Reduction In Strength Research Articles

Rubbercrete as a sustainable solution for recycling waste tires in concrete: An overview

Due to the rapid growth of the automotive industry, the number of waste tires has been rising dramatically each year. This increase is causing a strain on landfills, as the bulky nature of waste tires, with about 75% of their volume being void, quickly depletes available space of landfills. Furthermore, waste tires are non-biodegradable and, due to their concave shape, provide an ideal breeding ground for insects and harmful rodents, posing a public health risk. Given the limited range of products that can be produced from recycled tires, it is crucial to find economically viable solutions to recycle these tires and use them in mass production of useful materials, such as concrete. Concrete has been chosen by researchers as it is the second most consumed material per capita, after water. Researchers have produced crumb rubber from recycled tires and used it to partially replace fine aggregates in concrete, creating a material known as rubbercrete. Compared to conventional concrete, rubbercrete has better thermal and acoustic properties, is lighter in weight, and more ductile. However, it also shows a reduction in mechanical strengths. This paper provides an overview of rubbercrete, highlighting its key challenges, advantages, and properties.

Mechanical strength analysis of bio composite made by using micro powder made of Prosopis cineraria wood

The Present study examines the mechanical strength of bio-composites fabricated from wood powder of Prosopis cineraria (Khejri) and jute fiber as reinforcement inside an epoxy resin matrix. The mechanical performance of these bio-composites was assessed by altering filler content percentages (0%, 4%, 8%, 12%, 16%, and 20%) and filler particle sizes (250 microns and 500 microns) under standard and carbonate conditions. Tensile strength and impact energy assessments were performed to evaluate the effects of filler content, particle size, and filler type on the mechanical characteristics of the composites. The tensile strength tests reveal that composites with 12% filler and a particle size of 250 microns had the maximum tensile strength, measuring 33.4 MPa under normal settings and 34.8 MPa under carbonate conditions. An increase in filler content over 12% resulted in a reduction in mechanical strength due to filler agglomeration, which decreased stress transfer efficiency. The composites with 250-micron particles consistently demonstrated superior tensile and impact strengths compared to those with 500-micron particles, due to the increased surface area of the smaller particles. Comparative analysis of normal and carbonate conditions demonstrated that carbonate fillers offered superior reinforcement owing to their increased density and enhanced matrix-filler interaction, leading to augmented tensile and impact strength. These findings provide significant insights into the development of bio-composites for structural applications, namely in improving their mechanical strength and durability.

Effect of Waste Glass Powder Replacement of Hydraulic Lime on Properties of Natural Hydraulic Lime Mortars

This paper investigates the effects of the partial replacement of natural hydraulic lime (NHL) with waste glass powder (GP) on the physical, mechanical, and microstructural properties of NHL mortars. In the experimental study, five mixtures containing up to 50% GP were prepared to evaluate its effect on the flow, carbonation, unit weight, water absorption, porosity, ultrasonic pulse velocity, capillary water absorption, compressive strength, and microstructure of NHL mortars. The experimental results suggest that the partial replacement of NHL with GP significantly affects the properties of NHL mortars. A reduction in compressive strength was observed with increasing GP content in mortars at both early and later stages. Nevertheless, the compressive strength difference between samples containing 50% GP and the reference was found to be relatively minor at 91 days, implying an enhanced pozzolanic reaction over time. The incorporation of GP improved the consistency and capillary water absorption of mortars, while the opposite was observed for ultrasonic pulse velocity, porosity, and water absorption. The microstructural analysis revealed distinct changes in the structure of samples incorporating GP. The partial substitution of hydraulic lime with GP could be beneficial in reducing the CO2 emissions of NHL mortars.

Post-Fire Stability Bearing Capacity of I-Shaped Aluminum Alloy Members Under Axial Compression

Compared to steel structures, aluminum alloy structures are more susceptible to fire damage. Accurately evaluating the residual bearing capacity of fire-damaged aluminum alloy members is crucial for effective post-disaster management. Therefore, this paper investigates the post-fire bearing capacity of I-shaped aluminum alloy members under axial compression. First, a post-fire test on 16 I-shaped aluminum alloy members under axial compression was carried out. The test results indicate that all specimens fail by the minor axis flexural buckling, and the bearing capacity of the specimens decreases with the increase of the slenderness ratio. Moreover, a trilinear relationship is found between bearing capacity and post-fire temperatures. Second, finite element (FE) models are established using ABAQUS and validated against the test results. Subsequently, numerical analysis is carried out, considering various aluminum alloy brands, post-fire temperatures, slenderness ratios, initial geometrical imperfections, and cross-section dimensions. Through the statistical regression technology and the introduction of strength and stability-bearing capacity reduction coefficients, the formulae for estimating the post-fire stability-bearing capacity of I-shaped aluminum alloy members under axial compression are derived. Finally, the proposed formulae are verified to be accurate through error analysis.

Study on the deterioration of mechanical properties of stainless steel S35657 exposed to overall stage of fire

Fires often have destructive effects on steel structures, putting the safety of building structures at serious risk. As a new austenite stainless steel, grade S35657, its in-fire and post-fire mechanical behavior has not been reported, which limits its application. In this paper, a total 68 stainless steel S35657 coupons were designed and tested, with 34 coupons used for in-fire tests and 34 for post-fire tests. The effects of heating temperatures, loading rates, and heating soaking times on the mechanical properties were investigated. The failure modes, as well as the stress-strain curves and mechanical properties, were acquired. Electron microscopy scanning analysis were also conducted on the coupons to study the fracture mechanisms at elevated temperatures. The test results showed a rapid decline in in-fire mechanical properties when the temperature exceeded 600 °C. The yield strength of the coupon at 1000 °C is only 9.1 % of that at room temperature. As the tensile rate increased, the strength of the coupon increased gradually. For post-fire coupons, there is no significant change in the mechanical properties of coupons at temperatures ranging from 20 °C to 900 °C. However, after reaching a temperature of 1000 °C, the coupon experienced a reduction in yield strength (up to 27.8 %) and an expansion in elongation (up to18.0 %), compared to the coupon at ambient temperature. This related to the change in grain size of the coupons after exposure to high temperatures. The heating soaking time has an insignificant effect on the post-fire mechanical properties of stainless steel S35657. Existing constitutive models in the literature cannot be well applied to stainless steel S35657, new constitutive models to predict the in-fire and post-fire mechanical properties have been established. Moreover, reduction factors for the key mechanical properties were compared with existing values, and new unified equations for stainless steel S35657 were proposed. Finally, a reliability analysis was performed to evaluate the proposed design rules, and it was deemed that the proposed design rules were reliable. The findings of this study will provide a reference for engineers in evaluating the in-fire and post-fire residual strength of stainless steel S35657, and offer guidance for fire resistance design and high-temperature repair reinforcement.

Effect of pre-exposure to chloride environment on the tensile deformation of SS 304HCu at 973 K

304HCu austenitic stainless steel (SS 304HCu) with 3 % copper content is utilized as the tubing material for advanced ultra-supercritical boilers, which operate at temperatures around 973 K and a pressure of 31 MPa. The current investigation aimed to examine the influence of prior exposure to an acidic chloride environment on the tensile characteristics of SS 304HCu at 973 K with the nominal strain rate of 1× 10−3 s−1 in solution annealed as well as thermally aged (973 K/10000 h) conditions. In the prior exposure condition, both the solution annealed and aged specimens were subjected to a pre-determined potential of −0.14 V (Ag/AgCl) for 48 h in 5 M NaCl + 0.15 M Na2SO4 + 2 ml HCl solutions. Thermally aged SS 304HCu showed lower strength in both true UTS and true yield strength compared to the solution annealed specimen tested at 973 K. Exposure to an acidic environment resulted in a considerable reduction in tensile strength and uniform plastic strain. For all the conditions, saturation-stress-based relationship was employed to describe the flow behaviour of the alloy. The relationship adequately fits the true stress-true strain data of SS 304HCu. A systematic variation in strain hardening parameters with respect to different test conditions is noticed. In the case of the aged alloy, the observed microstructure revealed the presence of M23C6 at grain boundaries and copper precipitates in the grain interior. The increased chromium depletion and the higher degree of sensitization led to the formation of localized pits in pre-exposed aged specimen conditions. Consequently, the synergistic influence of precipitation and pitting corrosion significantly affected the tensile deformation behaviour of SS 304HCu alloy in the aged and pre-exposed condition compared to the solution annealed condition.

Interface engineering to construct heterostructured MoO3/SmMn2O5 for chemical looping oxidative dehydrogenation of ethane

Electronic structure and lattice oxygen in metal oxides play important roles in the chemical looping oxidative dehydrogenation of ethane. Herein, an interface strategy is proposed to tailor electronic structure and activate lattice oxygen of mullite SmMn2O5 via the interface fabrication with MoO3 for enhancing the reactivity of the sample. The optimized 2MoO3/SmMn2O5 oxygen carrier exhibited 50 % ethane conversion and 83.9 % ethylene selectivity higher than that of pure SmMn2O5 and pure MoO3. Density functional theory simulations and characterization results revealed that the interface of MoO3/SmMn2O5 regulated the d-band center, which tailored the adsorption of ethane. Besides, the interface of MoO3/SmMn2O5 also caused the charge transfer from Mn atoms in SmMn2O5 to O atoms in MoO3 and SmMn2O5, leading to a reduction of the Mn-O bond strength and an enhancement in the activity of the lattice oxygen and Oads. This study provides useful insights to regulate electronic structure and activate lattice oxygen of oxygen carrier through interfacial engineering for the practical application of ethane chemical looping oxidative dehydrogenation.

Experimental Study on the Mechanical Properties of Basalt Fiber Geogrids Reinforced with Cement-Stabilized Macadam

Cement-stabilized crushed stone is widely used in the construction of high-grade highways because of its good durability and stability. However, cement-stabilized gravel is also easily affected by temperature and humidity, resulting in a reduction in the overall strength and durability of asphalt pavement. In response to this problem, in this study, we lay a single layer of a basalt fiber geogrids in a cement-stabilized gravel base of a test section of the Yan-Chong Expressway. The bonding and friction forces formed between the basalt fiber geogrids and the base as well as the mechanical bite force, play an anti-cracking role. We conducted a comparative experimental study on the mechanical properties of basalt fiber geogrids reinforced or not reinforced with cement-stabilized gravel specimens of different ages. The results showed that (1) the unconfined compressive strength of cement-stabilized gravel was slightly reduced; (2) the splitting strength was somewhat improved; (3) the compressive elastic modulus was slightly reduced; (4) the flexural and tensile strengths were significantly increased. An improvement in the crack resistance in semi-rigid base materials can improve the service life of high-grade asphalt pavements.

The Benefits of a Rehabilitation Program Following Medial Patellofemoral Ligament Reconstruction

The medial patellofemoral ligament (MPFL) is critical for patellar stability. This study investigates the efficacy of a one-year physical therapy rehabilitation program following MPFL reconstruction using Synthetic Graft (SG) and Quadriceps Tendon Autograft (QTA). Thirty-five patients aged 18–38 underwent MPFL reconstruction (20 SG, 15 QTA). They participated in a structured rehabilitation program to improve their range of motion (ROM), muscle strength, pain management, and overall quality of life (QoL). The program included physiotherapy and MLS laser, Game Ready Therapy, EMS, TENS, TECAR, and lymphatic drainage. Before and after the program, assessments included knee flexion and extension using goniometry, muscle strength via the Medical Research Council (MRC) scale, knee circumference, pain intensity on the Visual Analogue Scale (VAS), and QoL with the EQ-5D instrument. Significant improvements were observed in knee flexion (37.57° vs. 114.71°, p < 0.001), muscle strength (MRC scale 1–4 points vs. 4–5 points, p < 0.001), and pain reduction (VAS 6.66 vs. 0.46, p < 0.001). The functional coefficient of mobility and QoL scores also markedly increased. Patients with QTA improved some parameters better than those with SG. These findings support the effectiveness of a comprehensive rehabilitation program in enhancing knee functionality, reducing pain, and improving QoL post-MPFL reconstruction. Personalized rehabilitation protocols are recommended to optimize recovery outcomes.

Theoretical and Experimental Analyses of the Interfacial Mechanism of Dendrimer-Doxorubicin Complexes Formation.

The work presents correlations between the physicochemical properties of the carrier and the active substance and optimization of the conditions for creating an active system based on PAMAM dendrimers and doxorubicin. The study monitored the influence of the ionized form of the doxorubicin molecule on the efficiency of complex formation. The deprotonated form of doxorubicin occurs under basic conditions in the pH range of 9.0-10.0. In the presence of doxorubicin, changes in the zeta potential of the complex concerning the initial system are observed. These changes result from electrostatic interactions between the drug molecules and external functional groups. Based on changes in the absorbance intensity of UV-vis spectra, the binding of the drug in the polymer structure is observed depending on the pH of the environment and the molar ratio. Optimal conditions for forming complexes occur under alkaline conditions. UV-vis, Fourier transform infrared spectroscopy, and circular dichroism spectroscopy confirmed the stability of the formed dendrimer-DOX complex. Molecular dynamics simulations were conducted to gain a deeper insight into the molecular mechanism of DOX adsorption on and within the G4.0 PAMAM dendrimers. It was observed that the protonation state of both the dendrimer and DOX significantly influences the adsorption stability. The system exhibited high stability at high pH values (∼9-10), with DOX molecules strongly adsorbed on the dendrimer surface and partially within its bulk. However, under lower pH conditions, a reduction in adsorption strength was observed, leading to the detachment of DOX clusters from the dendrimer structure.

Axial compressive properties of round bamboo-fiber reinforced phosphogypsum composite short columns

Bamboo is an ideal green building material with excellent mechanical properties. Phosphogypsum (PG) is a kind of solid waste residue which is in urgent need of resource utilization and has been used as construction material. In this paper, a kind of round bamboo-fiber reinforced phosphogypsum composite short column was proposed. Axial compression tests of pure bamboo columns, bamboo columns filled with phosphogypsum inside, bamboo columns with phosphogypsum outside and bamboo columns with phosphogypsum inside and outside were carried out to explore the failure mode and mechanical properties of the short columns. The effects of the parameters include bamboo node, hose hoops, size of the bamboo tube and the strength of phosphogypsum on the mechanical properties of the short columns were analyzed, and the theoretical calculation method of the bearing capacity of the short columns was put forward. The results show that the bamboo nodes and hose hoops can improve the bearing capacity, initial stiffness and ductility of the column. The larger the size of the bamboo tube, the better the mechanical properties of the short column. The bearing capacity of round bamboo—phosphogypsum composite short column is higher than that of pure bamboo column. The ductility of bamboo columns with phosphogypsum outside is obviously higher than that of pure bamboo columns. The finite element analysis results are in good agreement with the test results. The theoretical calculation method of the bearing capacity of columns considering the strength reduction coefficient, the bamboo node effect coefficient and the constraint effect in this paper has high accuracy.

A holistic study of the effect of geometrical and processing conditions on the static mechanical performance of LPBF strut elements

Laser powder bed fusion (LPBF) enables geometrical designs of great complexity, such as metamaterials. These structures are founded on elemental struts printed at various orientations and sizes. Understanding how these design variables affect mechanical properties is crucial for optimizing component performance. This work aims to systematically investigate the impact between these design variables on defects, roughness, geometrical deviations, and microstructure of Ti-6Al-4V elemental struts and correlate them with mechanical properties. The analysis shows that smaller strut diameters present an increased sensitivity to defects, reducing ductility by 45.8% on average as the diameter decreases from 1.5 mm to 0.5 mm. When compared to vertical struts, horizontally printed struts of 1.5 mm, 1 mm, and 0.5 mm present on average a respective reduction in ductility of 57.4%, 59.8%, and 70.9%, and a respective reduction in the ultimate strength of 13.3%, 24.5%, 61.2%. This has been associated with warping and increased roughness caused by dross formation. Finally, the study shows the complex interaction of process parameters' effect with the struts' orientation and size. These findings pose the basis for a more accurate and optimal mechanical design of cellular metamaterials, from the underlying material perspective.

Recycled Aggregates Influence on the Mechanical Properties of Cement Lime-Based Mortars

The current framework for managing construction waste, guided by European Union regulations, calls for an integrated waste management system. However, the reuse of old plaster waste, particularly from deteriorated facades, remains underexplored. This study investigates the potential of repurposing old plaster waste as a substitute for aggregates and cement in mortars, with the aim of promoting environmental sustainability and resource efficiency. Three mortar mixes were analyzed: a control mix, a mix with 45% waste replacing aggregates, and a mix with 10% waste replacing cement. Results show that replacing 45% of aggregates with plaster waste led to a 30% reduction in flexural strength, while the 10% cement replacement increased flexural strength by 6%. Compressive strength dropped by 27% and 38% for cement and aggregate replacements, respectively. Despite these reductions, the waste replacement remained within acceptable limits for structural integrity. Further microscopic analysis revealed that the incomplete integration of portlandite particles from the waste contributed to non-uniform bonding and crystal formation, weakening the mortar’s structure. This research demonstrates the feasibility of reusing old plaster waste, offering a novel approach to reducing construction waste and promoting a circular economy. It contributes to filling the knowledge gap on the reuse of plaster mortars while aligning with sustainable construction goals.

Effect of carbon nanotube incorporation on the mechanical and physical properties of hydroxyapatite/glass ionomer nanocomposite

This manuscript discusses the potential use of multi-walled (MW) carbon nanotubes (CNTs) as a filler material in hydroxyapatite/glass ionomer cement HA/GIC nanocomposite to enhance its properties: mechanical and physical. Four different proportions (1, 2, 3, and 5 wt%) of CNTs were added to the HA/GIC nanocomposite to determine the optimum ratio that can lead to the best properties of the new nanocomposite biomaterial. Mechanical mixing technique followed in dentistry was used in preparing all samples. FTIR, PSA, XRD, TEM, and SEM were used to characterize the fabricated Pellets. In addition, the new nanocomposite samples were evaluated using compressive and diametral tensile tests. Overall, increasing the weight ratio of CNTs added to the nanocomposite (from 1 to 5 wt%) caused about a 40% reduction in the compression strength of the samples. However, a slight increase (about 4%) was detected at 2 wt% CNTs samples. Also, a distinct increase in the elasticity of the composite (about 50%) was reported. The best results of diametral tensile strength were found at a 3 wt% CNTs. Furthermore, for all samples, adding CNTs to the composite changed the sample’s color from A2 and B2 to totally black color.

Microstructural and mechanical properties of high-strength geopolymer based on Martian soil simulant

Geopolymers made from simulated Martian regolith would suffer from exhibit poor engineering properties, rendering them unsuitable as base materials. To improve the mechanical properties of geopolymers, this study prepared a new Martian soil simulant named DH-1. DH-1- based geopolymers were synthesized using Al2O3 (Al group) and metakaolin (MK group) as modifying agents. The durability of geopolymers with ultraviolet (UV) radiation was assessed under simulated Martian atmospheric conditions. The results indicated that the UCS and FS of both the Al and MK groups increased with curing time, with maximum UCS and FS of 55.27 MPa and 15.16 MPa, respectively. The UCS and FS of the Al and MK groups exhibited a two-phase change. The inflection points for rapid to slow in the UCS and FS occurred on day 28 for the Al group and day 14 for the MK group. The addition of Al2O3 and metakaolin promoted the replacement of silicon atoms by aluminum atoms in the silica-oxygen group, producing more gels product. After UV irradiation, the UCS and FS of the geopolymer decreased by 13 % and 44 %, respectively. Furthermore, the geopolymers underwent carbonation, with new cracks forming due to the combined effects of UV exposure, causing strength reduction.

Effect of water to cement ratio on mechanical properties of FRC subjected to elevated temperatures: Experimental and soft computing approaches

The deterioration of concrete is greatly dependent on the cracks and microcracks development owing to loading or environmental influences. An effective step to avoid the spread of cracks and microcracks is employing of different fibers in concrete and the manufacture of fiber reinforced concrete. On the other hand, fire is one of the cases that always threatens engineering structures. Elevated temperatures cause obvious chemical and physical changes that lead to concrete deterioration. In this study, the effect of adding various fiber with different volume contents in concrete mixture with various cement content was evaluated experimentally. Results indicate that spalling was more dominant in mixture containing steel fiber and with higher amount of cement, while there is not any spalling in mixture containing polypropylene (PP) fibers. Moreover, the reduction in tensile strength of fiber-free concrete specimens is less pronounced in mixtures with higher cement content. In addition, the positive performance of PP fibers compared to steel fibers was proved at higher temperatures and cement contents. Furthermore, by conducting a comprehensive and accurate survey, this research pinpoints gaps in the current literature. Moreover, the gathered dataset serves as input for training a machine learning approach known as Group Method of Data Handling (GMDH). The GMDH network demonstrates a satisfactory accuracy in predicting experimental results, with a MSE of 0.0044.

Elucidating factors on the strength of carbonated compacts: Insights from the carbonation of γ-C2S, β-C2S and C3S

Accelerated carbonation presents a promising approach for enhancing the early strength of cement-based materials while simultaneously sequestering CO₂. This study examines the carbonation of γ-C₂S, β-C₂S, and C₃S compacts to identify the critical factors influencing strength development over extended curing periods. Analysis of the evolution of mechanical properties, microstructure, and phase assemblages reveals three key factors: 1) Degree of carbonation, which directly correlates with the density of the compacts; 2) Crystalline form and crystal size of calcium carbonate, influencing the strength of the crystal interface; and 3) Silica gels, which act as a phase boundary, with hydration products forming in the later stages of β-C₂S carbonation potentially affecting strength. The findings indicate that calcite promotes rapid strength gain in the early stages, while aragonite contributes to long-term performance. The presence of hydration products within the silica gel phase boundary may explain the observed strength reduction in β-C₂S compacts during extended carbonation. These insights provide valuable guidance for optimizing the design and application of carbonated cement-based materials for sustainable construction.

Effect of thermal shocks on the interfacial bond strength of sandwich composites built with rigid and soft materials produced through extrusion process

The mechanical behavior and adhesion strength of the sandwich composite, which consists of a flexible and a rigid material, were examined using extruded polylactic acid (PLA) and thermoplastic polyurethane (TPU). Three types of binders were combined with the appropriate hardeners to bond the extruded materials. The fabricated specimens are subjected to a different number of thermal shock cycles, with a maximum and minimum temperature of 80 °C and −18 °C, respectively. The sandwich composite's mechanical properties, including tensile, flexural, and impact strength, were assessed after 20, 40, and 80 cycles of thermal shock. The results indicated that the ductility of PLA material was significantly impacted by the thermal shock cycles. After completing the maximal thermal shock cycles, the composites joined with polyester resin exhibited a lower strength reduction in the impact specimens. Maximum tensile strength of 22.3 MPa, flexural strength of 31.6 MPa, and impact strength of 8.3 J were recorded prior to the application of thermal shocks to the specimens. The specimens that were bonded with epoxy resin recorded the maximal tensile, flexural, and impact strength. Following the thermal shock cycles, the composites bonded with epoxy resin exhibited a lesser reduction in tensile and flexural strength, while the composites bonded with polyester resin showed a lower strength reduction for impact specimens. The tensile and flexural specimens encountered a 7.54 % and 20.24 % reduction in strength, respectively, after undergoing 80 cycles of thermal shocks. The impact specimens experienced an 8.62 % reduction in strength.

A Novel Strength Reduction Method for a Slope Stability Assessment Based on a Finite Element Method

Ensuring the stability of slopes is critical to the safe operation of geotechnical engineering. Evaluating slope stability to minimize geologic risks induced by destabilization is significant in reducing casualties and property damage. A conventional, single-coefficient strength reduction method is widely applied in slope stability analyses, but this method ignores the attenuation degree of different parameters in the slope destabilization. A new double-strength reduction method considering different contributions of the mechanics’ parameters is proposed in this study for evaluating the stability of nonhomogeneous slope. First, the role of each mechanic’s parameters in the slope destabilization was investigated theoretically and numerically using ABAQUS software 2022. The results indicate that the effect of elasticity (E), Poisson’s ratio (v), and soil gravity (γ) on the evolution of factor of safety (FOS) are insignificant and can be neglected compared with cohesive force (c), and angle of internal friction (φ). Next, an improved method was constructed to correlate the FOS with cohesive force (c) and the angle of internal friction (φ). Then, a numerical method was constructed based on the computation of the mathematical–mechanical relationship between FOS and the mechanical parameters, and the stability of slope is estimation based on the Mohr–Coulomb yield criterion. Finally, the double-strength reduction coefficient method proposed in this study, the limit equilibrium method, and the traditional finite element strength reduction coefficient method were applied to nonhomogeneous slopes and slopes containing a soft underlying layer for comparison, and the difference between them was within the range of ±5%. The results indicate that both the limit equilibrium method and the traditional finite element strength reduction method tend to overestimate the FOS of intricate slopes compared with the evaluated method proposed in this study. This parallel comparison serves to validate the accuracy of the double-strength reduction method proposed in the present study. Further, based on the proposed method, the relationship between slope stability and slope displacement is established, which provides a theoretical basis for the safety assessment of slope engineering.

Compression-after-indentation study of alumina-based oxide/oxide ceramic matrix composite with variable damage

In this study, the damage tolerance of alumina-based Oxide/Oxide ceramic matrix composite with varying extent of quasi-static indentation damage is evaluated via compression test. Pre-existing damage in the laminates are of different sizes and exist in the form of delaminations, fiber fracture, matrix cracking, and major through-thickness cracks. Digital image correlation is used to monitor the in-test displacements and strain field. When compared to undamaged compressive strength, the strength reduction in the indented specimens range from 52 % to 57 %. This shows that the compression after indentation strength is not significantly affected by variations in the extent of indentation damage. Digital image correlation results showed out-of-plane deformation originating from the indented region that grew stably with increasing load to a critical phase, beyond which they became significantly large. This resulted in the sudden catastrophic failure of the laminate, apparently caused by delamination buckling. This was confirmed by post-test X-ray computed tomography micrographs.