Tensile Elastic Modulus Research Articles

A Study on the Microstructure, Tensile and Fatigue Properties of Martensitic Stainless Steel Plate

The microstructure, tensile and fatigue properties of a martensitic stainless steel (MSS) plate with a thickness of 0.152 mm are investigated in this study. The microstructural properties were initially studied using electron backscatter diffraction microscopy. High dislocation densities were observed in the microstructure, along with the rolling texture revealed by the pole figure, following an initial cold rolling process of the as-received MSS plate. Tensile tests were conducted in both the rolling and transverse directions to compare the strength of the material in both directions. The results showed that the tensile strength was relatively low in the rolling direction. This can be attributed to the microstructure and crystallographic orientation of the material along that direction. Additional tensile tests were performed at various temperatures within the operating temperature range in the rolling direction. The results indicate that the highest tensile strength and elastic modulus are observed at room temperature. A high-cycle fatigue test was performed to determine the fatigue limit of the MSS plate. Furthermore, the microstructure was analyzed by controlling the fatigue cycles within the same stress range. The results revealed a proportional relationship between the accumulated deformation within the grains and the fatigue cycles. This can be helpful in understanding the fatigue damage mechanisms of the MSS plate.

A screw extrusion-based system for additive manufacturing of wood: Sodium silicate thermoset composites

The aims of this work were to investigate the printability of high-fraction wood and sodium-silicate composites (WSSC) for additive manufacturing and to develop a screw extrusion-based process to demonstrate this approach for building construction applications. A custom additive manufacturing system was fabricated, and mixtures of 40%–60% wood fiber and 60%–40% sodium silicate were printed. The printability of these formulations was determined by observing their viscosity, extrudability, print-bed and layer adhesion, and curing characteristics. Fiber to resin ratios of 45:55 to 50:50 were the most suitable for printing. The printability was also affected by printing temperature and nozzle travel speed. The mechanical properties of printed and cured WSSC, were determined by three-point bending, tensile, and compression testing. Tensile strength, bending strength, and elastic modulus were found to be comparable to those of 3D printed concrete and other wood-plastic composites reported in the literature. The WSSC was successfully printed into a panel indicating promise for use in additive manufacturing.

An investigation of durability and the mechanical properties of ultra-high performance concrete (UHPC) modified with economical graphene oxide nano-sheets

The use of Nano-materials in the matrix of ultra-high-performance concrete (UHPC), due to its superior properties, mainly improve durability and the mechanical properties, and increase the concrete performance. In UHPC, carbon-based nanomaterials are one of the most widely used nanomaterials. In this research, industrial graphene oxide (IGO) nanosheets were used in UHPC. This type of economical graphene oxide improves the tensile strength and modulus of elasticity of UHPC. In addition to the mechanical properties, IGO improves the durability performance of UHPC, and to some extent prevents the absorption and penetration of fluids such as water in the concrete matrix. Furthermore, the microstructures of various specimens were investigated and compared by FESEM, along with the effects of IGO morphology on UHPC. It was found out that in comparison with the other specimens, the specimens with 0.06 % by weight of IGO showed the largest modulus of elasticity in the specimens tested in this study. Moreover, the test results shows that adding 0.01 %–0.1 % of IGO increases the 28-days compressive and flexural strengths of UHPC by 21.1–26.7 % and 11.5–32.7 %, respectively.

Impact of Electric-Arc Welding on The Mechanical Properties of AISI 1055 Medium Carbon Steel with Varied Gauge Diameters

Purpose: This paper investigated through experimentation, the impact of electric-arc welding processes on the mechanical properties of AISI 1055 steel medium carbon steel material with varied gauge diameters.
 Design/Methodology/Approach: The study used experimental and analytical methods to investigate the impact of electric arc welding on the mechanical properties of AISI 1055 Medium Carbon Steel. The test samples were prepared based on the standards of the American Iron and Steel Institute (AISI), with varied gauge diameters. Standard tensile tests were performed on the samples before welding and after welding, using a computer-interfaced Universal Tensile Testing Machine. Data obtained from the study was analyzed using graphs, tables and charts. Finally, the sets of results for both welded and unwelded specimens were compared to determine the impact that welding has on welded medium carbon steel components and structures.
 Findings: The data recorded by the computer-interfaced tensile test machine was used to plot and display, the stress-stain graphs for the various sets of samples. The results showed that the welding processes adversely affected the Ultimate Tensile Strength (UTS), Yield Strength, Elastic Modulus and Impact Strength of the samples studied; since all the samples studied had their initial values dropped after undergoing welding and testing. However, the strain of the samples increased after welding.
 Research Limitation/Implication: Although there are other methods and techniques of welding metals, this study adopted electric arc welding to weld the samples used for the study due to resource constraints.
 Practical Implication: The findings of this study also bring to the fore, the need for industry regulators to promulgate standards to regulate the welding of medium carbon steel and by extension, other industrial materials to preserve the natural properties of the materials.
 Originality/Value: This study introduced an important perspective to the testing of engineering materials by varying the gauge diameters (a key determinant of the dimensional specifications of the specimen), to obtain a comprehensive insight into the impact of electric-arc welding on the mechanical properties of the material.

Mechanical Properties and Fracture Resistance of 3D-Printed Polylactic Acid

Abstract 3D printing is a layer-by-layer deposition process, which results in highly anisotropic structures and contains interfaces. Complex shapes manufactured by 3D printing carry defects. Complete elimination of these defects and interfaces is not possible, and these defects degrade the mechanical properties. In the present study, mechanical properties of printed dog bone samples are quantified as a function of building parameters, in particular, filling patterns, raster angle, and orientation of build direction with respect to that of loading, in polylactic acid (PLA). The tensile strength of 3D-printed PLA is the same for hexagonal and linear pattern filling when the build direction is along thickness and width, and failure was initiated at the defects in the structure, while better overall toughness is offered by hexagonal pattern filling. Build direction along specimen gauge length gives very low tensile strength and toughness, and failure happens between the printing layers. To minimize the defects especially near the grip section, cuboid samples were first deposited and micro-machined by laser into dog bone shape to perform tension test. Tensile strength and elastic modulus of micro-machined samples are surprisingly lower, while failure strain is highest among line filling printed samples. Damage resistance was quantified in terms of work of fracture, and hexagonal filling provided better damage resistance than line filling patterns for conditions of 0 deg raster angle with respect to the crack, whereas line filling with 45 deg and 90 deg raster angle tolerated damage better than hexagonal filling.

Evaluating GFRP bars under axial compression and quantifying load-damage correlation

Fiber-Reinforced Polymer (FRP) bars have become widespread in the concrete construction industry because of their superior mechanical, physical, and durability properties. Although the tensile performance of FRP bars has been well studied, only a limited number of research projects have evaluated the compressive behavior of FRP bars due, among other reasons, to the need for a standard test method. This research aims to develop a test method to apply compression at the center of the FRP bar to avoid load eccentricity effects using a steel centering fixture with a plastic 3D-printed plug. To evaluate the ultimate compressive strength and elastic modulus, two different Glass FRP (GFRP) bars, with a 12.7 mm nominal diameter, but with two different length-to-diameter ratios of 2 and 4, were considered. The effect of 3D-printed plugs and cutting surface quality was also evaluated. The main contribution of this research is providing a straightforward test set-up for obtaining the compressive behavior of GFRP bars. The results showed that the compressive strength and elastic modulus of the tested GFRP bars are considerable in a way that the elastic modulus of the G1 bars in compression was equal to the tensile elastic modulus, so neglecting the effects of these bars in designing compressive members is too conservative.

Influence of silica fume and iron dust on mechanical properties of concrete

Construction sectors around the world are growing at a rapid pace. This growth is demanding more and more raw materials on daily basis. Supply is made mostly by consuming natural resources, whether it is limestone requirement for cement manufacture or sand and aggregates requirement for casting concrete. This research work attempts to address the said issue by utilizing industrial waste as substitutes for cement and sand in concrete. In this investigation, cement and fine aggregate are replaced with silica fume (0–15 %) and iron dust (0–30 %) respectively. A small amount (0–0.05 %) of superplasticizer was used to maintain the desired workability. Mechanical properties, such as compressive strength, flexural strength, split tensile strength, modulus of elasticity, and abrasion resistance were determined. Results indicate that Compressive, flexural, split tensile strength and modulus of elasticity increased by 29.40 %, 21.53 %, 16.44 %, and 7.23 % respectively, and abrasion value decreased by 11.05 % at 84 days for 10 % silica fume and 20 % iron dust replacement level.

Melt Electrowriting of Nylon-12 Microfibers with an Open-Source 3D Printer.

This study demonstrates how either a heated flat or cylindrical collector enables defect-free melt electrowriting (MEW) of complex geometries from high melting temperature polymers. The open-source "MEWron" printer uses nylon-12 filament and combined with a heated flat or cylindrical collector, produces well-defined fibers with diameters ranging from 33±4 to 95±3µm. Processing parameters for stable jet formation and minimal defects based on COMSOL thermal modeling for hardware design are optimized. The balance of processing temperature and collector temperature is achieved to achieve auxetic patterns, while showing that annealing nylon-12 tubes significantly alters their mechanical properties. The samples exhibit varied pore sizes and wall thicknesses influenced by jet dynamics and fiber bridging. Tensile testing shows nylon-12 tubes are notably stronger than poly(ε-caprolactone) ones and while annealing has limited impact on tensile strength, yield, and elastic modulus, it dramatically reduces elongation. The equipment described and material used broadens MEW applications for high melting point polymers and highlights the importance of cooling dynamics for reproducible samples.

Experimental statistical modeling of tensile properties and flexural stiffness of recycled high-density polyethylene (rHDPE) thermoplastic using response surface methodology (RSM)

The widespread use of thermoplastic polymer products, particularly high-density polyethylene (HDPE), in daily consumer goods has led to the generation and accumulation of large amounts of plastic waste. This waste poses a significant threat to the environment due to the challenges and limitations in managing plastic waste effectively. Establishing new large volume applications of recycled HDPE (rHDPE) would incentivize recycling by creating new revenue streams. Before rHDPE (specifically rHDPE-talc blends) can be used more heavily in lieu of or in addition to virgin HDPE (vHDPE), its material properties in relation to application temperatures must be better understood. This study focused on characterizing tensile and flexural properties of rHDPE-talc blends across broad talc filler content and temperature ranges. Experimentally, tensile strength, elastic modulus, storage modulus, and nominal yield strain data were collected. Tensile strength and elastic modulus were observed to increase with an increase in talc content and decrease with an increase in temperature. Conversely, yield strain was observed to decrease with an increase in talc content and increase with an increase in temperature. Response Surface Methodology (RSM) was applied using the Central Composite Design (CCD) statistical experimental design approach to study the stiffness and strength of rHDPE and the effects that temperature and talc filler content have on these mechanical properties. The surfaces generated in this analysis fit the data well, with coefficients of determination greater than 0.94 for all but one property, storage modulus, which was 0.80. The evaluation of model performance revealed that the surfaces yielded good correlation and statistical significance. The results provide useful relationships that can be considered for use in practical applications involving rHDPE-talc blends, including engineering applications.

Effects of mechanical recycling on the properties of glass fiber–reinforced polyamide 66 composites in automotive components

Abstract In this study, we aimed to reveal the effective reusability of waste generated during the injection molding process of polyamide 66 (PA66) reinforced with 30 wt% of short glass fiber (PA66-GF30) widely used in the automotive industry. PA66-GF30 was subjected to the three mechanical recycling cycles, including regranulation and reinjection molding steps, and the recycled materials obtained in each of these cycles were included at the ratios of 15, 20, 25, and 30 wt% to the virgin composite. Thermogravimetric analysis and differential scanning calorimeter analyses showed that the number of recycling cycles and recycled material content in the composite had no significant change in the thermal stability and crystallinity degree of the PA66-GF30. The average fiber length determined by optical microscope analysis shifted to lower values from 300–350 to 150–250 μm by increasing the number of recycling cycles and the recycled material content. The fact that the recycled material content in the composite exceeds 25 wt% and the recycling cycle is applied three times played a key role in changing the mechanical and melt flow behaviors of the composite. Tensile strength, elastic modulus, and impact energy slightly decreased while the elongation at break and melt flow index increased.

Material extrusion 3D printing of biodegradable composites reinforced with continuous flax fibers

Fabricating additively manufactured thermoplastic parts with increased load-bearing capacity using material extrusion, namely fused deposition modeling, requires the incorporation of continuous reinforcing fibers. In this study, composites of PLA matrix and continuous flax fibers were additively fabricated using a specially designed 3D printer with multiple deposition toolheads. Unidirectional tensile and flexural specimens with a component-like shape and a fiber volume fraction of up to 18% were fabricated. The mechanical properties were determined for four different composite and matrix layers arrangements. The tensile modulus of elasticity and strength values increased by 3.6 and 2.9 times, respectively, compared to the specimens without the reinforcing fibers. In contrast, the flexural modulus of elasticity improved by 2.4 times, while the flexural strength increased by 1.4 times. It was found that it is possible to influence the mechanical properties and the type of damage by changing the volume fraction of the fibers and the arrangement of the composite layers.

Sonochemical synthesis of lignin nanoparticles and their applications in poly (vinyl) alcohol composites

Lignin is a common and abundant byproduct of the pulp and paper industry and is generally burned to produce steam. Opportunities exist to acquire greater value from lignin by leveraging the properties of this highly conjugated biomacromolecule for applications in UV absorption and polymer reinforcement. These applications can be commercialized by producing value-added lignin nanoparticles (LNPs) using a scalable sonochemical process. In the present research, monodisperse LNPs have been synthesized by subjecting aqueous dispersions of alkali lignin to acoustic irradiation. The resulting particle size distribution and colloidal stability, as determined by dynamic light scattering, transmission electron microscopy and zeta potential analysis, of LNPs can be adjusted by varying the solution pH and ultrasonication energy. As-synthesized LNPs with a mean diameter of 204 nm were incorporated into poly (vinyl) alcohol (PVA) to prepare thin and flexible nanocomposite films using a simple solvent casting method. The addition of 2.5 wt% LNP increased the material's Sun Protection Factor up to 26 compared to 0 for neat PVA, while maintaining light transmission above 75 % in the visible spectra. In addition, the tensile strength and elastic modulus of the PVA nanocomposites improved by 47 % and 36 %, respectively. The presence of LNP also enhanced the thermal stability of the materials. Significantly, the proposed sonochemical process may be generally applicable to the synthesis of a range of naturally-derived LNPs for a variety of value-added applications.

The multi-objective optimization of material properties of 3D print onyx/carbon fiber composites via surrogate model

Composite materials play a prominent role in modern engineering. The emergence of composite material technology has brought about a profound impact on almost, if not all industries. The aerospace industry, for instance, benefits greatly from composite materials. With composites, aircraft weight can be reduced while the structural strength is maintained. As with other classes of materials, 3D printing technique allows composite parts of high complexity to be fabricated with great precision. Additionally, with 3D printing, mechanical properties of the resulted part can be accurately customized and controlled by means of varying matrix-reinforcement proportions. As the composite material can be indefinitely customized in 3D printing, it is crucial to evaluate the mechanical properties of the printed specimen. While testing of printed specimens is usually possible, endless production and testing of specimens not only takes time and resources but also leads to extensive experimental waste. In this study, an optimization-based technique is proposed to determine the optimal 3D printing material proportion in order to reduce the need of unwarranted experimental waste and improve the efficiency of composite material selection process. The study aims to investigate the properties of Onyx/Carbon fiber composite material and the optimization of the 3D printing configuration to achieve desirable mechanical properties. The effects of the number of carbon concentric fiber rings and the percentage of infill density of Onyx used in 3D printing were examined. ASTM D3039 tensile tests were performed to obtain mechanical properties of the printed specimen. Considering the values of tensile strength and modulus of elasticity of the printed material, the printing configurations were optimized using a multi-objective non-dominated sorting genetic algorithm II (NSGA-II) with the Kriging model for objective function estimation. From the proposed optimization technique, it has been found that the maximum tensile strength is attained when the number of concentric fiber rings is equal to 3 while the percentage of Onyx infill density falls in the range of 86–90. Contrarily, the modulus of elasticity is maximized when the number of concentric fiber rings is equal to 4 with the percentage of Onyx infill density in the range of 70–75.

Biocomposite films from banana flour/halloysite nanoclay/carvacrol: Preparation, characterization, and application on capsicum (Capsicum annuum) fruits

In this work, banana flour (BF)-based composite films were formulated by loading halloysite nanoparticles (HS) and essential oil carvacrol (CR). HS nanoclay was selected since it has abilities to improve the mechanical and water vapor barrier properties of the prepared films. CR was used since it demonstrates powerful antimicrobial activity against foodborne pathogens. Results reveal successful incorporation of HS and CR in the composite films that display an improved melting temperature (Tm) and rough surface. The water solubility of the films significantly reduced whereas the contact angle significantly improved with the impregnation of both HS and CR. The XRD diffractograms indicated pre-dominant amorphous characteristics of all the prepared films. These changes reflected well on the mechanical properties, wherein the tensile strength and Elastic modulus increased by ∼47% and ∼206%, respectively. The presence of HS and CR also reduced the films' water vapor transmission rate by about 62%. In addition, as a case study, BF/HS/CR dispersions were coated on a capsicum fruit to test their protecting ability. The incorporation of HS and CR in the BF-based biopolymeric matrix resulted in a significant reduction in the %weight loss, from 50.96 ± 2.40% (control: without coating) to 37.42 ± 3.75% (with the coating), along with an improvement in the firmness (N) from 5.04 ± 0.92 N (control: without coating) to 7.47 ± 0.25 N (with the coating), during 12 days of storage. The outcome promises BF/HS/CR based films and dispersions as natural food packaging materials to extend the shelf life of food systems.

The impact of esterified nanofibrillated cellulose content on the properties of thermoplastic starch/PBAT biocomposite films through ball-milling

To enhance the mechanical properties and interfacial compatibility of thermoplastic starch (TPS) highly filled poly(butylene adipate co-terephthalate) (PBAT) composite films, esterified NFC was innovatively fabricated and introduced into the composite system. The influences of NFC content and ball-milling treatment were thoroughly investigated. Interestingly, the amphiphilic esterified NFC provided a “bridge-like” effect between TPS and PBAT interfaces, which significantly improved the interfacial compatibility and mechanical properties. Notably, the tensile properties of the composite films reached their maximums at a 7 wt% NFC content, displaying a tensile strength of 6.2 MPa and an elastic modulus of 263 MPa. These values corresponded to a 59 % and 180 % increase, respectively, compared to the composition without NFC. More importantly, ball-milling contributed to uniform dispersion and surface activation of NFC, preventing starch retrogradation, and enhancing the tensile strength and elastic modulus by 30.3 % and 56.6 %, respectively. Additionally, the film exhibited excellent UV-blocking, foldable, writable, and transparent performance. These findings provide valuable data supporting the expanded applications of starch-based composite films.

Influences of 3D printing parameters on the mechanical properties of wood PLA filament: an experimental analysis by Taguchi method

This study investigates the effects of 3D printing parameters on the mechanical properties (predominantly tensile properties) of a commercial polylactic acid-based wood fiber composite material known as wood filament. The influence of printing parameters, including layer thickness, infill density, printing speed, and nozzle temperature on the mechanical properties, is studied, and the design of the experiment (DOE) is made through Taguchi L9 orthogonal array. The specimens for the tensile test are fabricated by the material extrusion (MEX) 3D printer, which is also known as fused deposition modeling (FDM) or fused filament fabrication (FFF). After conducting the tensile test, this research considers four significant outcomes: tensile strength, maximum load, elastic modulus, and elongation at break. Further analysis of the obtained results from mechanical testing is performed through analysis of variance (ANOVA) to determine the significance of each parameter on the mechanical properties. Moreover, prediction and optimization are conducted to verify the obtained results from the DOE. Furthermore, scanning electronic microscopy (SEM) is used to analyze the fracture zones, cracks, voids, and fiber/matrix adhesion of the FDM fabricated parts which demonstrates that the lower layer thickness provides better adhesion and fewer voids between successive layers and thus exhibits better mechanical performance.Graphical abstract

Tensile properties and sustainability assessment of vat photopolymerization 3D printed components with recovered plastic filler

AbstractRaw material production represents one of the major issues of additive manufacturing as it can be an expensive and environmentally impactful phase. One example is provided by the light-curing resins used in vat photopolymerization processes. To this purpose, this study aims at evaluating the use of recovered polyamide powders as filler for photocurable resins from different perspectives; to this purpose, tensile tests were performed in order to evaluate the effect of recovered powder content as filler on the mechanical properties of the resin. Furthermore, a scanning electron microscopy and computed tomography analyses were carried out to investigate the fracture mechanisms and dispersion of the filler within the resin. Finally, a life cycle assessment analysis was performed to evaluate the effect of different reused power contents as filler on the environmental impact of 3D printed components. Results showed that the use of recovered powder as filler for light-curing resin in vat photopolymerization 3D printing parts allows the obtaining of an improvement in terms of tensile strength and elastic modulus up to 62% and 107%, respectively. In addition, a reduction in environmental impacts up to 48% was obtained. A homogeneous dispersion of the particles within the resin was observed at the different filler contents investigated.

Material properties of spray‐dried cellulose nanocrystal reinforced homopolymer polypropylene composites

AbstractSpray‐dried cellulose nanocrystal (SDCNC) particles have attracted intense interest as reinforcements in polymer composites because of their unique physical and mechanical properties. This work aims to develop homopolymer polypropylene (HPP) composites with different loading levels of SDCNC particles (5, 10, 15, and 30 wt%) to understand their impact on composite mechanical, morphological, and thermal properties. The SDCNC‐reinforced HPP composites were manufactured using a C.W. Brabender bowl internal mixer with a masterbatch concept and an injection molding process. The mechanical, morphological, and thermal properties of the composites were investigated. Compared to pure HPP, the tensile, and flexural modulus of elasticity (MOE) of composites with 30 wt% SDCNC significantly increased by up to 67% and 49%. The impact strength of the composites with the absence of a compatibilizer significantly increased by up to 19%, which was attributed to the mechanical interlocking network established between SDCNC particles and HPP. Additionally, increasing SDCNC loading in the composites led to higher crystallization peak temperatures and increased the degree of crystallinity (especially at 30 wt% SDCNC content), indicating that the SDCNC particles can act as heterogeneous nucleating agents during the crystallization process. The thermal stability of the composite was slightly improved upon SDCNC introduction.Highlights With the incorporation of spray‐dried cellulose nanocrystal (SDCNC), the tensile modulus of elasticity (MOE), flexural MOE, and impact strength of filled homopolymer polypropylene (HPP) composites were significantly improved by up to 67%, 49%, and 19%, respectively. Mechanical interlocking network established between SDCNC and HPP contributed to the enhanced the impact strength. SDCNC particles can act as heterogeneous nucleating agents to promote the crystallization process of HPP. SDCNC particles slightly enhanced the thermal stability of HPP composite.

Experimental research on mechanical properties and elastic modulus of glass fiber reinforced concrete

By adding ordinary glass fiber and alkali resistant glass fiber into concrete, the development of axial compressive strength, axial tensile strength and elastic modulus of concrete are studied. The results show that with the increase of glass fiber, the axial compressive strength increases first and then decreases; the axial tensile strength increases; the elastic modulus decreases. The results show that glass fiber can improve the strength of concrete, and reduce the elastic modulus.

Effect of temperature on the compressibility behavior of glass fiber-bentonite mixture

Effect of temperature on the compressibility behavior of glass fiber-bentonite mixture