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The tensile behavior of additively manufactured nylon-based carbon fiber-reinforced composites (CFRP) is an important criterion in aerospace and automobile structural design. So, this study aims to evaluate and validate the tensile stiffness of printed CFRP composites (low- and high-volume fraction fiber) using the volume average stiffness (VAS) model in consonance with experimental results. In specific, the tensile characterization of printed laminate composites is studied under the influence of raster orientations and process-induced defects.

CFRP composite laminates of low- and high-volume fraction carbon fiber of different raster orientations (0°, ± 45° and 0/90°) were fabricated using the continuous fiber 3D printing technique, and tensile characteristics of laminates were done on a universal testing machine with the crosshead speed of 2 mm/min. The induced fracture surface of laminates due to tensile load was examined using the scanning electron microscopy technique.

The VAS model can predict the tensile stiffness of printed CFRP composites with different raster orientations at an average prediction error of 5.94% and 10.58% for low- and high-volume fiber fractions, respectively. The unidirectional CFRP laminate composite with a high-volume fraction (50%) of carbon fiber showed 50.79% more tensile stiffness and 63.12% more tensile strength than the low-volume fraction (26%) unidirectional composite. Fiber pullout, fiber fracture and ply delamination are the major failure appearances observed in fracture surfaces of laminates under tensile load using scanning electron microscopy.

This investigation demonstrates the novel methodology to study specific tensile characteristics of low- and high-volume fraction 3D printed CFRP composite.

The tensile test is one of the fundamental experiments used to evaluate material properties. Simulating a tensile test can be a replacement of experiments to determine mechanical parameters of a continuous material. The paper aims to discuss these issues.

This research uses a new approach to model a tensile test of a high-carbon steel on the basis of discrete element method (DEM). In this research, the tensile test specimen was created by using a DEM packing theory. The particle-particle bond model was used to establish the internal forces of the tensile test specimen. The particle-particle bond model was first tested by performing two-particle tensile test, then was adopted to simulate tensile tests of the high-carbon steel by using 3,678 particles.

This research has successfully revealed the relationships between the DEM parameters and mechanical parameters by modelling a tensile test. The parametric study demonstrates that the particle physical radius, particle contact radius and bond disc radius can significantly influence ultimate stress and Young’s modulus of the specimen, whereas they slightly impact elongation at fracture. Increasing the normal and shear stiffness, the critical normal and shear stiffness can enable the increase of ultimate stress, however, up to maximum values.

To improve the particle-particle bond model to simulate a tensile test for high-carbon steel, the damping factors for compensating energy loss from transition of particle motions and failure of bonds are required.

This work reinforces the knowledge of applying DEM to model continuous materials.

This research illustrates a new approach to model a tensile test of a high-carbon steel on the basis of DEM.

Some of the basic mechanical characteristics such as tensile, bending, shear, compression, and surface properties of cotton knitted fabrics after a durable flame‐retardant finishing, were studied by the objective‐evaluation method developed by Kawabata and Niva using the KES‐F system. In addition, properties such as bursting strength, drape and sewability were studied in order to further explore the influence of this treatment on the fabrics. All treated fabrics were flame‐retardant but their mechanical properties showed changes as a result of the above finishing. More specifically, a significant reduction in the bending and shear properties was recorded, which suggests that the flame‐retardant finishing primarily affects the above characteristics.

This study aims at designing consistent and durable concrete by making use of waste materials. An investigation has been carried out to evaluate the performance of conventional and optimal concrete (including 5% GP) at high temperatures for different exposure times.

An experimental work is carried out to compare the conventional and optimal concrete with respect to weight loss, mechanical strength characteristics (compressive, tensile and flexural) after exposed to 100, 200 and 300 °C with 1, 2 and 3 h duration of exposure followed by cooling in furnace for 24 h and then air cooling.

The workability of granite powder modified concrete decreases as percentage of replacement increases. Compressive, tensile and flexural strengths all increased at 100 °C when compared to strength characteristics at normal temperature, regardless of the exposure conditions, and there was no weight loss noticed. For 200 and 300 °C, the strengths were decreased compared to normal temperature and an elevated temperature of 100 °C, as weight loss of concrete specimens are observed to be decreased at these temperatures. So, the optimum elevated temperature can be concluded as 100 °C.

Incorporating pozzolanic binder (granite powder) as cement replacement subjecting to elevated temperatures in an electric furnace is the research gap in this area. Many of the works were carried out replacing GP for fine aggregate at normal temperatures and not at elevated temperatures.

Nowadays, a rotary friction welding method is accepted in many industries, particularly for joining dissimilar materials as a mass production process. It is due to advantages like less material waste, low production time and low energy expenditure. The effect of the change in carbon contents in steel is studied experimentally in the rotary friction welding process, and a statistical model is developed. The Grey Taguchi method gives the single parameters optimization for all output responses. The paper aims to discuss these issues.

An experimental setup was designed and produced to achieve the multi-response in single optimum parameters through Grey relational analysis. A continuous/direct drive rotary friction welding process is chosen in which transition from friction to the forging stage can be achieved automatically by applying a break. In this experimentation, high carbon and low carbon work-pieces with different carbon percentage were welded with rotary friction welding. Response tensile strength and micro-hardness of the design of the experiment are used to analyze the results.

The optimization of parameters has been performed with Grey relational analysis, and optimum parameters are friction pressure 40 kg/cm², forging pressure 100 kg/cm² and speed 1,120 rpm. GRA optimum parameters give 56.04 and 82.16 percent improvement in Tensile strength and micro-hardness, respectively.

High carbon steel (En-31) and low carbon steel (SAE-1020) are used in so many industrial applications. These materials are mostly used in the process like manufacturing, metallurgy, machinery, agricultural, etc. These practical applications have brought forward definite and notable economic benefits.

It provides a new framework to investigate the problems where multiple input machining variables and various output responses are obtained in single optimized parameters.

The reinforced concrete open-web sandwich slab is composed of upper rib, lower rib, surface plate and shear key and was applied to long-span structure crossing at 18–30 m. The shear-bearing capacity of shear key, having vital effects on the slab’s bearing capacity, is analysed to present its calculation formula used for the engineering application of the slab.

The shear-bearing capacity of shear key is analysed by the strut-and-tie model and the benchmark model established by the finite element method. Furthermore, the design formula of its shear capacity is given by the parametric analysis of FEM to adjust the result of the strut-and-tie model, using multivariate linear regression analysis of these parameters.

The calculation result of the benchmark model is compared with those of the strut-and-tie model and the standard formula, which indicates that the result of the strut-and-tie model is closer to that of the benchmark model than that of the standard formula. Moreover, the parametric analysis of the finite element model indicates that the volume–stirrup ratio of the shear key and the compression strength of the concrete have lesser effect on the shear capacity compared with the longitudinal reinforcement ratio and the shear-to-span ratio of the shear key and the relative section height of the rib.

The shear capacity of the shear key is provided in the paper by combining the finite element method and the strut-and-tie model, which is different from the calculation of the shear key in local codes and Chinese code, based on the theory of short corbel and the experiment of member. Furthermore, the formula of the shear capacity could be employed in the design and construction of the RC open-web sandwich slab, mainly used in the public and industrial multi-story building with long span to save the dwindling land resource currently.

The purpose of this study is the 16-fold recycling process effect of VZH159 nickel alloy powder on its features and characteristics of the printed material obtained by selective laser melting (SLM). Chemical composition, content of gas impurities, powder grading, pore volume fraction and surface morphology of powder particles, structure and properties of SLM material, surface roughness and deviations from specified geometry of the test samples were investigated.

The experiment’s method procedure presumes the use of only recycled powder without adding any virgin powder at each build cycle. To avoid powder sloughing because of incomplete filling of the build space, a print area delimiter was used. For all manufactured samples, hot isostatic pressing was carried out in an ASEA Quintus-16 facility. Heat treatment was carried out in air furnaces. Structure investigations were carried out on a Leica DMIRM metallographic complex. Microstructure studies were carried out on a Verios 460 scanning electron microscope with X-ray microanalysis.

With the number of recycling stages, an increase in oxygen content is observed in the powder, which leads to an increment for oxides in the printed material. The 16-fold recycling does not have a significant effect on the features of the powder itself and the printed material if the build space is filled with manufacturing parts by no more than 20%.

The creep rupture strength of the SLM material, which appears to be a sensitive characteristic to the quality of the applied powder, does not change in the printed material after all stages of powder recycling as well.

It is possible to assess the plastic strain associated with yielding under a two‐dimensional stress system X, Y of a disk, by accepting the shear strain energy as the criterion of yielding, and assuming that the principal plastic strains x, y and z for a general stress system of principal stresses X, Y and Z may be represented by

Examines the effects of directional variations in woven fabric properties on the behaviour of fabrics as they are plied and sewn together to form a seam. This is an important practical consideration, since garment manufacturing frequently involves the sewing of two fabric plies of completely different and constantly changing bias angles — none of which is along the grain line. Examines the variations in the properties of five woven materials, all lightweight and commonly used in women's summer apparel. The Kawabata Evaluation System (KES) was used to measure the mechanical and surface properties of strips, cut at different angles, from the test materials. To investigate the effect of orientation on seam quality, two plies cut from the same fabric but at different angles were sewn together under selected conditions. The resulting seams were characterized for seam quality using AATCC standards.

The purpose of this study, most recent advancements in threedimensional (3D) printing have focused on the fabrication of components. It is typical to use different print settings, such as raster angle, infill and orientation to improve the 3D component qualities while fabricating the sample using a 3D printer. However, the influence of these factors on the characteristics of the 3D parts has not been well explored. Owing to the effect of the different print parameters in fused deposition modeling (FDM) technology, it is necessary to evaluate the strength of the parts manufactured using 3D printing technology.

In this study, the effect of three print parameters − raster angle, build orientation and infill − on the tensile characteristics of 3D-printed components made of three distinct materials − acrylonitrile styrene acrylate (ASA), polycarbonate ABS (PC-ABS) and ULTEM-9085 − was investigated. A variety of test items were created using a commercially accessible 3D printer in various configurations, including raster angle (0°, 45°), (0°, 90°), (45°, −45°), (45°, 90°), infill density (solid, sparse, sparse double dense) and orientation (flat, on-edge).

The outcome shows that variations in tensile strength and force are brought on by the effects of various printing conditions. In all possible combinations of the print settings, ULTEM 9085 material has a higher tensile strength than ASA and PC-ABS materials. ULTEM 9085 material’s on-edge orientation, sparse infill, and raster angle of (0°, −45°) resulted in the greatest overall tensile strength of 73.72 MPa. The highest load-bearing strength of ULTEM material was attained with the same procedure, measuring at 2,932 N. The tensile strength of the materials is higher in the on-edge orientation than in the flat orientation. The tensile strength of all three materials is highest for solid infill with a flat orientation and a raster angle of (45°, −45°). All three materials show higher tensile strength with a raster angle of (45°, −45°) compared to other angles. The sparse double-dense material promotes stronger tensile properties than sparse infill. Thus, the strength of additive components is influenced by the combination of selected print parameters. As a result, these factors interact with one another to produce a high-quality product.

The outcomes of this study can serve as a reference point for researchers, manufacturers and users of 3D-printed polymer material (PC-ABS, ASA, ULTEM 9085) components seeking to optimize FDM printing parameters for tensile strength and/or identify materials suitable for intended tensile characteristics.