energy; Mechanical properties; Elevated temperature.

Abstract: The present research focuses on the hot forging of 38MnSiVS5 micro-alloyed steel, examining the impact of key process variables, such as working temperature, deformation percentage and rate of cooling on mechanical properties, notably the ultimate tensile strength and impact energy. To optimize the process, Taguchi's parametric design, utilizing an orthogonal array in combination with grey relational analysis and fuzzy logic analysis, has been implemented. By applying grey-fuzzy logic analysis, the optimization of complex multiple responses is streamlined into a single grey-fuzzy reasoning grade. The study employs the Grey fuzzy logic method to concurrently optimize both responses. The grey-fuzzy reasoning grade serves as a performance index, aiding in the determination of the optimal process parameter settings for both the ultimate tensile strength and impact energy responses simultaneously.

Abstract: Natural fiber reinforced polymer composites have become more attractive due to their high specific strength, light weight and environmental concern. However, some limitations such as low modulus and poor moisture resistance were reported. This paper presents the role of halloysite nanotubes (HNTs) on physico-mechanical properties of bidirectional silk and basalt fiber reinforced epoxy (SF-BF/Ep) hybrid composites. Vacuum bagging and ultra-sonication method were used for the fabrication of hybrid composite slabs. The effect of HNT loadings (1.5, 3 and 4.5 wt. %) on physico-mechanical characteristics like density, hardness, flexural and impact properties of SF-BF/Ep composites were determined according to ASTM standards. Experimental results revealed that the incorporation of HNTs improves the mechanical properties. The impact strength of SF-BF/Ep is predominant at 3 wt. % HNT loading where the impact strength surges to 568.67 J/m, which may render HNT filled SF-BF/Ep desirable for various toughness-critical structural applications. The test results demonstrated that SF-BF/Ep-3HNT coded composites exhibited improved mechanical properties among the all composites.

Abstract: The study of the impact energy and the composite behaviour plays a vital role in the efficient design of composite structures. Among the various categories of impact tests, it is essential to study low-velocity impact tests as the damage generated due to these loads is often not visible to the naked eye. The internal damages can reduce the strength of the composites and hence the impact behaviour must be addressed specifically for improving their applications in the transport industry. The main aim of this paper is to provide a comprehensive review of the work focusing on the assessment of biocomposites performance under low impact velocity, the different deformations, and damage mechanisms, as well the methods to improve the impact resistance.

Abstract: In heavy industries like mining or steel production vast amounts of loose materials need to be transported, relocated or otherwise processed. During these routines severe stresses are applied on heavy machinery components such as excavator grabs and clamshells, which ultimately lead to excessive wear. The dominant wear mechanisms under such conditions are impact and abrasion. The focus of this paper is to investigate the fracture behaviour of various abrasives as experienced under real application in the steel industry. Breaking events of abrasive particles affect the impact energies on tool equipment. The Cyclic Impact/Abrasion Test rig (CIAT) was applied to investigate the stability and fracture behaviour of the abrasives. Rotating counter bodies made of martensitic quenched and tempered steel were used to generate impact events on loose abrasive particles. After certain time intervals the abrasives were screened and particle size fractions documented. Impact energy is strongly dependent on size and density, as well as fragility and cracking of particles. As fracturing events diminish particle dimensions and shift size distributions to lower size fractions, each abrasive showed a distinctive impact energy distribution over the course of the test duration. Impact energy distributions of abrasives were correlated to wear rates of the steel samples for each abrasive used. The results indicate a distinct behaviour of each abrasive, yielding certain impact energy distributions. Depending on processing specific abrasive goods in actual applications, impact energies and associated wear loss can differ significantly.

Abstract: In this paper, the effect of heat treatment on the microstructure and mechanical properties of hot forging Cu-Ni alloy was studied. Specimens of hot forged Cu-Ni alloy were subjected to first solution treated at 900^oC for 2hrs and then aged at different temperatures for 2hrs. The mechanical properties including tensile performance and impact energy, and the microstructure were measured for specimens before and after heat treatment. The results show that both solution and aging treatment have an influence on the grain growth. After heat treatment, the tensile strength decreases very slightly but the yield strength decreases seriously from 235.96MPa to 136.12MPa, while the elongation increases sharply from 36% to 48%. It was also observed that hardness values of the heat-treated alloys are all lower than that of the hot forged alloy. The measurement of Charpy impact energy with V-type notch was performed at 298K and 77K for different specimens. At both temperatures, the impact energies of the specimens are higher than 200J. The microstructure results show that at both temperatures, the alloys are fractured in a ductile mode.

Abstract: This study is a kinematic model of a mechanical mill that works with a single ball in motion, and which is operated by a crank and connecting rod system for producing nanocrystalline powders by the process of ball milling. The geometric and dynamic parameters play an important role on the variation of forces created upon impact of the ball with the inside wall of the vial, which caused energy transfer required for the mechanical alloying process. The determination of these forces enables us to know their specific magnitudes on the intensity and milling efficiency, with the advantage of low operating power consumption of the mill and absence of the contamination problem. In addition, we have defined a model for calculating the temperature of the powder trapped between the ball and the wall of the vial of the mechanical mill whose start-up is provided by an electric motor.

Abstract: The principal difference between the SP testing technique and standardized Impact testing lies in the fact that the SP tests carried out in accordance with CWA 15627 use disc-shaped test specimens without a notch. Especially in tough materials, the temperature dependence of fracture energy in the transition area is ​​very steep and lies close to the temperature of liquid nitrogen. In this case, t he determination of T _SP can lead to significant errors in its determination . Efforts to move the transition area of penetration testing closer to the transition area of standardized impact tests led to the proposal of the notched disc specimen 8 mm in diameter and 0.5 mm in thickness with a “U" shaped notch 0.2mm deep in the axis plane of the disc.The paper summarizes the results obtained to date when determining the transition temperature of Small Punch tests, T_SP, determined according to CWA 15627 for material of pipes made of P92 and P22 steels in the as delivered state and a heat treated 14MoV6-3 steel. Although the results obtained confirmed the results of other workers in that the presence of a notch in a SP disc is insufficient to increase the transition temperature significantly and certainly not to the values obtained by Charpy testing, comparison of the different behaviours of the alloys tested reveals some evidence that the notch reduces the energy for initiation. This implies that the test on a notched disc is more a test of crack growth and would be a useful instrument if included in the forthcoming EU standard for SP testing.