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The purpose of this paper is to conduct a laboratory investigation on measuring the tensile strength of recycled concrete using a double punch test. Furthermore, one of the main goals of this study is to compare the tensile and compressive strengths of recycled concrete samples.

Recycled concrete samples were made with variables such as aggregate type (natural stone and aggregate recycled concrete), different water-to-cement ratios and different treatment conditions in the first stage. In the next stage, the double punch test was performed on them, and finally the results obtained from experiments were analyzed and investigated.

According to the above tests, it was concluded that: first, according to the laboratory results, the strength of concrete containing recycled aggregates becomes closer to the strength of concrete containing natural aggregates whenever the water-to-cement ratio is higher. Second, upon investigating the treatment conditions, it was observed that the treatment had a greater effect on the strength of the recycled concrete. However, this effect was less tangible in tensile strength. Third, upon investigating the results of tensile strength, it can be said that the Barcelona test results were closer to the direct tensile test results compared to the Brazilian test results. This indicates the higher viability of Barcelona’s test results. Fourth, the results obtained from the Barcelona tensile test for recycled concrete were closer to the results of the direct tensile test compared to the concrete containing natural aggregates, which suggests that the Barcelona test is more suitable as a tensile test for recycled concrete. Fifth, the effects of various factors on tensile strength were somewhat less compared to the compressive strength, although very close. Sixth, the relationships provided by the regulation for concrete tensile strength on compressive strength were highly inconsistent with the results obtained from the direct tensile test, for which the consistency was higher for concrete containing natural aggregates compared to recycled concrete. Seventh, the dispersion of results obtained from tensile tests was higher for recycled concrete compared to concrete containing natural aggregates, but lesser of this dispersion was observed in the compressive strength.

According to the laboratory results, the strength of concrete containing recycled aggregates becomes closer to the strength of concrete containing natural aggregates whenever the water-to-cement ratio is higher. Upon investigating the treatment conditions, it was observed that the treatment had a greater effect on the strength of the recycled concrete. However, this effect was less tangible in tensile strength. On the basis on the results of the tensile strength, it can be said that the Barcelona test results were closer to the results of the direct tensile test compared to those of the Brazilian test. This indicates the higher viability of Barcelona’s test results. The results obtained from the Barcelona tensile test for recycled concrete were closer to the results of direct tensile test compared to the concrete containing natural aggregates, which suggests that the Barcelona test is more suitable as a tensile test for recycled concrete. The effects of various factors on tensile strength were somewhat less compared to the compressive strength, although very close. The relationships provided by the regulation for concrete tensile strength on compressive strength were highly inconsistent with the results obtained from the direct tensile test, for which the consistency was higher for concrete containing natural aggregate compared to recycled concrete. The dispersion of results obtained from tensile tests was higher for recycled concrete compared to concrete containing natural aggregate, but lesser of this dispersion was observed in the compressive strength.

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.

This paper presents an experimental investigation in establishing the relationship between FDM process parameters and tensile strength of polycarbonate (PC) samples using the I-Optimal design.

I-optimal design methodology is used to plan the experiments by means of Minitab-17.1 software. Samples are manufactured using Stratsys FDM 400mc and tested as per ISO standards. Additionally, an artificial neural network model was developed and compared to the regression model in order to select an appropriate model for optimisation. Finally, the genetic algorithm (GA) solver is executed for improvement of tensile strength of FDM built PC components.

This study demonstrates that the selected process parameters (raster angle, raster to raster air gap, build orientation about Y axis and the number of contours) had significant effect on tensile strength with raster angle being the most influential factor. Increasing the build orientation about Y axis produced specimens with compact structures that resulted in improved fracture resistance.

The fitted regression model has a p-value less than 0.05 which suggests that the model terms significantly represent the tensile strength of PC samples. Further, from the normal probability plot it was found that the residuals follow a straight line, thus the developed model provides adequate predictions. Furthermore, from the validation runs, a close agreement between the predicted and actual values was seen along the reference line which further supports satisfactory model predictions.

This study successfully investigated the effects of the selected process parameters - raster angle, raster to raster air gap, build orientation about Y axis and the number of contours - on tensile strength of PC samples utilising the I-optimal design and ANOVA. In addition, for prediction of the part strength, regression and ANN models were developed. The selected ANN model was optimised using the GA-solver for determination of optimal parameter settings.

The proposed ANN-GA approach is more appropriate to establish the non-linear relationship between the selected process parameters and tensile strength. Further, the proposed ANN-GA methodology can assist in manufacture of various industrial products with Nylon, polyethylene terephthalate glycol (PETG) and PET as new 3DP materials.

This paper aims to evaluate the mechanical behaviour of polycarbonate/acrylonitrile butadiene styrene (PC/ABS) filaments for fusion filament fabrication (FFF). PC/ABS have emerged as a promising material for FFF due to their excellent mechanical properties. However, the optimal processing conditions and the effect of the blending ratio on the mechanical properties of the resulting workpieces are still unclear.

A statistical factorial matrix was designed, including infill pattern, printing speed, nozzle size, layer height and printing temperature as factors (with three levels). A total of 810 workpieces were printed using PC/ABS blends filament with the FFF. The workpieces’ finishing and mass were evaluated. Tensile tests were performed. Analysis of variance was performed to determine the main effects of the processing conditions on the mechanical properties.

The results showed that the PC/ABS (70/30) exhibited higher tensile. Tensile rupture corresponded to 30% of the tensile strength. The infill pattern showed the highest contribution to the responses. The concentric pattern showed higher tensile strength. Tensile strength and mass ratio demonstrated the influence of mass on tensile strength. The influence of printing parameters on deformation depended on the blend proportions. Higher printing speed and lower layer height provided better quality workpieces.

This study has implications for the design and manufacturing of three-dimensional printed parts using PC/ABS filaments. An extensive experimental matrix was applied, aiming at a complete understanding of mechanical behavior, considering the main printing parameters and combinations not explored by literature.

The purpose of this study is to clarify both tensile and shear strength for self-drilling screws, which are manufactured from high-strength, martensitic-stainless and austenitic stainless-steel bars, and the load-bearing capacity of single overlapped screwed connections using steel sheets and self-drilling screws at elevated temperatures.

Tensile/shear loading tests for the self-drilling screw were conducted to obtain basic information on the tensile and shear strengths at elevated temperatures and examine the relationships between both. Shear loading tests for the screwed connections at elevated temperatures were conducted to examine the shear strength and transition of failure modes depending on the test temperature.

The tensile and shear strengths as well as the reduction factors at the elevated temperature for each steel grade of the self-drilling screw were quantified. Furthermore, either screw shear or sheet bearing failure mode depending on the test temperature was observed for the screwed connection.

The transition of the failure modes for the screwed connection could be explained using the calculation formulae for the shear strengths at elevated temperatures, which were proposed in this study.

This paper aims to explore the effect of bed temperature, primary layer thickness and infill pattern (rectilinear, honeycomb, triangular) on the mechanical properties of tensile strength and bending strength of 3D printed parts.

Samples in accordance to various ASTM standards were printed by fused deposition modelling (FDM) method by varying the various input paramaters such as bed temperature, primary layer thickness and infill pattern (rectilinear, honeycomb, triangular). Tensile and bending testing was carried out on the printed parts, and post to the testing, fractography has been carried out using scanning electron microscope.

With increase in bed temperature tensile strength and flexural strength first increases then decreases. With the increase in primary layer thickness, tensile strength and flexural strength increase. With regard to infill patterns, triangular and honeycomb exhibit better tensile strength and better flexural strength.

The 3D printing is increasingly becoming important for manufacturing of engineering parts, determining the process parameters which could result in better mechanical and physical properties shall certainly help designers and manufacturers globally.

This work elucidates the effect of various process parameters of FDM on tensile and flexural properties of the samples.

The correlations between mechanical behaviour, tensile strength, and rock parameters of metasedimentary rock samples in Karak, Pahang’s New Austrian Tunnelling Method (NATM) were statistically evaluated from the rock mechanic laboratory works at the selected sections around 2,000 m of the tunnel (named as NATM-1). According to a statistical analysis, lithotypes, geological structures, and region geology have a significant impact on the mechanical behaviour of the metasedimentary rock. In the Brazilian test, the fracture behaviour of the disc specimens was highly related to the reliability and precision of the experimental data by validations of methods. In this work, the impact of different loading methods and rock lithotypes on the failure mechanism of Brazilian discs was examined utilising five different metasedimentary rock types and three different loading methods. During the loading operation, the strain and displacement fields of the specimens were recorded and evaluated using a computerised strain gauge system. The rock types, according to experimental data, have a significant impact on the peak load and deformation properties of Brazilian discs. With the method below, tensile strength point of a disc specimen is clearly regulated by the material stiffness and tensile–compression ratio. Seismic occurrences have had a substantial impact on changing the rock and exerting forces that may affect its mechanical characteristics as well as its vulnerability to weathering effects or discontinuities. As a result, the goal of this study is to look into the connection between rock mechanics and metasedimentary rock stress analysis in NATM-1, Karak, Pahang.

The implications of metallic biomaterials involve stress shielding, bone osteoporosis, release of toxic ions, poor wear and corrosion resistance and patient discomfort due to the need of second operation. This study aims to use additive manufacturing (AM) process for fabrication of biodegradable orthopedic small locking bone plates to overcome complications related to metallic biomaterials.

Fused deposition modeling technique has been used for fabrication of bone plates. The effect of varying printing parameters such as infill density, layer height, wall thickness and print speed has been studied on tensile and flexural properties of bone plates using response surface methodology-based design of experiments.

The maximum tensile and flexural strengths are mainly dependent on printing parameters used during the fabrication of bone plates. Tensile and flexural strengths increase with increase in infill density and wall thickness and decrease with increase in layer height and wall thickness.

The present work is focused on bone plates. In addition, different AM techniques can be used for fabrication of other biomedical implants.

Studies on application of AM techniques on distal ulna small locking bone plates have been hardly reported. This work involves optimization of printing parameters for development of distal ulna-based bone plate with high mechanical strength. Characterization of microscopic fractures has also been performed for understanding the fracture behavior of bone plates.

The purpose of this paper is to study the effects of these major parameters, including layer thickness, deposition velocity and infill rate, on product’s mechanical properties and explore the quantitative relationship between these key parameters and tensile strength of the part.

A VHX-1000 super-high magnification lens zoom three-dimensional (3D) microscope is utilized to observe the bonding degree between filaments. A temperature sensor is embedded into the platform to collect the temperature of the specimen under different parameters and the bilinear elastic-softening cohesive zone model is used to analyze the maximum stress that the part can withstand under different interface bonding states.

The tensile strength is closely related to interface bonding state, which is determined by heat transition. The experimental results indicate that layer thickness plays the predominant role in affecting bonding strength, followed by deposition velocity and the effect of infill rate is the weakest. The numerical analysis results of the tensile strength predict models show a good coincidence with experimental data under the elastic and elastic-softened interface states, which demonstrates that the tensile strength model can predict the tensile strength exactly and also reveals the work mechanism of these parameters on tensile strength quantitatively.

The paper establishes the quantitative relationship between main parameters including layer thickness, infill rate and deposition velocity and tensile strength for the first time. The numerically analyzed results of the tensile strength predict model show a good agreement with the experimental result, which demonstrates the effectiveness of this predict model. It also reveals the work mechanism of the parameters on tensile strength quantitatively for the first time.

Fused deposition modeling (FDM) is being increasingly used in automotive and aerospace industries because of its ability to produce specimens having difficult geometrical shape. However, owing to lack of critical information regarding the reliability and mechanical properties of FDM-printed parts at various designs, the use of 3D printed parts in these industries is limited. Therefore, the purpose of this paper is to investigate the impact of process parameters of FDM on the tensile strength of open-hole specimen printed using in-house-fabricated polylactic acid (PLA).

In the present study, three process parameters, namely, raster angle, layer thickness and raster width, are selected for investigation of tensile strength. To produce the tensile specimens in the FDM machine, the PLA filament is used which is fabricated from PLA granules using a single-screw extruder. Further, the experimental values are measured and critically analysed. Failure modes under tests are studied using scanning electron microscopy (SEM).

Results indicate that the raster angle has a significant effect on the tensile strength of open-hole tensile specimen. Specimens built with 0° raster angle, 200-µm layer thickness and 500-µm raster width obtained maximum tensile strength.

In this work, a new concept of testing a plate that has a rectangular shape and a circular hole at the centre is tested. Open-hole tensile test standard ASTM D5766 has been implemented for the first time for the FDM process.