Papers by Keyword: Tensile Test

Abstract: Modern manufacturing increasingly demands energy-and resource-efficient solutions. Conventional metal forming often requires high temperatures to reduce flow stress, resulting in high energy consumption, especially for low-formability alloys. Electrically-Assisted Manufacturing (EAM) has emerged as a promising alternative, leveraging the electroplastic effect, i.e. electricity’s direct influence on plastic deformation. Documented benefits include reduced forming forces, improved ductility, and altered fracture modes. Indeed, integrating electroplasticity into manufacturing aligns with Industry 4.0 and decarbonization goals, enabling lower energy consumption, extended tool life, and greater compatibility with renewable energy sources. This study compares conventional tensile testing and electro-assisted tensile testing (EAM) of Ti6Al4V, evaluating both mechanical results and the energy consumption of the testing machine under different conditions. The comparison results highlight the potential of pulsed current to improve material formability while reducing energy consumption, offering a more sustainable approach to manufacturing.

Abstract: This study investigates the effects of various cutting technologies on a 0.25 mm thick ferritic steel, a material widely used in packaging and other lightweight applications. The study provides a comprehensive comparison of four distinct cutting technologies: Laser Cutting, Milling, Electrical Discharge Machining (EDM), and Water Jet Cutting. The research focuses on the impact of these cutting processes on the material’s properties and its performance under uniaxial tension. X-ray diffraction is used to precisely measure the magnitude and distribution of residual stresses along the cut edge in order to correlate them with changes in the material's flow curve, which is critical for accurate mechanical characterization. Furthermore, a laser-scanning microscope was used for detailed morphological analysis of the cut edge and for roughness measurement. To quantify mechanical property changes, microindentation hardness testing was used to assess the degree of work hardening induced by each cutting method. Finally, Digital Imaging Correlation (DIC) was employed to track strain distribution and observe strain field variations.

Abstract: Forming limit curve (FLC) is the most common used manifestation of the failure criterion today in the sheet metal forming industry. All commercial simulation software uses this concept to evaluate the failure strains and to detect the most dangerous section(s) of the workpiece. The laboratory determination of the FLC is standardized. However, because experimental measurement is cumbersome, theoretical calculations of FLCs using mechanical properties from well-defined test conditions are still interesting. Such calculation concepts are already developed by different authors. This paper presents calculated FLCs using the models of Abspoel et al., Stören and Rice and Swift. All the equations include tensile tests data that have been measured physically at room temperature, with quasi-static strain rates. Calculated results of DC04 cold rolled steel sheet with relatively high plastic anisotropy coefficient was compared to a nearly isotropic DP800 high strength steel. Based on the results it is observed that r-value influences the shape of the left-hand side of the FLC as well as the plane strain point significantly, for the DC04 sheet. These effects are less pronounced for the DP800 material, which has lower r-value. At the same time, n-value and total elongation raise or lower the curves, generally. These observations are briefly explained by function analyses using fictitious r-values in the calculations.

Abstract: For high-accuracy finite element (FE) simulation of automobile crashing behavior, a work hardening curve that involves pre-strain from press forming is required. Here, the plastic strains exceeding the uniform deformation region are generally introduced through processes such as bending, but such large pre-strain effect have not been reported. Therefore, in this study, for DP590 steel, the work hardening curve for second-stage tension under pre-strain exceeding the uniform deformation region was identified. This identification was enabled by the diameter measurement tensile test developed by the authors. As a result, in the second-stage tension in the same direction as the first-stage tension, the initial yield stress showed a tendency to overshoot relative to the original work hardening curve, revealing that strain aging occurred. The overshoot portion formed a stress plateau that continued up to an equivalent plastic strain of 0.18. Such a tendency has not been observed in DP590 steel, making this a phenomenon revealed for the first time. When the tensile direction in the second stage was orthogonal to the first stage, the cross-hardening effect (reduction in initial yielding due to the Bauschinger effect and overshoot from the original work hardening curve) was observed. The stress plateau region due to overshoot continued up to an equivalent plastic strain as large as 0.6. These large plateaus concluded that work hardening presents perfect plasticity at large deformed press parts.

Abstract: This research explores the effect of elevated extrusion ram speed—achieved through die cooling with liquid nitrogen—on the mechanical behavior of 6060-aluminum alloy profiles. Mechanical characterization was conducted via tensile testing and nanoindentation, with the latter also employed to assess the alloy’s creep response. Results reveal that while the increased ram speed exerts minimal impact on Ultimate Tensile Strength (UTS) and Yield Tensile Strength (YTS), it notably enhances elongation. Furthermore, the study demonstrates a significant influence of ram speed on creep displacement as the dislocations generated by higher ram speeds seems to improve the creep resistance of the material. Keywords: 6060 Aluminum Alloy; Liquid Nitrogen Cooling; Nanoindentation; Tensile Testing; Creep Behavior.

Abstract: Traffic control devices are a compulsory component of any road network. Theft of metallic signs is a growing issue in many developing countries. It leads to safety risks and financial losses. . This study explores a sustainable alternative to traffic control devices by introducing fiberglass sheets and bamboo posts as the primary manufacturing materials. A schematic of the developed signpost assembly is presented. Market survey conducted in Karachi confirms that fiberglass has negligible resale value, making it less susceptible to theft. Mechanical testing, including tensile and flexural assessments, showed reliable strength. The material achieved an average tensile strength of 4.45 kN and a flexural strength of 36 MPa, suitable for outdoor use. The total estimated cost per unit is PKR 5,400, offering a low-cost alternative to conventional materials. These results support the variability of the proposed design for deployment in resource-constrained and theft-prone environments.

Abstract: Recently, there has been a growing interest in replacing synthetic fibres with natural fibres in polymer composites due to environmental concerns. This study examined the fibres from the Newbouldia laevis plant for their potential use in lightweight polymer composites, particularly in applications sensitive to strength and temperature. The fibres were extracted from the plant's stem, and various properties such as density, moisture content, moisture regain, and diameter were measured. Chemical analysis revealed the percentages of cellulose, hemicellulose, lignin, extractives, and ash present in the fibres. Furthermore, Fourier transform infrared analysis confirmed the presence of these essential components. Scanning electron microscopy images showed the rough surfaces of the fibres, which enhance the adhesion between the fibre and matrix during the production of polymer composites. Energy dispersive X-ray analysis identified carbon and oxygen as the main elements in the fibres. Thermal analysis provided insights into the thermal stability and maximum degradation temperatures of the fibres. Lastly, a single fibre tensile test was performed to evaluate the tensile strength, elastic modulus, and elongation at break of the fibres using Weibull distribution statistical analysis. The results of this study indicate that Newbouldia laevis fibres could be a promising reinforcement for lightweight polymer composites in strength and temperature-sensitive applications.

Abstract: The primary objectives include investigating the mechanical properties of used construction steel, and evaluating the feasibility of reusing the old materials in green construction projects. The methodology involves gathering samples from demolition sites which are over 40 to 50 years old(1980-1985 construction sites), conducting mechanical testing (such as tensile test and bending test), and performing microstructural analysis.By promoting the utilization of used construction steel, the project seeks to reduce waste, lower material costs, and minimize the environmental impact for sustainable activities. The results we found were that the average maximum load the material can bear was 1.35KN and was bended till 6mm. The average grain size of the material was found to be 20µm. the average elongation percentage came out to be 15.27% and the elements of the material identifies that it is of grade A-36 Steel.Ultimately, this project aspires to facilitate a shift towards more eco-friendly construction practices and supporting the construction industry's transition to sustainable development.

Abstract: This study discusses the performance and durability of manganese steel wire ropes under different loading conditions and environmental exposures. Steel wire ropes are critical elements in several industries that require high tensile strength and elasticity. It is driven by the fact that these ropes fail prematurely within two years of service despite them being designed for five years during the process of fabrication. The nature and cause of these premature failures can be attributed to residual stresses, which increase the wear, fatigue, and corrosion. These tests included tensile testing at various strain rates in both the aged and unaged states, and fatigue testing performed under a 0.7 strain rate in a purely non-pre-strained state, and pre-strained under the three conditions of dry pre- strain, corrosion pre-strain, and aging pre-strain. An SEM analysis was performed to determine the failure mechanism. An increase in the strain rate reduced the lifespan but increased the yield and ultimate tensile strength; the 0.7 strain rate represented the highest energy density compared to the strain rates of 0, 0.43, 1.0 and 1.35 strain rate. This study highlights the critical role of residual stress in steel wire ropes in terms of their performance and lifetime. The residual stress increased with the strain rate. Corrosive conditions showed a drastically reduced fatigue life, and the non-pre-strain condition had the longest cycles. Understanding the mechanical effects of steel wire ropes and optimizing the testing conditions will increase the durability and reliability of steel wire ropes with reduced maintenance costs and increased safety in industrial applications.

Abstract: The selection of biomaterials and the design of the scaffold is crucial, as it directly influences the mechanical properties, which in turn affect cell behavior and tissue integration. This study investigates how scaffold geometry impacts mechanical characteristics, with the aim of replicating the properties of natural tissues. Auxetic geometries, characterized by negative Poisson’s ratios, were investigated. These structures exhibit unique mechanical behavior, expanding laterally when stretched, in contrast to conventional materials that contract. The Fused Deposition Modeling (FDM) technique was used to 3D print scaffolds with a single filament of polycaprolactone (PCL). Two geometries, wavy and sinusoidal, were analyzed by varying the amplitude of the curve within each structural cell. Tensile tests were performed to measure mechanical properties, including Young’s Modulus (E), Poisson’s ratio (ν), and porosity-properties critical for understanding the interaction of scaffolds with cells and tissues. The wavy geometry exhibited a higher E than the sinusoidal geometry at the same amplitude. At a minimum amplitude of 0.3 mm, the wavy structure had E = 6.8 MPa, while the sinusoidal structure had E = 3.8 MPa. At the maximum amplitude of 1.2 mm, the wavy structure had E = 0.6 MPa, and the sinusoidal structure had E = 0.2 MPa. All Poisson’s ratios were negative, with the lowest value (-1.56) observed in the sinusoidal structure at the largest amplitude. The detected negative Poisson’s ratio suggests auxetic behavior, which could enhance scaffold flexibility, improve its ability to deform, promote cell attachment, and facilitate tissue integration. Although the two auxetic structures shared the same undulation angle, the analysis revealed differences in their mechanical properties. Specifically, the wavy structure exhibited a lower Young’s Modulus. To improve cell interaction and attachment by reducing pore size, a correction factor was calculated based on stiffness values and pore area measurements. By adjusting the scaffold geometry, its mechanical properties can be fine-tuned to more closely align with the characteristics of native tissues, potentially enhancing cell attachment and proliferation. This study highlights the potential of modifying scaffold geometry, particularly through the use of auxetic structures, to significantly influence mechanical properties. This approach shows promise in optimizing scaffolds for tissue engineering applications.