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This study aims to systematically experimental investigate the influence of infill-patterns (IPs) on specific mechanical responses of parts fabricated by fused deposition modeling (FDM). A poly-lactic-acid (PLA) feedstock filament is utilized in the manufacturing process. Furthermore, six types of infill-patterns (deposition angle), namely full honeycomb, rectilinear, triangular, fast honeycomb, grid, and wiggle, are designed and printed. In order to determine the mechanical properties of manufactured parts, tensile tests are carried out. The mechanical properties such as extension, stress, elongation, energy, and Young’s modulus are considered as objective functions. As a result, there is a direct correlation between mechanical properties and infill patterns. Thus, it is essential to select the best infill-pattern in terms of their applications, giving sufficient strength without overdoing time and cost. Based on the results, a triangular infill-pattern has a maximum value of ultimate tensile strength and E-module (15.4 and 534 MPa, respectively). On the other hand, the wiggle pattern is more flexible.

In engineering practice, fiber addition is a frequently used method to improve the tensile property of asphalt mixture. However, the optimum fiber type and dosage have not been determined by direct tensile tests. In this paper, monotonic tensile tests were conducted on three kinds of stone mastic asphalt (SMA13) mixtures, that is, granular-lignin-fiber-reinforced SMA (GFSMA), flocculent-lignin-fiber-reinforced SMA (FFSMA), and basalt-fiber-reinforced SMA (BFSMA) at different fiber dosages to probe the influence of fiber dosage on their tensile mechanical indexes (tensile strength, ultimate strain, elastic modulus, and strain energy density) and to determine the optimum dosage of each kind of fiber. The results showed that with the elevation of fiber dosage, the tensile strength, elastic modulus, and strain energy density of all three kinds of asphalt mixtures increased first and then decreased, while the ultimate strain increased constantly. The optimum dosage was 0.50 wt%, 0.45 wt%, and 0.50 wt% for granular lignin fiber, flocculent lignin fiber, and basalt fiber, respectively. On this basis, strain-controlled direct tensile fatigue tests were conducted on the three kinds of asphalt mixtures at the corresponding optimum fiber dosage. The results indicated that asphalt mixture reinforced with 0.50 wt% granular lignin fiber exhibited ideal direct tensile fatigue performance with respect to fatigue life and accumulative dissipated energy. Therefore, granular lignin fiber is recommended as the favorable fiber type, and its optimum dosage is 0.50 wt%. Moreover, scanning electron microscopy (SEM) demonstrated that the essence of the impact of fiber dosage and type on the tensile property of SMA is whether the reinforcement effect on the mixture matrix outweighs the negative effect of the defects between fiber and mixture matrix, or whether the reverse applies.

The 2195 aluminum alloy is widely used in cryogenic storage tanks for space vehicles, where it can reach a temperature of 20 K. In order to explore the reasons for the increased strength of 2195 aluminum alloys at cryogenic temperatures, uniaxial tensile tests were conducted in the range of 20 K–298 K. Tensile fracture was observed. In addition, the microstructures under different temperatures were observed using EBSD (electron back-scattered diffraction) and TEM (transmission electron microscopy) techniques, and the dislocation density of the material was quantitatively characterized using the modified Williamsone–Hall method based on XRD (X-ray diffraction) analysis. The results indicated that the ultimate strength increased at an increasing rate with the temperature decrease, while the elongation increase was insignificant. The fracture’s surface exhibited that dimple characteristics seemed to be unapparent while the quantity of tearing ridges was enhanced by the temperature decrease. Meanwhile, the fracture mode changed from ductile to brittle fracture. The microdeformation degree revealed by KAM images showed an aggravating trend, and the deformation tended to be more uniform. The increasingly enhanced dislocation density quantitatively revealed by the modified Williamsone–Hall method also proved this and that the increase in dislocations had a similar trend to that of tensile strength, which was furtherly revealed by TEM images. This indicated that the more regions are involved in deformation, the more dislocations are generated in the material during deformation, resulting in an increase in strength at cryogenic temperatures.

Mechanical and fracture behaviors of rocks are largely dependent on the rock structure and existing flaws. This study mainly focuses on the combined effects of bedding plane and void on the tensile mechanical behaviors of layered rock. Brazilian tensile tests accompanied by acoustic emission (AE) and image collecting testing were first conducted on layered rock-like material with different bedding plane inclination angles. The experimental results showed that Brazilian tensile strength (BTS) and accumulated AE energy decreased with the increasing bedding plane inclination angle. The failure patterns of testing specimen transformed from central failure to layer activation failure. The relationships between BTS values and accumulated AE energy can be fitted by a linear function. Based on the cohesive zone model, the effects of bedding plane strength and spacing were further investigated, and the effects of bedding plane strength and void size on tensile behaviors of numerical specimen containing void were discussed. The numerical results indicated that both bedding plane strength and spacing had strong influences on BTS values and failure patterns of numerical specimen. The existing void has a strong attenuation on tensile behavior of numerical specimen. The tensile mechanical behaviors were strongly influenced by bedding plane strength and void size.HighlightsThe relationships between BTS values and accumulated AE energy can be fitted by a linear function.Both bedding plane strength and spacing have strong influences on tensile behavior of numerical specimen.The numerical modelling of layered rock containing void was established and the effects of bedding plane strength and void size were discussed.

With 22 mnb5 St16 and ordinary steel as the research object, under the conditions of medium frequency spot welding connection plate welding, solder joint for the electric logging under shear load test, determination of solder joints, solder joint and away from the solder joint around the base of strain, according to measurement data analysis of solder joints and the deformation regularity of parent metal. The test results show that the strain in the spot welding joint distribution is uneven, the center of the welding strain is small, large deformation mainly exist in the heat affected zone, near the solder heat affected zone is the main area prone to give in. Away from the solder joint area of the parent metal, the influence of solder joint is small, mainly tensile strain, and strain as the load increases, solder joint strain is negative, the center is linear, and basic antisymmetric location of strain values different test points.

To enhance the moisture damage performance of hot mix asphalt (HMA), treating the aggregate surface with a suitable additive was a more convenient approach. In this research, two types of aggregate modifiers were used to study the effect of moisture damage on HMA. Three different aggregate sources were selected based on their abundance of use in HMA. To study the impact of these aggregate modifiers on moisture susceptibility of HMA, the indirect tensile strength test and indirect tensile modulus test were used as the performance tests. Moisture conditioning of specimens was carried out to simulate the effect of moisture on HMA. The prepared samples’ tensile strength ratio (TSR) and stiffness modulus (Sm) results indicated a decrease in the strength of the HMA after moisture conditioning. After treating the aggregate surface with additives, an improvement was seen in dry and wet strength and stiffness. Moreover, an increasing trend was observed for both additives. The correlation between TSR and strength loss reveals a strong correlation (R2 = 0.7219). Also, the two additives indicate increased wettability of asphalt binder over aggregate, thus improving the adhesion between aggregate and asphalt binder.

The Fused Filament Fabrication (FFF) method is an additive technology that is used for the creation of prototypes within Rapid Prototyping (RP) as well as for the creation of final components in piece or small-series production. The possibility of using FFF technology in the creation of final products requires knowledge of the properties of the material and, at the same time, how these properties change due to degradation effects. In this study, the mechanical properties of the selected materials (PLA, PETG, ABS, and ASA) were tested in their non-degenerate state and after exposure of the samples to the selected degradation factors. For the analysis, which was carried out by the tensile test and the Shore D hardness test, samples of normalized shape were prepared. The effects of UV radiation, high temperature environments, high humidity environments, temperature cycles, and exposure to weather conditions were monitored. The parameters obtained from the tests (tensile strength and Shore D hardness) were statistically evaluated, and the influence of degradation factors on the properties of individual materials was assessed. The results showed that even between individual manufacturers of the same filament there are differences, both in the mechanical properties and in the behavior of the material after exposure to degradation effects.

Ultra-high-performance concrete (UHPC) with a low steel fiber volume fraction offers lower material costs than UHPC with typical steel fiber volume fractions, and has the potential to mitigate the ductility degradation of rebar-reinforced UHPC (R-UHPC). This study explores the reinforcement effect on the tensile behavior of UHPC with a low fiber volume fraction with the aim of facilitating more cost-efficient UHPC applications. The axial tensile behavior of 30 UHPC specimens with low fiber volume fractions at different reinforcement ratios was tested through direct tensile tests. The findings indicate that adopting UHPC with a low fiber volume fraction can significantly mitigate the ductility deterioration of rebar-reinforced UHPC (R-UHPC), and both increasing the reinforcement ratio and decreasing the fiber volume fraction contribute to the improvement in ductility. The failure modes of R-UHPC are determined by the ratio of reinforcement ratio and fiber volume fraction, rather than a single parameter, which also means that R-UHPC with different parameters may correspond to different methods to predict tensile load-bearing capacity. For UHPC with a fiber volume fraction low to 0.5%, incorporating steel rebars gives superior multi-crack cracking behavior and excellent capacity to restrict the maximum crack width. Increasing the fiber volume fraction from 0.5% to 1.0% at the same reinforcement ratio will yield little benefit other than an increase in tensile load-bearing capacity.

The poor mechanical strength of tissue-engineered auricular cartilage which is possibly due to the lack of perichondrium limits its application in auricular reconstruction surgery. However, there is insufficient research and no reliable data to support this. This study aims to investigate the contribution of perichondrium to the mechanical strength of auricular cartilage under loading. Rabbit auricular cartilage was harvested and classified into two groups. The perichondrium was removed in Group A and was left intact in Group B. Young’s modulus, stress relaxation slope, and relaxation amout were analyzed through tensile and compressive tests using a material testing machine. Group B exhibited significantly higher Young’s modulus in both the tensile and compressive tests (p < 0.05), lower relaxation slope (p < 0.05 in tensile test, p = 0.65 in compressive test), and lower relaxation amout (p < 0.05 in tensile test, p < 0.01 in compressive test). Our results showed that the perichondrium has a definite contribution to the mechanical properties of ear cartilage. This study may provide new insights to researchers focusing on improving the mechanical strength of tissue-engineered auricular cartilage.

There is no unified method for deriving the tensile properties of fiber-reinforced ultra-high-performance cementitious composites (UHPCC). This study compares the most common material tests based on a large series of laboratory tests performed on a self-developed UHPCC mixture. The cementitious matrix, with a compressive strength of over 150 MPa and a matrix tensile strength of 8–10 MPa, was reinforced with 2% by volume of 15 mm long and 0.2 mm diameter straight high-strength steel microfibers. Over 100 uniaxial tensile tests were performed on three test configurations using cylindrical cores drilled out from larger prismatic specimens in three perpendicular directions. In addition to uniaxial tests, flexural tests on prismatic elements and flexural tests on thin plates were conducted, and the tensile properties were derived through digital image correlation (DIC) measurements and inverse analysis. Furthermore, splitting tensile tests on cylindrical specimens were employed to ascertain the tensile properties of the matrix. The outcomes of the diverse laboratory tests are presented and discussed in detail. The relationships between crack width and deflection in the context of flexural tests were developed and presented. In conjunction with compression tests and modulus of elasticity tests, the constitutive law is presented for the investigated materials.