Elastic Strength Research Articles

Optimization of mechanical properties and dimensional stability of densified wood using response surface methodology

Wood has gained popularity as a building and decorative material due to its environmentally friendly and sustainable characteristics. Yet, its long maturation time poses a limitation on meeting the growing demand for wood products. This challenge has led to the plantation of fast-growing wood as an alternative solution. Unfortunately, the poor mechanical properties of fast-growing wood hinder its application. In this study, we developed novel densification-modified wood by combining alkali chemical pretreatment, cyclic impregnation, and mechanical hot-pressing techniques. Additionally, the response surface method was employed to rapidly determine the optimal preparation parameters, reducing the cost of preparation under various conditions. The optimized parameters resulted in densification-modified wood with a flexural strength and modulus of elasticity of 337.04 MPa and 27.43 GPa, respectively. Furthermore, the densified wood achieved excellent dimensional stability by reducing the water-absorbing thickness swelling to 1.15 % for 72-h water soaking. The findings indicated that the densification-modified wood possessed high tensile strength and elastic modulus, along with excellent dimensional stability. The proposed densified wood modification technology in this study offers new perspectives and design guidance for the application of outdoor engineering structures, energy-efficient buildings, and decorative materials.

Linear Contact Load Law of an Elastic–Perfectly Plastic Half-Space vs. Sphere under Low Velocity Impact

The impact of contact between two elastic–plastic bodies is highly complex, with no established theoretical contact model currently available. This study investigates the problem of an elastic–plastic sphere impacting an elastic–plastic half-space at low speed and low energy using the finite element method (FEM). Existing linear contact loading laws exhibit significant discrepancies as they fail to consider the impact of elasticity and yield strength on the elastic–plastic sphere. To address this limitation, a novel linear contact loading law is proposed in this research, which utilizes the concept of equivalent contact stiffness rather than the conventional linear contact stiffness. The theoretical expressions of this new linear contact loading law are derived through FEM simulations of 150 sphere and half-space impact cases. The segmental linear characteristics of the equivalent contact stiffness are identified and fitted to establish the segmental expressions of the equivalent contact stiffness. The new linear contact loading law is dependent on various factors, including the yield strain of the half-space, the ratio of elastic moduli between the half-space and sphere, and the ratio of yield strengths between the half-space and sphere. The accuracy of the proposed linear contact loading law is validated through extensive Finite Element Method simulations, which involve an elastic–plastic half-space being struck by elastic–plastic spheres with varying impact energies, sizes, and material combinations.

Biochar for sustainable additive manufacturing: Thermal, mechanical, electrical, and rheological responses of polypropylene-biochar composites

The utilization of eco-friendly reinforcing materials and the fabrication of sustainable composites with enhanced mechanical and electrical properties are a subject of great scientific interest. Such research is aiming to be applied in a variety of industrial applications. In this study, polypropylene (PP) was used as a matrix material and combined with biochar (BC) as a filler at different loadings (2.0, 4.0, 6.0, 8.0, and 10.0 wt %) to produce reinforced composites. Biochar was produced from olive tree prunings. Additively manufactured specimens underwent a variety of tests (fourteen in total) regarding their thermal, structural, mechanical, morphological, and electrical properties. The mechanical properties of the PP were improved by the addition of 4.0 wt % biochar, as the tensile strength and modulus of elasticity, presented a 28.4 % and 24.3 % increase compared to that of pure PP. Overall, the 6 wt % was the optimum loading considering all the tests conducted. The thermal stability of the PP/BC composites was significantly improved compared to that of pure PP. At a filler loading of 8.0 wt %, the dc-conductivity of PP/biochar composite increased by more than 9 orders of magnitude, suggesting the existence of a percolation threshold, above which the polymer composite switches from insulating behavior to a conductive state. Overall, biochar addition had a positive impact on all measured quantities and proved to be an eco-friendly material suitable for use in various applications of additive manufacturing (AM).

Ultrasonic pulse velocity as a non-destructive measure for the projectile impact resistance of cementitious composites across a wide range of mix compositions

This paper presents an investigation on the applicability of using ultrasonic pulse velocity (UPV) as a non-destructive measure for characterizing high velocity projectile impact (HVPI) resistance as well as physical/mechanical properties of cementitious composites across a wide range of mix compositions. Ultra-high performance concretes (UHPCs), engineered cementitious composites (ECCs), concretes, mortars and cement pastes with compressive strengths ranging from 34.2 MPa to 220.2 MPa and elastic moduli ranging from 17.1 GPa to 104.2 GPa are considered for investigation. Projectile impact resistance of cementitious composites is evaluated in terms of the depth of penetration (DOP) and equivalent crater diameter (ECD). Physical/mechanical properties, including compressive strength, static and dynamic moduli of elasticity, density, hardness, splitting tensile strength, compressive and flexural toughnesses, are investigated. The UPV is found to be a promising non-invasive and non-destructive measure for the DOP characterization, since both the UPV and DOP are governed by the weighted properties of underlying constituent materials (e.g. matrix and fine/coarse aggregate). In comparison to the DOP, the correlation between the ECD and UPV is relatively weak. The results indicate that there exists a strong correlation between the UPV and the elastic modulus/density/hardness of cementitious composites. It is also found that commonly used two-phase composite models can predict the UPV of concrete with good accuracy.

Evaluation of Timber Degradation Caused by Insects to Quantify the Mechanical Strength of Load-Bearing Elements

ABSTRACT Timber elements within historic structures are often susceptible to biological decay caused by insects. The areas affected by insect attacks are typically not considered in the structural analysis, although they may still provide some strength. Hence, accurately assessing the extent and intensity of insect damage is crucial for determining the actual strength of timber members. The present work presents the results obtained on insect-damaged timber members that were evaluated based on the proportion of the surface area occupied by bore holes, a method that is readily applicable by skilled operators during on-site inspections. Resistance to penetration (by drilling) and standard mechanical tests were then carried out to measure density in addition to strength (compression, shear, bending) and modulus of elasticity in bending. The results evidenced moderate yet highly significant inverse correlations between degree of degradation and mechanical properties. In contrast, density showed no discernible correlation with the degree of decay, nor did penetration resistance. However, drilling resistance showed a robust correlation with density and mechanical characteristics. The coupling between visual assessment of decay and evaluation of resistance to penetration allowed accurate prediction of mechanical properties similar to healthy wood.

Characterization and Implementation of Cocoa Pod Husk as a Reinforcing Agent to Obtain Thermoplastic Starches and Bio-Based Composite Materials.

When the cocoa pod husk (CPH) is used and processed, two types of flour were obtained and can be differentiated by particle size, fine flour (FFCH), and coarse flour (CFCH) and can be used as a possible reinforcement for the development of bio-based composite materials. Each flour was obtained from chopping, drying by forced convection, milling by blades, and sieving using the 100 mesh/bottom according to the Tyler series. Their physicochemical, thermal, and structural characterization made it possible to identify the lower presence of lignin and higher proportions of cellulose and pectin in FFCH. Based on the properties identified in FFCH, it was included in the processing of thermoplastic starch (TPS) from the plantain pulp (Musa paradisiaca) and its respective bio-based composite material using plantain peel short fiber (PPSF) as a reinforcing agent using the following sequence of processing techniques: extrusion, internal mixing, and compression molding. The influence of FFCH contributed to the increase in ultimate tensile strength (7.59 MPa) and higher matrix-reinforcement interaction when obtaining the freshly processed composite material (day 0) when compared to the bio-based composite material with higher FCP content (30%) in the absence of FFCH. As for the disadvantages of FFCH, reduced thermal stability (323.57 to 300.47 °C) and losses in ultimate tensile strength (0.73 MPa) and modulus of elasticity (142.53 to 26.17 MPa) during storage progress were identified. In the case of TPS, the strengthening action of FFCH was not evident. Finally, the use of CFCH was not considered for the elaboration of the bio-based composite material because it reached a higher lignin content than FFCH, which was expected to decrease its affinity with the TPS matrix, resulting in lower mechanical properties in the material.

Experimental study on properties of cinder aggregate lightweight concrete with fibre reinforcement

Lightweight concrete is gaining increasing significance in the construction industry due to its numerous advantages over conventional concrete. It can be produced by partially or fully replacing conventional coarse aggregates with lightweight aggregates. Laboratory tests were conducted to assess the feasibility of utilizing solid waste, such as cinders, for manufacturing lightweight aggregate concrete. The mechanical properties of cinder aggregate lightweight concrete were improved through the introduction micro-reinforcements. Polypropylene fibres were incorporated as micro-reinforcements at volume fractions of 0.1%, 0.2%, 0.3%, and 0.4%. The experimental results, including compressive strength, flexural strength, and modulus of elasticity, demonstrated that waste cinder aggregates can effectively replace coarse aggregates in lightweight concrete. Furthermore, the incorporation of polypropylene fibres enhances the mechanical performance of cinder aggregate lightweight concrete.

Nano‐enhanced epoxy sandwich composites: Investigating mechanical properties for future aircraft construction

AbstractThe aviation sector is continually seeking ways to reduce the weight of aircraft structures without compromising their mechanical integrity. Lightweight materials, such as advanced epoxy sandwich composites with hybrid nanostructures, have the potential to significantly contribute to fuel efficiency, thereby addressing environmental concerns and operational costs. This research investigates the mechanical properties of hybrid sandwich polymer composites filled with silica nanoparticles (SNiPs). Epoxy isocyanate (PU) foam sandwich composites were fabricated with kevlar fiber, carbon fiber, and glass fiber, constructed by alternating inclined interply bidirectional fiber and foam layers. SNiPs were introduced into the composite system at varying percentages, such as 0, 2, 4, and 6 wt%. The study employs a systematic approach, incorporating experimental testing, to assess key mechanical parameters, including tensile strength, flexural strength, and shear strength. The test results indicate that the incorporation of SNiPs improved the mechanical properties of the composites, leading to enhanced strength, toughness, and modulus of elasticity. Incorporation of composite laminates with 4 wt% SiNPs resulted in improved three‐point bending, tensile, shear, and torsional strengths, with maximum values of ca. 64, ca. 5, ca. 2 MPa, and ca. 22 Nm, respectively. The findings contribute to the ongoing pursuit of materials that can meet the stringent demands of modern aviation, ultimately paving the way for advancements in aircraft construction and design.

Multi-variate multi-objective optimization of production conditions for electro-spun skin scaffold using RSM and investigation of gamma irradiation effects on the properties of the optimized sample

Developing electro-spun scaffolds with ideal mechanical properties for skin purposes can profit from using the Response Surface Methodology technique to define and optimize the outcome quality and required sterilization for use in vivo. This study investigated the effects of four main independent electrospinning variables for polycaprolactone nanofibers scaffold using multi-variable and multi-objective optimization. It was done to determine significant parameters on responses and find optimal conditions to reach the preferred properties. Young's modulus, elongation-at-break, and tensile strength were the responses. After obtaining appropriate models, the impact share of variables on the responses was determined using Sobol sensitivity analysis. The results showed that flow rate is the most significant parameter of elastic modulus and tensile strength responses, with 76.45 % and 41.27 % impact shares, respectively. The polymer concentration is the following significant parameter on elongation at break, tensile strength and, Young's modulus responses with 64.35 %, 39.485 and, 14.28 % impact share, respectively. Based on the optimized results, a skin scaffold with desired mechanical properties was achieved (under solution concentration of 10 % w/v, flow rate of 2 mL/h, nuzzle-collector distance of 15 cm, and applied voltage of 20 kV). Then it was sterilized with gamma radiation of various doses (25, 40, and 55 kGy) to use in vivo. The SEM analysis indicated no significant change in fibrous morphology due to gamma irradiation at any dosage. FTIR analysis demonstrated the breakup of ester bonds due to gamma irradiation. For samples irradiated by 25 kGy, the crystallinity percentage decreased and chains crosslinking without losing the mechanical stability was dominant. The studies demonstrated that 25 kGy of gamma irradiation could improve the mechanical properties of the optimized PCL skin scaffold, which is very promising for wound healing.

Goldene: An Anisotropic Metallic Monolayer with Remarkable Stability and Rigidity and Low Lattice Thermal Conductivity.

In a recent breakthrough in the field of two-dimensional (2D) nanomaterials, the first synthesis of a single-atom-thick gold lattice of goldene has been reported through an innovative wet chemical removal of Ti3C2 from the layered Ti3AuC2. Inspired by this advancement, in this communication and for the first time, a comprehensive first-principles investigation using a combination of density functional theory (DFT) and machine learning interatomic potential (MLIP) calculations has been conducted to delve into the stability, electronic, mechanical and thermal properties of the single-layer and free-standing goldene. The presented results confirm thermal stability at 700 K as well as remarkable dynamical stability of the stress-free and strained goldene monolayer. At the ground state, the elastic modulus and tensile strength of the goldene monolayer are predicted to be over 226 and 12 GPa, respectively. Through validated MLIP-based molecular dynamics calculations, it is found that at room temperature, the goldene nanosheet can exhibit anisotropic tensile strength over 9 GPa and a low lattice thermal conductivity around 10 ± 2 W/(m.K), respectively. We finally show that the native metallic nature of the goldene monolayer stays intact under large tensile strains. The combined insights from DFT and MLIP-based results provide a comprehensive understanding of the stability, mechanical, thermal and electronic properties of goldene nanosheets.

Thermomechanical behavior of auxetic lattices

This study investigates the thermomechanical behavior of auxetic square-grid lattice structures through analytical, numerical, and experimental approaches. These structures have gained prominence in biomedical applications due to their ability to mimic the structural behavior of surrounding tissue, even if the natural tissue is not auxetic. First, analytical relations are derived for elastic modulus, Poisson’s ratio, and yield strength of lattice structures, as well as their thermomechanical behavior under different loading conditions. The mechanical properties of lattice structures are validated using both finite element and experiments. Several 3D-printed specimens with varying thickness-to-length dimensions are heated in a heat chamber to measure their deformations. Results also demonstrate excellent accuracy of the derived analytical relationships, which show that elastic modulus and yield strength increase exponentially with an increase in the thickness-to-length (t/l) ratio, while Poisson’s ratio is largely independent of t/l. Furthermore, it is found that the coefficient of thermal expansion is equivalent to that of the constituent solid material and that thermal stress has a linear relationship with temperature change. These findings have important implications for analyzing lattice structures based on other unit cell types and can be extended to macro-geometries such as tubular or spherical shapes commonly used in biomedical applications.

Acrylamide‐Based Aramid‐Reinforced Soft Contact Lenses

In this study, manufacturing of acrylamide‐based soft contact lenses is attempted with high elastic modulus, tensile strength, water content, and oxygen transmissibility. For this purpose, colorless and transparent aramids are prepared using diamine monomers with strong electron‐withdrawing groups such as CF3 and sulfone groups. These aramids are used as reinforcing agents. These compounds are not only thermally and thermodynamically stable but also colorless, transparent, and mechanically very robust. They are very soluble in N,N‐dimethylacrylamide. Subsequently, reactive liquid resins are prepared simply by dissolving aramids in N,N‐dimethylacrylamide, and lenses are manufactured by the bulk polymerization of the liquid resins to which an appropriate amount of a crosslinking agent is added. Mechanically enhanced soft contact lenses are thus easily produced by the conventional manufacturing method. Some of the synthesized lenses maintain their original shape without phase separation even after hydration. These lenses have remarkably higher elastic modulus (up to 8.13 MPa) and tensile strength (up to 1.62 MPa) than the conventional lenses made of 2‐hydroxyethyl methacrylate (HEMA). The synthesized lenses also have a high water content (up to 83.0%) and oxygen transmissibility (up to 26.8 Dk t−1).

Effect of clay content on concrete properties

The presence of clay in aggregate is frequently associated with the deterioration of concrete properties. The objective of this study was to investigate the effects of varying clay contents on the mechanical properties, freeze-thaw resistance, permeability and water absorption behavior of concrete. Additionally, the differences in the permeability, and water absorption behavior of the surface layer and interior of concrete were comparatively analyzed using self-designed tests. The results indicate that the presence of a minimal quantity of clay did not diminish the compressive strength and static compressive modulus of elasticity of concrete. However, it did result in a reduction in the tensile properties and durability of concrete. Furthermore, the mechanical properties, freeze-thaw resistance, and anti-permeability of concrete were significantly diminished when the clay content reached 1.6%. Furthermore, this study proposed an innovative evaluation method for dividing the water absorption behavior of concrete into three stages, which more accurately reflected the trend of water absorption behavior in concrete. It was found that the sorptivity and permeable porosity of concrete in the three stages exhibited a strong correlation. The presence of clay increased the sorptivity and permeable porosity of concrete, with the most pronounced effect observed in the initial water absorption stage. Moreover, the permeable porosity of the interior of concrete was found to be reduced in comparison to that of the surface layer of concrete at all ages with varying clay contents, with the reduction ranging from 10.7% to 14.7%. In practical engineering construction, it is recommended that the clay content be kept within reasonable limits, and the effect of the clay content on the properties of the surface layer of concrete be given greater attention.

Potential of Reusing 3D Printed Concrete (3DPC) Fine Recycled Aggregates as a Strategy towards Decreasing Cement Content in 3DPC.

This paper explores the new potential strategy of using fine recycled aggregates (fRA) derived from waste 3D printed concrete (3DPC) as a substitute for cement in additive manufacturing. This study hypothesizes that fRA can optimize mixture design, reduce cement content, and contribute to sustainable construction practices. Experimental programs were conducted to evaluate the fresh and hardened properties, printability window, and buildability of 3DPC mixes containing fRA. Mixes with replacement rates of cement with fRA by 10 vol%, 20 vol%, 30 vol%, 40 vol%, and 50 vol% were produced. A comprehensive experimental protocol consisting of rheological studies (static and dynamic yield stress), dynamic elastic modulus determination (first 24 h of hydration), flexural and compressive strengths (2 d and 28 d), and an open porosity test was performed. The obtained results were verified by printing tests. In addition, an economic and environmental life cycle assessment (LCA) of the mixes was performed. The results indicate that up to 50 vol% cement replacement with fRA is feasible, albeit with some technical drawbacks. While fRA incorporation enhances sustainability by reducing CO2 emissions and material costs, it adversely affects the printability window, green strength, setting time, and mechanical properties, particularly in the initial curing stages. Therefore, with higher replacement rates (above 20 vol%), potential optimization efforts are needed to mitigate drawbacks such as reduced green strength and buildability. Notably, replacement rates of up to 20 vol% can be successfully used without compromising the overall material properties or altering the mixture design. The LCA analysis shows that reducing the cement content and increasing the fRA addition results in a significant reduction in mix cost (up to 24%) and a substantial decrease in equivalent CO2 emissions (up to 48%). In conclusion, this study underscores the potential of fRA as a sustainable alternative to cement in 3D printed concrete.

Supported Ionic Liquid-Phase Materials (SILP) as a Multifunctional Group of Highly Stable Modifiers and Hardeners for Carbon and Flax Epoxy Composites.

This paper introduces a novel approach to enhance epoxy resin formulations by using SILP materials as multifunctional hardeners and fillers in composite structures reinforced with carbon and flax fibers. This study explores the integration of ionic liquids (ILs) onto a silica support structure, presenting various permutations involving silica selection, ionic liquid choice, and concentration. The focus of this study was to elucidate the influence of SILP on resin curing ability and the mechanical properties of the resulting composites. Detailed research was conducted, including Brunauer-Emmett-Teller analysis (BET) for SILP materials and curing characterization for epoxy resin formulations with different SILP materials. Furthermore, the mechanical properties of the obtained composites were determined by Scanning Electron Microscopy analysis (SEM) (the force at break, the maximum elongation at break, tensile strength, and modulus of elasticity). Through SILP incorporation, the mechanical properties of composites, including the modulus of elasticity and tensile strength, are substantially improved, a phenomenon akin to traditional filler effects. The findings highlight SILP materials as prospective candidates for concurrent hardening and filling roles within composites (through a single-step procedure, with prolonged storage stability and controlled processing conditions), particularly pertinent as the composite industry veers toward epoxy bioresins necessitating liquefaction via temperature application.

Evaluation of fracture resistance of radicular dentin treated with nanochitosan-loaded calcium hydroxide and nanographene-loaded calcium hydroxide, when used as intracanal medicament: An in vitro study

ABSTRACT Aim: This study aimed to evaluate and compare the effect of using calcium hydroxide (CH) loaded with nanochitosan and nanographene on radicular dentin fracture resistance. Methods: A total of 40 mandibular premolar root canals were instrumented with the ProTaper rotary system. The fracture resistance of radicular dentin was measured with the universal testing machine, following which intracanal medicament was placed for 10 days. CH alone and CH mixed with nanoparticles of chitosan and graphene were used. Not using any intracanal medicament was used as the control. A one-way ANOVA, followed by the post hoc Tukey’s test, was used to compare the results of different groups. Results: The highest mean for the force at compressive stress was seen in the control group, and the least was recorded by CH. Intergroup comparison for Young’s modulus showed a statistically significant difference (P < 0.05) between the control group and CH (P = 0.002); CH and chitosan + CH (P = 0.003) on post hoc analysis. Conclusion: Incorporation of chitosan and graphene nanoparticles in CH when used as intracanal medicament improves the modulus of elasticity and compressive strength of radicular dentin, which in turn improves dentin elasticity and fracture toughness when compared to CH alone.

Mechanical performance degradation investigation on FRP reinforced concrete based on neural network design method

To predict the effect of chemical-freezing coupling erosion on the properties of four kinds of FRP-reinforced concrete. Rapid freeze–thaw tests were conducted. The mass loss rate, relative dynamic elastic modulus, compressive strength, and flexural capacity were tested to investigate the Mechanical Performance of specimens. The compression specimens are cylindrical specimens wrapped with FRP, and the flexural specimens are pasted with FRP prismatic specimens on the pre-cracked side. A database was built based on 45 groups of experimental test results, and the prediction effect of the BP neural network and CNN model on compressive strength and flexural capacity was compared, respectively. The results showed that CNN did a better job. Finally, the maximum number of freeze–thaw cycles of different FRP-reinforced specimens was predicted based on the CNN model with mass loss rate and relative dynamic modulus as the evaluation criteria. This method can provide a new perspective for predicting the durability of FRP-reinforced concrete.

Dual Ion Regulated Eutectogels with High Elasticity and Adhesive Strength for Accurate Strain Sensors

AbstractEutectogels have attracted increasing attention from researchers due to their broad application potential, good environmental stability, biocompatibility, and low cost. Currently reported eutectogels generally show large residue strain and hysteresis, which will cause output signal inconsistency between the loading and unloading processes and is not conducive to accurate strain monitoring. Besides, the low adhesiveness of available eutectogels brings about difficulties in the installation of the sensors and dynamic interfacial stability between the sensors and human skin. Herein, a dual ion regulation strategy is proposed to obtain eutectogels with high resilience, high adhesiveness, ultralow residue strain, wide temperature adaptability (−20–60 °C) and good environmental stability. Strain sensors based on gradient eutectogels exhibit high sensitivity, a wide linear response range, and good cycling stability. The response curve shows negligible electrical hysteresis, providing consistent output signals at the fixed strain regardless of stretch or release. Accurate micrometry with a step as minute as 50 µm is realized. Moreover, the sensors demonstrate higher signal intensity and stability in human physiological signals and motion detection due to the strong interfacial bonding.

Investigation of punching shear performance in concrete slabs reinforced with GFRP and synthetic fibers: An experimental study

The punching shear resistance mechanism of reinforced concrete slabs with glass fiber-reinforced polymers (GFRP-RC) is weaker than that of steel-RC slabs. The reduced shear strength and modulus of elasticity of GFRP reinforcement which led to greater tensile strains of the reinforcement and shallower compressive zone reduce the contribution of concrete in compression, aggregate interlocking, and dowel action to the punching shear mechanism. This condition results in reduced capacity and a higher likelihood of catastrophic failure compared to their steel-RC counterparts. To address this weakness of GFRP-RC, this paper aims to examine the punching shear performance of GFRP-RC slabs and explore the potential improvements through the incorporation of synthetic fibers. A total of 11 two-way slabs having a dimension of 1000 × 1000 mm with a thickness of 80 mm were tested under punching shear load and the effect of several types of fiber (polypropylene (PP) and (polyvinyl alcohol (PVA)), fiber content (0, 0.5%), reinforcement ratio, and reinforcement type (steel and GFRP) was investigated. The slabs’ behavior was assessed by considering crack width, deflection performance, the mode of failure, and the overall load-bearing capacity. The findings indicated that the influence of fibers was more noticeable in GFRP-RC slabs compared with steel-RC counterparts. Moreover, the fibers were found to effectively reduce deflections and crack widths. The results particularly showed the superior performance of PVA fibers in improving the capacity of the two-way slabs, whereby the addition of 0.5% PVA fibers led to the punching shear capacity increase of 44–51%. The findings of this study offer a better understanding of the punching shear behavior of slabs reinforced with GFRP reinforcement and synthetic fibers.

The Effects of Different Beverages on Fracture Resistance of CAD/CAM Monolithic PEEK and Monolithic Zirconia Crowns

Aim: To assess the impact of various beverages on the fracture resistance of CAD/CAM polyetheretherketone (PEEK) and monolithic zirconia materials. Materials and Method: We fabricated eighty CAD/CAM materials from PEEK polymer (CopraPeek; Whitepeaks Dental Solutions GmbH, Germany) and monolithic zirconia (inCoris TZI; Dentsply Sirona Systems GmbH, Bensheim, Germany), with ten samples per group. These samples were submerged in either distilled water, cola, coffee, or red wine and stored at 37°C for 12 days. We utilized a universal testing machine (Lloyd LRX; Lloyd Instruments Ltd., West Sussex, UK) to measure each sample’s fracture resistance. The t-test provided a comparison of normally distributed variables between the two groups. For multiple group comparisons, we executed an analysis of variance (ANOVA). Results: A statistically significant difference was observed between the PEEK and zirconia groups in terms of maximum load and elastic load-bearing capacity values (p˂0.05), with zirconia materials yielding higher values. However, there was no critical difference in these measures obtained from different solutions for neither PEEK nor zirconia samples (p>0.05). Conclusion: CAD/CAM monolithic PEEK material stored in various solutions demonstrated lower fracture resistance and elastic strength than monolithic zirconia materials. Despite this, PEEK exhibited the highest fracture resistance to intraoral occlusal forces. Accordingly, due to its chemically inert nature and superior force absorption, we recommend PEEK as a viable alternative material for posterior crowns in fixed restorations.