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Thermal shock resistance and mechanical reliability of aluminum nitride (AlN) ceramic substrates are essential in electronic device modules. In this study, the thermal shock behavior of AlN doped with aluminum - yttrium oxide (Al - Y 2 O 3) was explored. The results indicate that adding Al to AlN ceramics increases its flexural strength, thermal conductivity, and thermal expansion coefficient. The microcracks caused by thermal mismatch between the AlN matrix and the secondary phases relieved internal stress, thereby improving thermal shock resistance of AlN ceramics. Furthermore, the addition of Al isolates and homogenizes the secondary phases, resulting in a more uniform microstructure and strengthened grain boundaries, which enhance the flexural strength, Weibull modulus, and thermal shock resistance. After introducing 0.5 wt% Al, the Weibull modulus of AlN ceramics increased by 73.37 %, and their critical thermal shock temperature difference exceeded 800 °C, with a maximum residual strength of 488.01 ± 48.26 MPa at 600 °C. Overall, an appropriate amount of Al improves the reliability and thermal shock resistance of AlN ceramics. [ABSTRACT FROM AUTHOR]

The effects of geometric scaling on the strain rate sensitivity of unidirectional and [+45/−45]s laminates under uniaxial tensile loading has been investigated experimentally. Two material systems, Toray T800/3900-2B carbon/epoxy unitape and Newport NB321/7781 fiberglass/epoxy fabric, were used in the study. The nominal strain rates investigated ranged from quasi-static (0.0002 s−1) to moderate strain rates of 50 s−1 across the scaled specimen geometries. The geometric scaling effects at different strain rates were quantified in terms of the Weibull modulus. At each strain rate, the average failure stress of [0]4 carbon, [0]4 fiberglass, and [±45]s fiberglass showed a declining trend with increasing specimen size. However, the percentage of the strength reduction was less significant at higher strain rates compared to the quasi-static strain rate. In contrast to the other stacking sequences, [+45/−45]s carbon specimens showed a maximum percentage in strength reduction at a high strain rate compared to the quasi-static strain rate, indicating increased scaling effect with strain rate. The magnitude of Weibull modulus (m) for the specimens increased with strain rate indicating diminishing scaling effects, while [+45/−45]s carbon specimens exhibited an opposite trend. [ABSTRACT FROM AUTHOR]

The main objective of this study is to enhance the interfacial adhesion between Kevlar fiber‐reinforced epoxy composite for a single lap joint. This has been achieved by performing various chemical treatments on Kevlar fiber. Moreover, the nanofiller‐added epoxy matrices were also used for investigating its potentiality in a single lap joint. A thorough comparison has been made among various chemical treatments based composite and modified epoxy matrix composite. The tensile strength of similar and dissimilar single lap joints was investigated through experiments and was analyzed by SEM, XRD, and Weibull model. It was perceived that the tensile shear strength and Weibull modulus of the treated similar Kevlar lap joint were 21.45% and 40.18% higher than the similar nanocomposite joint; also, it has been found that an increment of about 79.8% and 76.64% with that of untreated similar Kevlar joint. Furthermore, the failure progression of optimized joints was evaluated by acoustic emission (AE) monitoring. Highlights: Interfacial adhesion study of Kevlar fiber with matrix in single lap joint.Kevlar surface modification and epoxy modified by nanocomposites were used.The lap shear strength of similar and dissimilar single lap joint composites.SEM, XRD, and Weibull analysis and AE monitoring were used for this research.Chemical treatments on Kevlar fiber have enhanced the interfacial adhesion. [ABSTRACT FROM AUTHOR]

Recently moving towards the usage of sustainable and renewable construction materials, the badminton strings are identified as alternate material for commercial fibers. These recycled badminton strings once discarded from the racquets become a waste and cannot be reused. Hence investigation of the interphase bond behavior of these fibers with the cement and epoxy polymer matrix plays a major role. Therefore, the pullout mechanism between the fibers with the epoxy matrix is examined using the photoelasticity technique with a 40 mm embedment length. Whereas the pullout mechanism between the fibers with the cementitious matrix is examined for a single string of fiber using a pullout test with varied embedment lengths of 10, 20, 30, 40, 50, 60, 70, and 80 mm. From the study, the minimum and maximum bond stress between the fiber and epoxy interface is 3.23 MPa and 11.59 MPa respectively. Whereas between the fiber and cementitious interface, the minimum and maximum bond stress is 1.02 MPa and 2.15 MPa respectively. The experimental results are validated by the Weibull modulus approach which shows less variability. Thus, the results of the pullout test in composite matrix recommend the usage of waste badminton strings in fiber-reinforced concrete applications. [ABSTRACT FROM AUTHOR]

It has been realized throughout the years that an ideal combination of high toughness, hardness and strength is required in many engineering applications that need load-bearing capabilities. Ceramics and related materials have significant constraints for structural and particular non-structural applications due to their low toughness and limited strength while having substantially superior hardness than typical metallic materials. For example, hydroxyapatite (HAp) has gained attention for applications in orthopaedic implants, dental materials, drug delivery, etc. Researchers have continued to strive to produce HAp materials with reliable properties within the acceptable Weibull modulus (m) for load bearing. The Weibull analysis (WA) is a statistical analysis adopted widely in reliability applications to detect failure periods. Researchers have confirmed it to be an effective technique to get results on the reliability of materials at a moderately low rate with assured reliability of the material or component. This review summarizes the WA and the steps in the Weibull method for its reliability analysis to predict the failure rate of ceramics like HAp and other related materials. Also, the applications of WA for these materials were reviewed. From the review, it was discovered that Weibull distribution is proven to confer to the feeblest-link concept. For brittle materials, it was revealed that the Weibull Modulus ranges from 2 to 40, and environment, production processes, and comparative factors are well-thought-out contributing factors for reliability. In addition, the confidence interval can be up to 95 %. The frequently used technique for reliability valuation is to syndicate the Weibull statistics. Also, a very narrow distribution is desirable to offer the expected likelihood. Furthermore, when paired with trials, Monte Carlo simulations prove to be a very helpful tool for forecasting the dependability of different estimate techniques and their optimization. Finally, if the equivalent m is anticipated to be high, it signifies that the material has a high degree of homogeneity of properties and high reliability. WA can find application in predicting the dependability and lifetime of materials, making it widely utilized in engineering and other disciplines. It is especially useful for analysing data in which the likelihood of failure per unit of time varies over time.

Mechanical characterization of ceramics is challenging, as the statistical nature of their strength requires numerous specimens to extract reliable distribution parameters. Here, we first propose a high-throughput testing procedure that allows extraction of statistical information on the strength of ceramic materials. We process large numbers of bending specimens from low volumes of material via Direct Ink Writing (DIW), and rapidly characterize them to extract Weibull parameters for bending strength. After investigating five ceramics and downselecting two formulations, we develop a multi-scale procedure to explore the impact of printing-induced defects on the strength distribution of DIW-processed ceramics. Finally, we demonstrate that a judicious choice of the printing strategy produces porous architected structures which can significantly exceed the strength of fully dense DIW-produced monolithic materials. While the results are presented on DIW-processed alumina-based ceramics, the approach is versatile and can provide rapid statistical data on the strength of many ceramic materials.

Purpose: The purpose of this in vitro study was to compare the flexural strength and Weibull characteristics of 3 different resin‐ceramic materials with a zirconia‐reinforced lithium silicate material after thermal‐cycling. Material and methods: Four different computer‐aided design and computer‐aided manufacturing restorative materials (Vita Enamic, Lava Ultimate, Crystal Ultra, and Vita Suprinity) were tested. A total of 40 Ø12×1.2‐mm disks were prepared and divided into 4 groups (n = 10). Their flexural strength was evaluated after 5000 thermal‐cycles with a 4‐point biaxial flexure test using a universal testing machine. The Weibull modulus and probability of failure were also determined from the biaxial flexural strength data. Data were analyzed with one‐way ANOVA and the Tukey pairwise comparison test (α = 0.05). Results: Significant differences were found among the materials in terms of biaxial flexural strength (p < 0.05). Vita Suprinity had the highest mean ±standard deviation flexural strength (289.1 ± 15.1 MPa), and Vita Enamic had the lowest (100.0 ± 3.2 MPa). The highest Weibull modulus was calculated for Crystal Ultra, followed by Vita Enamic, Lava Ultimate, and Vita Suprinity. Conclusion: Vita Suprinity had the highest flexural strength when compared with the other materials tested. Crystal Ultra had the highest flexural strength among the resin‐ceramic materials. The highest Weibull modulus was calculated for Crystal Ultra and the lowest for Vita Suprinity. [ABSTRACT FROM AUTHOR]

The mechanical and electrical properties relation are very important, especially for brittle material. Nano Alumina-unsaturated polyester (PS/Al2O3) composites were prepared by casting PS with different percentages (1, 2, 3, and 4 wt%) of Nano alumina. Electrical breakdowns caused cracks to form around the breakdown point, and the length and quantity of cracks increased with dispersed powder added increases. The research involved determining Weibull modulus from an electrical strength test, and mechanical strength by piston-on-three-ball test. The results showed that Weibull modulus and dielectric breakdown increase during the rate of rising voltage (RRV) increases, especially 5 kV/s. the maximum Weibull modulus measured by the electrical breakdown was at a high RRV is 34.58 (PS/Al2O3). High RRV leads to electromechanical breakdown and electrothermal strength at low RRV. While the Weibull modulus by the piston-on-three-balls test is lower than the Weibull modulus calculated by electrical strength. Therefore, this mechanical test is more accurate in identifying defects that fail due to an increase in the affected area of the applied stress. Scanning electron microscope (SEM) images showing the homogeneous distribution of the powders within the polymeric matrix. Some pores were present in the structure of the composite despite the measures taken to increase the dispersion using ultrasound waves. Those pores caused fluctuating results in all electrical and mechanical tests.

Due to rampant building collapse in Nigeria, several works have been conducted on rebars in Nigeria without recourse to statistical analysis of the tensile and characterization. In this paper, an experimental investigation was performed to understand the mechanical properties and characteristics of reinforcement bars (rebars) produced from scraps in Nigeria. The tensile strength of twenty-two samples for each type of manufactured rebar was subjected to probability analysis using a two-parameter Weibull probability distribution model. The characterization of the rebars was performed using optical emission spectroscopy (OES), x-ray diffraction (XRD) and scanning electron microscopy (SEM). Hardness and impact strength of the rebars were determined using Brinell hardness test and Charpy test, respectively. The result revealed that the carbon content of all the rebars was more than the required amount specified by international standards for a classical rebar material. The presence of flaws in the rebars has significant influence on the mechanical properties of the rebars. The two-parameter Weibull probability distribution shows that the Weibull parameters such as the Weibull modulus and the scale parameter values were very low compared to the literature. [ABSTRACT FROM AUTHOR]

In this paper, how to determine the Weibull modulus of a fracture strength distribution is discussed with its physical implications for quasi-brittle materials. Based on the Markov chain assumption, it is shown that the lifetime (i.e., the time taken for formation of a critical defect) in a quasi-brittle material can be described by a gamma probabilistic distribution function. Prior to macroscopic failure, the effective number of energy barriers to be overcome is determined by the slope of the energy barrier spectrum, which is equivalent to the Weibull modulus. Based on a fracture mechanics model, the fracture energy barrier spectral slope and Weibull modulus can be calculated theoretically. Furthermore, such a model can be extended to take into account the crack interactions and defect-induced degradation. The predicted Weibull modulus is good agreement with that derived from available experimental results. [ABSTRACT FROM AUTHOR]

The main goal of this study is to assess the mechanical, physical and morphological properties of bundle fibers extracted from curaua leaves and pullout testing in cementitious matrix. The mechanical properties of the fibers were analyzed in mechanical testing of four fiber lengths (10, 20, 30 and 40 mm) to observe the influence of the length of the variable’s tensile strength, Young’s modulus and Weibull modulus. Pullout testing was measured frictional and maximal force. Fibers physical properties were assessed by means of the multipycnometer method. Morphological analyses were conducted through optical and scanning electron microscopes. The results showed that the fiber length does not interfere with the tensile strength (507–638 MPa) and Weilbull modulus (8–12). However, it influences the Young’s modulus (19–39 GPa). Curaua bundles present a higher resistance to rupture and Young’s modulus than other plant fibers species and it seems to be related to the distribution of faults along the beam. The fibers morphological characterization showed a rough and irregular surface with some impurities which are associated with the surface of the fibrous bundle and low adherence (0,26–0,47 N) with cementitious matrix in pullout testing.

Direct metal laser sintered Ti–6Al–4V samples, with intentionally induced defects generated by varying the process parameters, were analyzed using microtensile testing techniques. Samples with defects exhibited statistically-significant larger microtensile than macrotensile ultimate strengths. Weibull microtensile moduli are smaller than macrotensile moduli indicating greater variability. Comparing the microtensile results to macrotensile properties reveals how changing these process parameters affects the range of mechanical behaviors potentially present in additively-manufactured parts due to the varying microstructures in the material.

During binderjetting of bioceramics, many commercial 3D printers dispense binder in a default 'core-shell' manner. Using such a conventional approach, more binder is dispensed at the periphery (shell) and less binder at the 'core' of the structure. The inhomogeneous binding of the powder particles from the shell to the core significantly impacts the microstructure and biomechanical properties. To address this, we hypothesised 'segmentation' of a 3D printable design file by slicing and discretising with an array of thin solid "segments", separated with an infinitesimal gap in a periodic manner. In this novel approach, the printing software commands the printhead to print each of the "segments" individually. The inter-segment and intra-segment binder "bleeding" among the segments results in a printed part with a homogeneously bound cross-section, without any "core-shell" effect. This hypothesis was experimentally validated by better microstructure, improved density, and enhanced mechanical strength properties in binderjet printed 3 mol% yttria stabilised ZrO 2. [ABSTRACT FROM AUTHOR]

This work addresses the feasibility of using waste badminton string fiber in cement and polymer matrices. A badminton racquet, once used, is torn and needs replacement with new strings. These torn strings, once cut from the badminton racquet system, become waste, and these fibers cannot be recycled and remain debris. Hence, this study examines the microstructural and mechanical properties of new fibers and old torn fibers comparatively. Scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and energy dispersive spectroscopy are used to study the microstructural properties of the fiber. Direct tensile stress is applied to new and old fibers in the universal testing machine varying by one, three, and five strands of the fibers and varying the gauge length to 60, 80, and 100 mm, and the respective energy absorption is calculated. From investigation with a varying number of strands, similar results were observed in both old and new fibers from energy absorption and residual force ratio. From investigation with varying gauge length, the tensile stress of new fibers varies between 648.53 and 749.03 MPa, and that of old fibers is 537.40–625.55 MPa. Young's modulus for new and old fibers is 4870.00 and 4843.50 MPa, respectively. The Weibull statistical approach is used to test the variability of test results. The Weibull modulus varies between 5.27 and 9.17, which shows lower variability. Thus, the tensile stress results obtained for the discarded badminton fibers pave way for incorporating these fibers in cement and polymer matrices to improve the matrix properties. [ABSTRACT FROM AUTHOR]

This study examines methods for simplifying estimation of the Weibull modulus. This parameter is an important instrument in understanding the statistical behavior of the strength of materials, especially those of brittle solids. It is shown that a modification of Robinson’s approximate expression can provide good estimates of Weibull modulus values (m) in terms of average strength () and standard deviation (S): m = 1.10 /S. This modified Robinson relation is verified on the basis of 267 Weibull analyses accompanied by and S measurements. Estimated m values matched normally obtained m values on average within 1%, and each pair of m values was within ± 20%, except for 11 cases. Applications are discussed, indicating that the above relation can offer a quantitative tool based on the Weibull theory to engineering practice. This survey suggests a rule of thumb: ductile metal alloys have Weibull moduli of 10 to 200.

The Weibull distribution has been widely used to model strength properties of brittle materials. Estimation of confidence intervals for Weibull shape parameter has been an important concern, since small sample sizes in materials science experiments bring about large intervals. Many methods have been proposed in the literature for constructing shorter intervals; the methods of maximum likelihood, least square, and Menon are among the most extensively studied methods. However, they all use an equal-tails approach. The pivotal quantities used for constructing confidence intervals have right-skewed and unimodal distributions, thus, they clearly do not produce the shortest intervals for a given confidence level in equal tail form. This study constructs the shortest confidence intervals for the three aforementioned methods and compares their performances by their equal-tails counterparts. To this end, a comprehensive simulation study has been conducted for the shape parameter values between 1 to 80 and the sample sizes between 3 to 20. The comparison criterion is chosen as the expected interval length. The results show that the shortest confidence intervals in each of three methods have yielded considerably narrower intervals. Further, the unknown parameter values are more centered in these intervals. [ABSTRACT FROM AUTHOR]

In this study, the effects of heat-treatment temperature and hot-end coating (HEC) by spray coating on the mechanical properties and reliability of lightweight glass bottles were investigated. When the chemical strengthening occurred at Tg, the hardness and impact strength increased by 163% and 198%, respectively. All specimens exhibited improved mechanical properties with chemical strengthening, regardless of the HEC. The strengthening effect was relatively large in the absence of HEC. However, the distribution of the impact strength was smaller when HEC was applied. Compared to non-HEC bottles, HEC glass bottles had higher Weibull modulus values after chemical strengthening, which increased their reliability. Therefore, it is possible to chemically strengthen a lightweight glass bottle by spray-coating. Chemically strengthened lightweight glass bottles with excellent mechanical properties and high reliability can be produced when both HEC and chemical strengthening are applied. [ABSTRACT FROM AUTHOR]

The main goal of this study is to assess the mechanical, physical and morphological properties of bundle fibers extracted from curaua leaves and pullout testing in cementitious matrix. The mechanical properties of the fibers were analyzed in mechanical testing of four fiber lengths (10, 20, 30 and 40 mm) to observe the influence of the length of the variable's tensile strength, Young's modulus and Weibull modulus. Pullout testing was measured frictional and maximal force. Fibers physical properties were assessed by means of the multipycnometer method. Morphological analyses were conducted through optical and scanning electron microscopes. The results showed that the fiber length does not interfere with the tensile strength (507–638 MPa) and Weilbull modulus (8–12). However, it influences the Young's modulus (19–39 GPa). Curaua bundles present a higher resistance to rupture and Young's modulus than other plant fibers species and it seems to be related to the distribution of faults along the beam. The fibers morphological characterization showed a rough and irregular surface with some impurities which are associated with the surface of the fibrous bundle and low adherence (0,26–0,47 N) with cementitious matrix in pullout testing. [ABSTRACT FROM AUTHOR]

This study aimed to determine the effect of the testing method configuration on the bi-axial flexural strength (BFS) of three resin-based dental composites (RDCs). A total of 180 disc-shaped samples (12 mm diameter x 1 mm thickness) for each RDC were fabricated using split back nylon mould. The BFS was determined for specimens made in three commercial RDCs; microhybrid (MH), nanofilled paste (NFP) and nanofilled flowable (NFF) using the ring-on-ring (RoR; n = 90 for each RDC specimens) and ball-on-ring (BoR; n = 90 for each RDC specimens) configurations at a cross-head speed of 1 mm/min. RDC specimens of MH and NFP tested in the BoR configuration showed higher mean BFS values compared to those tested in the RoR configuration. (p < 0.001). The effect of test configuration on BFS values was insignificant for the specimens belonging to the NFF group (p = 0.207). Moreover, the Weibull modulus of NFF in the RoR configuration was statistically lower compared to those for NFF in the BoR configuration as the 95% confidence interval of Weibull modulus did not overlap. The specimen support and testing configuration significantly impacted the BFS value of the RDCs. The Weibull statistics appeared to be inappropriate for all kinds of RDCs. [ABSTRACT FROM AUTHOR]

Semi-closed cell macroporous alumina foams with relative densities ranging from 0.26 to 0.35 have been produced by the well-established replication method based on the coating of a polyurethane (PU) template foam by a ceramic slurry, followed by burnout of the PU template, and sintering of the ceramic skeleton. Collapse of the three-dimensional structure upon the volatilisation of the PU sponge can only be prevented using appropriate binders. Scarce data are available on the slurry formulations of commercial alumina foams. The aim of this study was to investigate the influence of silicate-type binders, namely kaolin and bentonite additives, on the crushing strength of alumina foams. The highest crushing strength of around 10 MPa was observed at a porosity of 66 ± 2%. The open-cell model is inadequate to fit the crushing strength data of such semi-closed cell type structures. Both microscopic and macroscopic flaws resulting from the foam processing method contribute to the wide scatter of the strength, thereby explaining the Weibull modulus ranging from 4 to 7. Both flaw populations require further improvement to maximise the crushing strength of these foams with high potential for the design of structured catalyst carriers and molten aluminium filters. [ABSTRACT FROM AUTHOR]

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Ethiopia has a large coverage of bamboo plants that are used for furniture making and house building. So far, researchers have not studied the strength of Ethiopian bamboo fibers, which are utilized for composite applications. The current study measured the strength of bamboo fibers based on various testing lengths and calculated the predictive tensile strength using a modified Weibull distribution. Moreover, the quality of the extraction machine is evaluated based on shape and sensitivity parameters. This research paper incorporates the coefficient of variation of the fiber diameters, considering the defects distribution through the length for measuring the predictive strength of the fibers. The fiber diameters were calculated using the area weight methods, which had its density measured using a Pycnometer. It has been examined that as the testing gauge length and coefficient variation of fiber diameter simultaneously increased, the tensile strength of the bamboo fibers decreased. The shape parameter, sensitivity parameter, and characteristic strength of Injibara bamboo (Y. alpina) are 6.02–7.83, 0.63, and 459–642 MPa, whereas Kombolcha bamboo (B. oldhamii) are 5.87–10.21, 0.33, and 408–638 MPa, as well as Mekaneselam bamboo (Y. alpina) are 5.86–9.63, 0.33 and 488–597 MPa, respectively. [ABSTRACT FROM AUTHOR]

Enset bundle fibers were divided lengthwise into four sections from bottom to top and the sections' physio-mechanical parameters were studied and compared. The four equal fiber sections from the bottom were 0–375 mm (EV-I), 375–750 mm (EV-II), 750 mm–1125 mm (EV-III), and 1125–1500 mm (EV-IV). The mass distribution, cross-sectional area, linear density, and diameter all decreased along the fiber sections from bottom to top. The CIE Lab-color values of each fiber section were also examined, and the L* value for EV-II fiber section was higher. In terms of mechanical properties, the Enset bundle fiber's tensile strength and work of rupture were analyzed, and both increased by 25% from the lower fiber section to the second fiber section (EV-1 to EV-II) along the length before decreasing significantly at the top sections. The investigation indicated that a higher Weibull modulus and tensile strength characteristics for EV-II were recorded while a low Weibull modulus and low strength characteristics of the Enset bundle fiber section EV-IV were observed. The investigation of Weibull distribution variability in the EV-IV fiber location was also confirmed using one-way ANOVA. Overall, the present study investigates the impact of fiber position along the plant stem on the mechanical and physical properties of Enset bundle fibers which can be used as an input for the optimization of unidirectional composites. [ABSTRACT FROM AUTHOR]

To compare the mechanical properties of different layers of multi-layered zirconia materials. 720 cylindric test plates were fabricated from four defined layers of three multi-layered zirconia ceramics (IPS e.max ZirCAD Prime, Optimill Multilayer 3D; Ceramill zolid fx multilayer) and divided into two equal groups. One group underwent thermal cycling (5–55 °C, 10 000 cycles; "TC") and one did not ("no TC"), before density, flexural strength, Weibull modulus, and Vickers hardness were evaluated. EDX analysis was conducted using an additional cylinder of each material. Data were analyzed using Kruskal–Wallis and Mann–Whitney U tests. Statistical analysis was performed with Bonferroni correction (α < 0.001). After aging, ZirCAD layer 4 showed the overall highest density (6.04 ± 0.02 g/cm3), which was significantly higher than density of layer 4 of Optimill (6.02 ± 0.06 g/cm3) and Ceramill (5.80 ± 1.08 g/cm3) (both p < 0.001). Flexural strength of ZirCAD and Optimill increased consecutively after thermal aging. ZirCAD layer 4 had the overall highest flexural strength before and after artificial aging. After thermal cycling, the Weibull modulus ranged between 4.32 (ZirCAD layer 1) and 13.58 (Ceramill layer 4). ZirCAD had the overall highest Vickers hardness: in layer 1 (1579.18 ± 47.14 HV) before aging, and in layer 2 (1607.1 ± 149.71 HV) after aging. Flexural strength and Vickers hardness differed significantly between the four ZirCAD layers (p < 0.001). Thermal ageing had no significant impact on mechanical properties (p > 0.001). Mechanical properties were affected by plate position within the blank. When nesting a restoration within a multi-layered zirconia blank, the mechanical properties required should be considered. [ABSTRACT FROM AUTHOR]

The work idea is finding out how the homogeneity of dielectric strength property in lithium metasilicate glass-ceramic with addition weight percentage increasing of CuO. It prepared four specimens, one without CuO addition lithium metasilicate glass-ceramic LSGC and consists of Li2O-SiO2 binary system glass batch with weight percentages 45 wt% Li2O and 55 wt% SiO2. It added to the binary system CuO with different weight percentages to prepare the rest three specimens in front of the Li2O weight percentage decreasing as 1 wt% LC1S, 2 wt% LC2S, and 3 wt% LC3S. The glass batches for four specimens were mixed and used melting-quenching method at temperature of 1195OC for soaking time 2 hrs. It used platinum crucible (90 Pt-10 Rh) and immediately cooled in the cold water of temperature at 3OC. This process was repeated twice for all specimens and the produced frit was milled by agate mortar. Addition of P2O5 and TiO2 as nucleating agents with weight percentage 3 wt% P2O5 and 1 wt% TiO2 and prepared compact discs with dimensions 18 diameter × 2.58 thickness mm by the used biaxial hydraulic press with 5 ton for 30 s under pressure. The heat treatment was done for all glass batch compact discs of temperature at 950OC for 6 hrs as soaking time and breakdown voltage test was done executed 10 different spots in each specimen and Weibull modulus was used to know the homogeneity of dielectric strength property and coincided with Field Emission Scanning Electron Microscopes (FE-SEM) images. It got a good match between Weibull modulus results and FESEM images which indicating that Weibull modulus is the active tool that can be used for knowing the homogeneity of any property. The high average dielectric strength is 9.116 kV/mm for LC1S while the lower average dielectric strength is 7.101 kV/mm for LSGC and this back to more homogeneity and fewer defects in LC1S than LSGC.

Abstract The effect of pyrolytic carbon (PyC) thickness on the tensile property of mini T800 carbon fiber reinforced SiC matrix composites (C/SiC) was studied. PyC interphase was prepared by chemical vapor infiltration (CVI) process using C3H6–Ar as gas source, the PyC thickness was adjusted from 0 to 400 nm, and then the SiC matrix was prepared by CVI process using methyltrichlorosilane (MTS)–H2–Ar as precursor and gas source. The results showed that the tensile strength of mini T800-C/SiC increased first and then decreased with the increase of the PyC thickness. When the thickness of PyC was 100 nm, the average strength reached the maximum value of 393 ± 70 MPa. The Weibull modulus increased from 2.0 to 8.06 with the increase of PyC thickness, and the larger the Weibull modulus, the smaller the dispersion, which indicated that the regulation of PyC thickness was conducive to improve tensile properties.

This work addresses the feasibility of using waste badminton string fiber in cement and polymer matrices. A badminton racquet, once used, is torn and needs replacement with new strings. These torn strings, once cut from the badminton racquet system, become waste, and these fibers cannot be recycled and remain debris. Hence, this study examines the microstructural and mechanical properties of new fibers and old torn fibers comparatively. Scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and energy dispersive spectroscopy are used to study the microstructural properties of the fiber. Direct tensile stress is applied to new and old fibers in the universal testing machine varying by one, three, and five strands of the fibers and varying the gauge length to 60, 80, and 100 mm, and the respective energy absorption is calculated. From investigation with a varying number of strands, similar results were observed in both old and new fibers from energy absorption and residual force ratio. From investigation with varying gauge length, the tensile stress of new fibers varies between 648.53 and 749.03 MPa, and that of old fibers is 537.40–625.55 MPa. Young’s modulus for new and old fibers is 4870.00 and 4843.50 MPa, respectively. The Weibull statistical approach is used to test the variability of test results. The Weibull modulus varies between 5.27 and 9.17, which shows lower variability. Thus, the tensile stress results obtained for the discarded badminton fibers pave way for incorporating these fibers in cement and polymer matrices to improve the matrix properties.

The effect of carbon nanotubes (CNTs) on the tensile properties of polyacrylonitrile (PAN)-based carbon fiber epoxy impregnated bundle composites was investigated. To grow CNTs on the carbon fibers, the following catalysts were selected: Ferrocene ([Fe(C5H5)2]) catalyst applied to the bundles using chemical vapor deposition (CVD), and iron (III) nitrate nonahydrate ([Fe(NO3)3•9H2O]) catalyst applied by dipping the bundles in ethanol solutions of different concentrations ranging from 0.01 to 0.5 M. For bundle composites with Fe(C5H5)2-catalyzed CNTs, the Weibull modulus was 29% higher than the as-received state, although the tensile strength is almost unchanged. The Weibull modulus is 9–39% higher than the as-received state for Fe(NO3)3•9H2O catalyst solutions in the range 0.01–0.3 M, while it decreases by 22–32% for 0.4–0.5 M solutions. The tensile strength is lower in both cases; 4–7% lower for 0.01–0.3 M solutions and 14–17% lower for 0.4–0.5 M solutions. Fe(NO3)3•9H2O catalysts 0.1 M solutions gives the best combination of tensile strength and Weibull modulus improvement. The results also show that for each type of CNT-grafted and as-received PAN-based carbon fibers, an almost linear relation between the Weibull modulus and average tensile strength on the log-log scale is observed. This relation indicates that Fe(C5H5)2 catalyst-grafting of CNTs gives better tensile strength and Weibull modulus results. [ABSTRACT FROM AUTHOR]

It has been realized throughout the years that an ideal combination of high toughness, hardness and strength is required in many engineering applications that need load-bearing capabilities. Ceramics and related materials have significant constraints for structural and particular non-structural applications due to their low toughness and limited strength while having substantially superior hardness than typical metallic materials. For example, hydroxyapatite (HAp) has gained attention for applications in orthopaedic implants, dental materials, drug delivery, etc. Researchers have continued to strive to produce HAp materials with reliable properties within the acceptable Weibull modulus ( m) for load bearing. The Weibull analysis (WA) is a statistical analysis adopted widely in reliability applications to detect failure periods. Researchers have confirmed it to be an effective technique to get results on the reliability of materials at a moderately low rate with assured reliability of the material or component. This review summarizes the WA and the steps in the Weibull method for its reliability analysis to predict the failure rate of ceramics like HAp and other related materials. Also, the applications of WA for these materials were reviewed. From the review, it was discovered that Weibull distribution is proven to confer to the feeblest-link concept. For brittle materials, it was revealed that the Weibull Modulus ranges from 2 to 40, and environment, production processes, and comparative factors are well-thought-out contributing factors for reliability. In addition, the confidence interval can be up to 95 %. The frequently used technique for reliability valuation is to syndicate the Weibull statistics. Also, a very narrow distribution is desirable to offer the expected likelihood. Furthermore, when paired with trials, Monte Carlo simulations prove to be a very helpful tool for forecasting the dependability of different estimate techniques and their optimization. Finally, if the equivalent m is anticipated to be high, it signifies that the material has a high degree of homogeneity of properties and high reliability. WA can find application in predicting the dependability and lifetime of materials, making it widely utilized in engineering and other disciplines. It is especially useful for analysing data in which the likelihood of failure per unit of time varies over time., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Semi-closed cell macroporous alumina foams with relative densities ranging from 0.26 to 0.35 have been produced by the well-established replication method based on the coating of a polyurethane (PU) template foam by a ceramic slurry, followed by burnout of the PU template, and sintering of the ceramic skeleton. Collapse of the three-dimensional structure upon the volatilisation of the PU sponge can only be prevented using appropriate binders. Scarce data are available on the slurry formulations of commercial alumina foams. The aim of this study was to investigate the influence of silicate-type binders, namely kaolin and bentonite additives, on the crushing strength of alumina foams. The highest crushing strength of around 10 MPa was observed at a porosity of 66 ± 2%. The open-cell model is inadequate to fit the crushing strength data of such semi-closed cell type structures. Both microscopic and macroscopic flaws resulting from the foam processing method contribute to the wide scatter of the strength, thereby explaining the Weibull modulus ranging from 4 to 7. Both flaw populations require further improvement to maximise the crushing strength of these foams with high potential for the design of structured catalyst carriers and molten aluminium filters.

The influence of ultrasonic degassing process on fluidity and hardness of secondary Al7Si0.3Mg alloy castings was studied by Weibull analysis. This work makes a contribution about fluidity and hardness distribution of secondary aluminum alloys with ultrasonic degassing phenomena using a two-parameter form of Weibull analysis. Results show that both hardness and fluidity of alloy are improved after the ultrasonic degassing process. Average efficiency of ultrasonic degassing on fluidity measurements is 31.71%, whereas on hardness values is 8.48%. The Brinell hardness of 45.7 and fluidity of 19.5 of Weibull modulus were achieved as the most reliable and reproducible after 45 s ultrasonic degassing process against 15 s and 30 s ultrasonic degassing processes. The value of 70.08 HB is obtained from ultrosonic degassing, which is equivalent to sand casting of primary Al7Si0.3Mg aluminum alloy, and the highest value of 56.4 cm for 45 s after ultrasonic degassing of fluidity was measured.

Enset bundle fibers were divided lengthwise into four sections from bottom to top and the sections’ physio-mechanical parameters were studied and compared. The four equal fiber sections from the bottom were 0–375 mm (EV-I), 375–750 mm (EV-II), 750 mm–1125 mm (EV-III), and 1125–1500 mm (EV-IV). The mass distribution, cross-sectional area, linear density, and diameter all decreased along the fiber sections from bottom to top. The CIE Lab-color values of each fiber section were also examined, and the L* value for EV-II fiber section was higher. In terms of mechanical properties, the Enset bundle fiber’s tensile strength and work of rupture were analyzed, and both increased by 25% from the lower fiber section to the second fiber section (EV-1 to EV-II) along the length before decreasing significantly at the top sections. The investigation indicated that a higher Weibull modulus and tensile strength characteristics for EV-II were recorded while a low Weibull modulus and low strength characteristics of the Enset bundle fiber section EV-IV were observed. The investigation of Weibull distribution variability in the EV-IV fiber location was also confirmed using one-way ANOVA. Overall, the present study investigates the impact of fiber position along the plant stem on the mechanical and physical properties of Enset bundle fibers which can be used as an input for the optimization of unidirectional composites.

Ethiopia has a large coverage of bamboo plants that are used for furniture making and house building. So far, researchers have not studied the strength of Ethiopian bamboo fibers, which are utilized for composite applications. The current study measured the strength of bamboo fibers based on various testing lengths and calculated the predictive tensile strength using a modified Weibull distribution. Moreover, the quality of the extraction machine is evaluated based on shape and sensitivity parameters. This research paper incorporates the coefficient of variation of the fiber diameters, considering the defects distribution through the length for measuring the predictive strength of the fibers. The fiber diameters were calculated using the area weight methods, which had its density measured using a Pycnometer. It has been examined that as the testing gauge length and coefficient variation of fiber diameter simultaneously increased, the tensile strength of the bamboo fibers decreased. The shape parameter, sensitivity parameter, and characteristic strength of Injibara bamboo (Y. alpina) are 6.02–7.83, 0.63, and 459–642 MPa, whereas Kombolcha bamboo (B. oldhamii) are 5.87–10.21, 0.33, and 408–638 MPa, as well as Mekaneselam bamboo (Y. alpina) are 5.86–9.63, 0.33 and 488–597 MPa, respectively.

Estimating the confidence interval of the Weibull modulus is an important problem in the fracture strength modeling of ceramic and composite materials. It is particularly important in cases where the sample size is small due to high experimental costs. For this purpose, several classical methods, including the popular maximum likelihood method, and Bayesian methods have been developed in the literature. However, studies on Bayesian inference have remained very limited in the materials science literature. Recently a Bayesian Weibull model has been proposed for estimating confidence lower bounds for Weibull percentiles using the prior knowledge that the failure rates are increasing. This prior argument requires the Weibull modulus to be more than 1 due to wear-out failure. In this study, under the same prior information, two Bayesian Weibull models, one using the same prior argument and the other a relaxed version of it, have been developed for confidence interval estimation of the Weibull modulus. Their estimation performances have been compared against the maximum likelihood method with Monte Carlo simulations. The results show that the Bayesian Weibull models significantly outperform the maximum likelihood method for almost all Weibull modulus and sample size values. [ABSTRACT FROM AUTHOR]

Purpose: This study evaluated the flexural strength of bulk-fills after immersion in food-simulating solvents.Methods: Four overlapping segments along both sides of bar-shaped specimens (25 × 2 × 2 mm) made from bulk-fill composite were irradiated with an Elipar LED light-curing (1,200 mW/cm2 for 20 s) device. The specimens were then divided into four groups (n = 20), according to storage media-namely, distilled water, 99% ethanol, heptane, and methyl ethyl ketone-at 37oC for 4 weeks. Flexural testing was done with a universal testing machine at a crosshead speed of 1 mm/min.Results: Data were analyzed with the two-way and one-way ANOVA and post-hoc Tukey (HSD) tests (P < 0.05), along with the Weibull statistic. Flexural properties significantly differed in relation to the bulk-fill and solvent used. The flexural properties of bulk-fills decreased in solvents. SonicFill in distilled water had the highest values for flexural properties (σf = 165.77 MPa; Ef = 10.3 GPa), followed by the values for SonicFill in ethanol and those for X-tra base and everX Posterior in water. Venus Bulk Fill in methyl ethyl ketone yielded the lowest values (σf = 74.11 MPa; Ef = 3.06 GPa).Conclusion: The flexural properties of bulk-fills are affected by the food-simulating solvent used and by the filler content, type, and resin component. [ABSTRACT FROM AUTHOR]

3D binderjet printing of bioceramics remained a major challenge, and powder specific-binder development and processing strategies still follow certain ‘black box’ approaches. In this study, for the first time, we report the efficacy of an acrylic based proprietary binder system to 3D print zirconia based bioceramics. Machine limited ‘core-shell’ mode of binder deposition resulted in heterogeneous distribution in particle arrangement from ‘shell’ to ‘core’, with higher binder saturation at the ‘shell’ region and less saturation at the ‘core’. A series of post-processing strategies like ‘presintering – salt infiltration – phase conversion – final sintering’, post-printing binder infiltration etc. were adapted to develop 3YSZ alone or together with ZrSiO4 or Al2O3, although with limited success. Despite poor strength properties (compressive/tensile/flexural), the acceptable strength reliability with modest Weibull modulus (m ​≈ ​5–9) was obtained in post-processed ceramics. While explaining the microstructure-property correlations, the contributions of different powder modification strategies and novel processing steps (‘dual powder deposition’ for non-macroporous powder bed) are discussed in particular reference to the porous architecture formed in 2D space or 3D volume, as investigated using SEM or micro-computed tomography.

Entrapped double oxide film defects are known to be the most detrimental defects during the casting of aluminium alloys. In addition, hydrogen dissolved in the aluminium melt was suggested to pass into the defects to expand them and cause hydrogen porosity. In this work, the effect of two important casting parameters (the filtration and hydrogen content) on the properties of Al–7 Si–0.3 Mg alloy castings was studied using a full factorial design of experiments approach. Casting properties such as the Weibull modulus and position parameter of the elongation and the tensile strength were considered as response parameters. The results suggested that adopting 10 PPI filters in the gating system resulted in a considerable boost of the Weibull moduli of the tensile strength and elongation due to the enhanced mould filling conditions that minimised the possibility of oxide film entrainment. In addition, the results showed that reducing the hydrogen content in the castings samples from 0.257 to 0.132 cm3/100 g Al was associated with a noticeable decrease in the size of bifilm defects with a corresponding improvement in the mechanical properties. Such significant effect of the process parameters studied on the casting properties suggests that the more careful and quiescent mould filling practice and the lower the hydrogen level of the casting, the higher the quality and reliability of the castings produced.

PEEK (poly ether ether ketone) materials printed using FFF 3D printing have been actively studied on applying electronic devices in satellites owing to their excellent light weight and thermal resistance. However, the PEEK FFF process generated cavities inside due to large shrinkage has degraded both mechanical integrity and printing reliability. Here, we have investigated the correlations between nozzle temperatures and PEEK printing behaviors such as the reliability of printed line width and surface roughness. As the temperature increased from 360 to 380 °C, the width of the printed line showed a tendency to decrease. However, the width of PEEK printed lines re-increased from 350 to 426 μm at the nozzle temperatures between 380 and 400 °C, associated with solid to liquid-like phase transition and printed out distorted and disconnected lines. The surface roughness of PEEK objects increased from 49 to 55 μm as the nozzle temperature increased from 380 to 400 °C, where PEEK is melted down and quickly solidified based on more energy and additional heating time at higher printing temperatures at 400 °C. Based on these printing trends, a reliability analysis of the printed line was performed. The printed line formed the most uniform width at 380 °C and had a highest Weibull coefficient of 28.6 using the reliability analysis technique called Weibull modulus.

Abstract Extrusion-based fused deposition modeling (FDM) introduces inter-bead pores into dense materials, which results in part-to-part mechanical property variations, i.e., low mechanical reliability. In addition, the internal structure of FDMed materials can be made porous intentionally to tailor mechanical properties, introduce functionality, reduce material consumption, or decrease production time. Despite these potential benefits, the effects of porosity on the mechanical reliability of FDMed composites are still unclear. Accordingly, we investigated the stochastic fracture of 241 FDMed short-carbon-fiber-reinforced-ABS with porosity ranging from 13 to 53 vol.% under tensile load. Weibull analysis was performed to quantify the variations in mechanical properties. We observed an increase in Weibull modulus of fracture/tensile strength for porosity higher than ~40 vol.% and a decrease in Weibull modulus of fracture strain for an increase in porosity from 25 to 53 vol.%. Micromechanics-based 2D simulations indicated that the mechanical reliability of FDMed composites depends on variations in bead strength and elastic modulus of beads. The change in raster orientation from 45°/−45° to 0° more than doubled the Weibull modulus. We identified five different types of pores via high-resolution X-ray computed tomography. A 22% and 48% decrease in carbon fiber length due to extrusion was revealed for two different regions of the filament.

In this work, a cast alloy of Al–Zn–Mg was developed from aluminium from recycled beverage cans and zinc scraps from battery and the influence of age-hardening heat treatment of the alloy on mechanical properties and reliability analysis on the tensile strength was investigated. The cast Al–Zn–Mg alloy was subjected to age-hardening heat treatment at different times. The aluminium, cast alloy and age-hardened alloy were characterized using XRF, XRD and TEM. The mechanical properties were investigated using a hardness test, impact strength test and percentage elongation. Also, the tensile strength data were subjected to a reliability analysis using Weibull probability distribution. From the results, it shows that 24 h ageing time is enough to have optimum mechanical properties due to an increase in size of the stable MgZn2s phase particles. The reliability analysis shows that the alloy aged at 24 h has tensile strength value (229.72 MPa) in the range reported for Al–Zn–Mg alloy's temper designations. [ABSTRACT FROM AUTHOR]

Digital light processing (DLP) is a relatively mature technology of ceramic additive manufacturing and is promising for fabricating zirconia-based dental restorations. It allows for manufacturing ceramic components with nearly unlimited geometries compared to traditional subtractive manufacturing technology. In order to explore its potential for fabricating dental prosthesis and determine its clinical indications, it is essential to investigate its microstructural characteristics and mechanical behavior. In this study, yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) fabricated by stereolithographic additive manufacturing, namely DLP acquired favorable flexural strength close to that of conventional subtractive-manufactured Y-TZP as indicated by uniaxial (three-point bending) and biaxial (ring on ring) tests, though the Weibull modulus of DLP-manufactured zirconia was lower than that of subtractive-manufactured zirconia. The strength predicting approach that uses effective area calculations was found to be applicable for both DLP-manufactured zirconia and subtractive-manufactured zirconia. Though both materials showed similar microstructures considering grain size and phase composition, significant differences in critical defects were observed. [ABSTRACT FROM AUTHOR]

In the present study, mechanical properties of 0.25Li2O.2SiO2-0.75BaO.2SiO2 glass-ceramic were investigated. The trans-formations‘ temperatures were determined by DTA instrument. The optimum nucleation temperature was found to be 540°C. This suggested the crystallization temperatures as 675, 720 and 800°C. After carrying out crystallization heat treatments, Vickers indentation test was applied. In order to determine the indentation fracture toughness (KIC), crack half-length ‚c‘ of the samples was measured. To calculate KIC, Young’s modulus, E and the measured hardness, Hv were used. Using KIC and probability of fracture ‚P‘, ln ln[1/(1 − P)] – ln KIC graph was drawn based on the Weibull distribution equation. Consequently, Weibull modulus, ‚m‘ and scale parameter, ‚K0‘ were determined and compared with each other.

Three‐layer silicon carbide (SiC) cladding architectures are considered to be promising materials for current light‐water nuclear reactors. Herein, a novel processing approach was proposed to fabricate dense three‐layer SiC tubes by introducing SiC nanowires (NWs) on the graphite rod, which resulted in change in the valley‐peak structure of SiCf tubular preform. A dense three‐layer‐NWs SiC cladding tube, consisting of a chemical vapor infiltration (CVI)‐SiC inner layer, a CVI‐SiCf/SiC composite layer, and a CVI‐SiC outer layer, was obtained through CVI process. Microstructure and hoop strength of the as‐obtained three‐layer‐NWs SiC cladding tube were systematically investigated. By avoiding delamination of the layers and reducing the pores, the three‐layer‐NWs SiC cladding tube exhibited an average hoop strength of 316.6 MPa with a Weibull modulus of 11.55. [ABSTRACT FROM AUTHOR]