Variations In Tensile Properties Research Articles

Transverse tensile behavior of carbon fiber/epoxy composite at different temperatures and strain rates

AbstractThis research explores the transverse tensile properties of a unidirectional carbon fiber/epoxy composite under quasi‐static and dynamic conditions, across various temperatures (−30, 25, 85°C). To conduct the investigation, a universal testing machine and a split Hopkinson tensile bar are utilized. The findings reveal that the transverse tensile properties are influenced by temperature and strain rate. At −30, and 25°C, the quasi‐static stress and strain curves exhibit linearity, while at 85, nonlinearity is observed. On the other hand, the dynamic stress and strain curves demonstrate approximate linearity across all temperatures. The quasi‐static tensile strength decreases with rising temperature, but the dynamic tensile strength remains relatively unaffected by temperature variations. Furthermore, both the quasi‐static and dynamic tensile elastic moduli decrease as temperature increases. The transverse tensile strength and elastic modulus exhibit an approximately linear relationship with the logarithm of the strain rate. The study also delves into the analysis of fracture morphologies and mechanisms through macroscopic and microscopic observations. By introducing the dynamic enhancement factor of strain rate, the formulas of the transverse tensile strength and elastic modulus at different temperatures are proposed. These formulas provide a comprehensive representation of the experimental results.Highlights Tensile properties at different temperatures and strain rates are tested. Stress and strain curves at various temperatures and strain rates are studied. Variation of tensile properties with temperature and strain rate is analyzed. Change of fracture mechanism with temperature and strain rate is discussed. Formulas for transverse tensile strength and elastic modulus are given.

Effects of Resting Conditions on Tensile Properties of Acid Aggregate Hydraulic Asphalt Concrete.

This study addresses the issue of construction stagnation affecting the adhesion and tensile properties of hydraulic asphalt concrete with acid aggregate. It investigates the impact of rest periods on the tensile characteristics of such materials under standard construction conditions. The influence of varying rest durations and asphalt temperatures on the tensile behavior of the concrete is assessed through indoor experiments. The bonding between asphalt and aggregate is examined, along with the tensile property variations of the concrete. The study found that the standstill time significantly affects the adhesion of asphalt, with the adhesion decreasing progressively with increased temperature and rest time, irrespective of the addition of anti-stripping agents. However, the inclusion of these agents can mitigate the reduction in adhesion. Furthermore, the study identified that rest duration has a more substantial impact on adhesion than temperature. The splitting tests demonstrate that the tensile properties of asphalt concrete are considerably affected by the resting time. Over a period of 0, 10, 20, and 30 days of rest, an increase in splitting strength and a decrease in splitting displacement were observed. The findings offer valuable insights for predicting the tensile performance of asphalt concrete in practical engineering applications after a period of rest.

Effects of gamma radiation on cyclic olefin copolymers with varied norbornene content: Impacts on structure and properties at sterilization doses

Effects of gamma radiation on cyclic olefin copolymers with varied norbornene content: Impacts on structure and properties at sterilization doses

The Effects of Layer Thickness on the Mechanical Properties of Additive Friction Stir Deposition-Fabricated Aluminum Alloy 6061 Parts

Solid-state additive friction stir deposition (AFSD) is a thermomechanical-based additive manufacturing technique. For this study, AFSD was utilized to produce aluminum alloy 6061 (AA6061) blocks with varying layer thicknesses (1 mm, 2 mm, and 3 mm). The mechanical properties were assessed through uniaxial tensile tests and Vickers microhardness measurement, and statistical analysis was employed to investigate differences among data groups. The results revealed that the deposition layer thickness influences tensile properties in the building (Z) direction, while the properties in the X and Y directions showed minor differences across the three AFSD blocks. Furthermore, variations in tensile properties were observed depending on the sample orientation in the AFSD blocks and its depth-wise position in the part in the building direction. The microhardness values decreased non-linearly along the building direction, spread across the width of the part’s cross-section, and highlighted that the deposition layer thickness significantly affects this property. The 1 mm block exhibited lower average microhardness values than the 2 mm and 3 mm blocks. The temperature histories and dynamic heat treatment are influenced by the deposition layer thickness and depend on the location of the point being studied in the part, resulting in variations in the microstructure and mechanical properties along the building direction and across the part’s width.

Mechanical Characterization of the Human Abdominal Wall Using Uniaxial Tensile Testing.

It is generally accepted that the human abdominal wall comprises skin, subcutaneous tissues, muscles and their aponeuroses, and the parietal peritoneum. Understanding these layers and their mechanical properties provides valuable information to those designing procedural skills trainers, supporting surgical procedures (hernia repair), and engineering-based work (in silico simulation). However, there is little literature available on the mechanical properties of the abdominal wall in layers or as a composite in the context of designing a procedural skills trainer. This work characterizes the tensile properties of the human abdominal wall by layer and as a partial composite. Tissues were collected from fresh-never-frozen and fresh-frozen cadavers and tested in uniaxial tension at a rate of 5 mm/min until failure. Stress-strain curves were created for each sample, and the values for elastic moduli, ultimate tensile strength, and strain at failure were obtained. The experimental outcomes from this study demonstrated variations in tensile properties within and between tissues. The data also suggest that the tensile properties of composite abdominal walls are not additive. Ultimately, this body of work contributes to a deeper comprehension of these mechanical properties and will serve to enhance patient care, refine surgical interventions, and assist with more sophisticated engineering solutions.

Effect of Rice Husk and Wood Flour on the Structural, Mechanical, and Fire-Retardant Characteristics of Recycled High-Density Polyethylene.

Given the rising consumption of plastic products, it is becoming imperative to prioritize the recycling of plastic items as a solution to reducing plastic waste and environmental pollution. In this context, this research focuses on assessing the impact of incorporating rice husk and wood flour into recycled high-density polyethylene (rec-HDPE) to analyze its mechanical properties, flammability, and thermal stability. The combined rec-HDPE content of wood flour and rice husk varied between 0% and 20%. The rec-HDPE content of maleic anhydride grafted polyethylene (MAPE) was fixed at 3%. Mechanical characteristics such as flexural, tensile, and impact strengths were assessed. Cone calorimetry (CC) tests, limited oxygen index (LOI) tests, and horizontal and vertical burning tests were performed to determine the flammability or fire retardancy of these composites. On the other hand, to characterize the thermal characteristics of these composites, thermogravimetric analysis (TGA) was used. To further characterize the fluctuation in these characteristics, scanning electron microscopy (SEM) and infrared spectroscopy (FTIR) studies were carried out. The mechanical characteristics were found to be increased in response to adding rice husk or wood flour. An 8% increase in tensile strength and a 20% increase in elastic modulus enhancement were recorded for a 20% rice husk-added composite. SEM revealed the reason for the variation in tensile properties, based on the extent of agglomeration and the extent of uniform distribution of fillers in rec-HDPE. Following these lines, the 20% rice husk-added composite also showed a maximum increase of around 6% in its flexural strength and a maximum increase of 50% in its flexural modulus. A decrease in impact strength was recorded for rice husk and wood flour-reinforced composites, compared with unreinforced rec-HDPE. Hybrid composites displayed a lack of mechanical strength due to changes in their nature. FTIR tests were performed for a much more elaborate analysis to confirm these results. Twenty percent of rice husk-added rec-HDPE displayed the best thermal properties that were tested, based on TGA and derivative thermogravimetric (DTG) analysis. This 20% composite also displayed the best fire-retardancy characteristics according to UL 94 tests, cone calorimetry tests, and limited oxygen index tests, due to the barrier created by the silica protective layer. These tests demonstrated that the incorporation of both fillers-rice husk and wood flour-effectively enhanced the thermal, mechanical, and fire-retardant attributes of recycled HDPE.

Effects of infill temperature on the tensile properties and warping of 3D-printed polylactic acid

Although extensive research has been carried out on the effects of temperature on the properties of parts by fused filament fabrication, no study considered the opportunity to use different temperatures and cooling strategies for the contour and the infill region. The purpose of this investigation is to explore such an opportunity through an experimental campaign on polylactic acid. Specifically, the variations in tensile properties and warping occurring with different infill temperatures and cooling methods are documented. The results demonstrate that diversifying process parameters used for the contour and infill of the part allow for significant improvements in mechanical properties without affecting the distortion of the manufactured samples. This result can be achieved by either increasing the nozzle temperature or switching off the cooling fan during infilling.

Assessment of tensile properties across pressure vessel nozzle to primary piping safe-end employing instrumented indentation testing

Assessment of tensile properties across pressure vessel nozzle to primary piping safe-end employing instrumented indentation testing

Precipitates evolution during isothermal aging and its effect on tensile properties for an AFA alloy containing W and B elements

A 20Cr-25Ni-2.5Al alumina-forming austenitic alloy containing W and B elements was aged at 923 K for 5000 h, and the microstructure and tensile properties with different aging time were investigated. NiAl, σ and Laves were observed at grain boundaries (GBs) successively. The matrix was covered by NiAl and Laves with the extension of aging. The evolution of precipitates during aging contributed to the variation of tensile properties. Precipitation of nanosized NbC carbides within grains and σ phase at GBs led to a rapid increase in strength and a decrease in elongation for 500 h aging sample. In the later stage of aging, the coarsening of NiAl and Laves phases, as well as the reduction in dislocation density caused a decline in strength. The coarsening of precipitates upon aging time follows the Ostwald ripening theory. Due to its lower diffusion rate in austenite compared to Mo, W may accelerate the growth of Laves at GBs. Boron was mainly enriched in Laves instead of NiAl, NbC and σ phases after high temperature aging. The addition of W and B improved the precipitation strengthening of Laves, increasing the high temperature tensile strength after long term thermal aging. The difference in tensile properties between room temperature and 923 K is due to the ductile–brittle transition of NiAl. No σ phase was observed within grains even after 5000 h aging and elemental chromium particles occurred around Laves due to boron hindering the growth of σ.

Durability of High-Density Polyethylene (HDPE)- and Polypropylene (PP)-Based Wood-Plastic Composites—Part 1: Mechanical Properties of the Composite Materials

Wood-plastic composites (WPCs) have shown exceptional promise as a building material, especially for outdoor uses. Using renewable wood fiber as the reinforcing filler in WPCs increases the material’s environmental sustainability. While virgin commodity thermoplastics are primarily used in these composites, using post-consumer plastic further contributes to their sustainability. While they are beginning to be used in the Gulf countries, information on their performance, especially durability under harsh desert climates, is sparse. The present investigation on WPCs is based on the two most popularly used thermoplastics in WPCs, virgin high-density polyethylene (HDPE) and polypropylene (PP), with the wood content varying between 0 and 36 wt. %. These were prepared with melt processing from a masterbatch and characterized primarily using thermal methods and tensile properties of their injection molded test pieces. Variations in tensile properties, especially the tensile modulus (MPa), the tensile strength (MPa), and the ultimate extensibility (%) of the composite samples were investigated to determine an optimal wood-fiber loading. For either polymer type, exceeding 27 weight percent of wood fiber resulted in unacceptably low ultimate extensibility of the material.

Examination of steel compatibility with additive manufacturing and repair via laser directed energy deposition

High strength steels are a vital material for aerospace applications but are also prone to damage from fatigue, corrosion, and wear. Additive manufacturing (AM) processes such as laser directed energy deposition (L-DED) offer a means for repairing both the geometry and structure of damaged steels; however, significant variation in tensile properties have been reported following repair. While previous studies have tried to improve performance through postdeposition heat treatment, such practices may not be possible for commercial parts due to risks of distortion and thermal damage to the substrate. Instead, this investigation analyses the role of the intrinsic heat treatment effect on as-deposited tensile properties through a detailed review of both AM and AM repair literature. By assessing a wide variety of high strength steels, the links between conventional heat treatment parameters and steel performance in AM are established, and the role of steel composition understood. This review is supported by additional AM and L-DED repaired samples, with consistent parameters used between steels to ensure similar thermal histories, and eliminate potential discrepancies seen between AM machines. The results demonstrate the effect of intrinsic heat treatment on martensitic and precipitation hardening steels, the role of residual heat and heat extraction through the substrate, and flag potential issues faced by steels at risk of temper embrittlement. Taken together, these findings provide a clear vision for the advancement of AM repair and the optimization of mechanical performance.

Effects of work-hardening and post thermal-treatment on tensile behaviour of solder-affected copper

In order to explore the reuse potential of waste/scraped copper, an effective characterization of its functional properties under various operating conditions is of great practical importance. The present paper is an attempt to reconnoiter the solder-affected waste copper for high-value engineering applications through the characterization of major mechanical properties. More specifically, the tensile properties of traditional lead-solder-affected copper are investigated and analyzed under the influence of work-hardening and post-thermal treatments. The influential effects of individual elements of the solder on the tensile properties of copper are discussed in a comparative fashion, in which two additional alloy samples, namely, high-copper/tin alloy and high-copper/lead alloy are taken into consideration together with those of copper–tin–lead–alloy as well as pure copper samples. The results of the investigation show that the inclusion of trace-amount of tin and lead in copper affects the corresponding tensile behaviour quite significantly. The strength rising trends due to cold working are observed to be more prominent for the inclusion of lead compared to that of tin. The post-thermal treatments of the work-hardened alloy samples have lowered ultimate strength, yield strength and elastic modulus, but increased the fracture elongation at elevated temperatures. Strain rate variations are also found to be highly influential on all the tensile properties of the solder-affected alloys. Micrographs of the alloy samples have verified the changes in grain shape and grain size responsible for the variation of tensile properties.

Microstructure and enhanced tensile properties of AlCo CrFeNi high entropy alloys with high Co content fabricated by laser melting deposition

Microstructure and enhanced tensile properties of AlCo CrFeNi high entropy alloys with high Co content fabricated by laser melting deposition

Influence of ageing on high temperature tensile deformation of a Ni-based superalloy, HAYNES 282

Influence of ageing on high temperature tensile deformation of a Ni-based superalloy, HAYNES 282

Relationship between microstructure and strain-hardening behaviour of 3D printed engineered cementitious composites

Relationship between microstructure and strain-hardening behaviour of 3D printed engineered cementitious composites

Precipitate coarsening and mechanical properties in 6082 aluminium alloy during long-term thermal exposure

Precipitate coarsening and mechanical properties in 6082 aluminium alloy during long-term thermal exposure

Assessment of intra-build variations in tensile strength in electron beam powder-bed fusion Ti–6AL–4V part 1: Effects of build height

Assessment of intra-build variations in tensile strength in electron beam powder-bed fusion Ti–6AL–4V part 1: Effects of build height

Assessment of intra-build variations in tensile strength in electron beam powder-bed fusion Ti–6Al–4V part 2: Effects of powder mixing

Assessment of intra-build variations in tensile strength in electron beam powder-bed fusion Ti–6Al–4V part 2: Effects of powder mixing

Microstructure and mechanical behaviors of Al/Cu laminated composites fabricated by accumulative roll bonding and intermediate annealing

Microstructure and mechanical behaviors of Al/Cu laminated composites fabricated by accumulative roll bonding and intermediate annealing

Interfacial microstructure and property of 6061 aluminium alloy/stainless steel hybrid inertia friction welded joint with different steel surface roughness

Interfacial microstructure and property of 6061 aluminium alloy/stainless steel hybrid inertia friction welded joint with different steel surface roughness