Thermomechanical Characteristics Research Articles

Experimental Study of Thermomechanical Characteristics of C/ARMC Composites at High Temperatures as Thermal Protection Systems for Aerospace Applications

Experimental Study of Thermomechanical Characteristics of C/ARMC Composites at High Temperatures as Thermal Protection Systems for Aerospace Applications

Thermite frass biomass and surface modified biowaste coir fiber reinforced biocomposites-Conversion of waste to useful products.

Polymer composites are known for its light weight and specific mechanical characteristics. This study examines sodium hydroxide (NaOH)-treated coir fiber, an agro-leftover, stuffed in a polyester matrix with termite frass powder, a bio-leftover for possible use in light-weight structural applications. Composite samples were made using compression molding and NaOH-treated coir fiber reinforced hybrid polymer composite (TCRHPC) with 40 wt% treated coir fiber and 1, 2, 3, and 4 wt% termite frass powder. TCRHPC samples mechanical, water captivation, tribological, and thermal properties were affected by termite frass powder wt%. The TCRHPC sample with 3 wt% termite frass powder has excellent mechanical properties, which improved by tensile (41.6%), flexural (28.57%), impact (43.7%), and hardness (18.84%) properties. With perfect water captivation and low weight increases in normal water (0.017 g), seawater (0.015 g), and NaOH solution (0.010 g), the identical composite sample with thermal stability up to 238°C also reduced wear mass by 5.27%. Conversely, filler agglomeration and heterogeneous dispersion in composite sample impair thermo-mechanical characteristics of TCRHPC containing 4 wt% termite frass powder. The bonding among polyester, treated coir fiber, and termite frass powder in composites were appraised with the aid of fractographic images of TCRHPC samples. The results show that TCRHPC material suits well for support structures requiring lesser weight.

Thermo-Mechanical Properties of Particulate Banana Epoxy Composite with Fruit Waste (Dragon Fruit Peel) Micro Filler for Household Applications

This study evaluates the thermo-mechanical characteristics of eco-friendly composite made of particulate banana fiber (reinforcement), epoxy resin (matrix) and dragon fruit peel powder (micro filler). The composites were developed using compression moulding technique with 3 factors, 4 variations and Taguchi orthogonal array design (L16). The proposed filler characterization results revealed that the density was 0.97 g/cm3 and combination of C–O, Ca–O, and Ca–Co could improve mechanical strength. Composites with 5 mm fiber length, 40 wt.% fiber weight, and 15 wt.% filler weight have a maximum tensile strength of 25.58 MPa, flexural strength of 44.47 MPa, impact strength 180.33 J/m, and hardness of 82.50 SD. The best composite’s thermal, wear, water and fatigue studies were proposed to suit household applications. The proposed filler improves fiber-resin bonding, which increases thermal stability to 245 °C, wear resistance, decreases water absorption, and results in a fatigue life count of 121000 cycles. Thus, this study concluded that the increasing filler content and decreasing particulate size had an impact on the thermo-mechanical characteristics of banana-reinforced polymeric composites. As a result, an eco-friendly polymeric composite mixer coupler model was developed. Comparative structural and model analyses were performed using ANSYS R17.2. The analysis results confirmed that the proposed composite had higher natural frequencies of 2766.5 Hz and lower deformation values of 0.089293 mm. This proves the proposed eco-friendly composite is a suitable replacement for a synthetic mixer coupler.

Growth of nano-porous covalent organic frameworks on graphenic carbon hollow spheres; towards designing advanced multi-functional nanocomposites

For the first time, melamine-based covalent organic frameworks (COFs) were synthesized in situ on the graphenic shells of carbon hollow spheres (CHSs) for achieving a hybrid nanomaterial with unique thermo-mechanical characteristics. To improve the thermal stability of CHS-COF nanostructures (NSs), Zn2+/sodium L-glutamate (ZG) inorganic-organic complexes were loaded in their porosities and interior spaces (denoted as ZG@CHS-COF). The fabricated epoxy nanocomposites illustrated enhanced thermo-mechanical and UV-shielding properties. The tensile strength of the epoxy coatings, filled with CHS-COF and ZG@CHS-COF NSs, increased by 185 and 168 %, respectively, compared to the blank epoxy. DMTA results revealed that the glass transition temperature (Tg) of the epoxy, filled with CHS-COF and ZG@CHS-COF NSs increased around 2.1 and 8.1 °C, respectively. Also, the lower height of tan(δ) peaks (HTP) in the presence of CHS-COF and ZG@CHS-COF NSs illustrated their better interactions with epoxy chains. The highest ash content (≈46.3 %) and superior thermal durability were acquired in the presence of ZG@CHS-COF NSs. TEM results confirmed the better dispersion and distribution of ZG@CHS-COF NSs than CHS ones. The ZG@CHS-COF-filled epoxy coating led to a 71 % reduction in color changes (ΔE) after 3 weeks of UV irradiation.

Size-dependent thermomechanical vibration characteristics of rotating pre-twisted functionally graded shear deformable microbeams

Size-dependent thermomechanical vibration characteristics of rotating pre-twisted functionally graded shear deformable microbeams

Molecular Dynamics Investigations of Thermomechanical Characteristics of Solid and Hollow Spherical Platinum Nanoparticles during Additive Manufacturing

Molecular Dynamics Investigations of Thermomechanical Characteristics of Solid and Hollow Spherical Platinum Nanoparticles during Additive Manufacturing

Thermo-mechanical characteristics of spent coffee grounds reinforced bio-composites

Abstract This research examines the incorporation of spent coffee grounds (SCGs) into composite materials utilizing a three-part system composed of modified castor oil, polyester resin, and SCGs. The objective is to assess the mechanical, microstructural, and thermal characteristics of the resultant composites. The composite specimens underwent a thorough preparation and were tested through a battery of procedures comprising tensile testing, shore D hardness testing, SEM, FT-IR, and thermal conductivity measurements. Tensile testing revealed higher mechanical resilience, reinforcing the desirable properties of SCGs. The 5 % SCG-reinforced sample exhibited the highest tensile strength value, with a 41.85 % increase observed in comparison to the pure sample. The results of shore D hardness tests demonstrated that there was no significant change in material hardness up to 3 % additive content. However, a decrease in hardness was observed at higher additive rates. At a 7 % additive rate, there was a 2.82 % decrease in material hardness. Furthermore, the application of scanning electron microscopy (SEM) analysis has revealed the microstructural features of the composite matrix, which have highlighted the distribution of SCGs within it. The successful implementation of SCGs has also been verified by means of Fourier transform infrared (FT-IR) analysis. Finally, based on thermal conductivity measurements, it has been determined that SCGs are suitable for thermal insulation purposes. This study represents a significant contribution to the field of sustainable materials science, emphasising the potential benefits of SCGs in improving the effectiveness of composite materials.

Mechanical and piezoresistive performance of additively manufactured carbon fiber/PA12 hybrid honeycombs

This study investigates a novel self-sensing honeycomb composite structure composed of two distinct cellular layers with differing unit cell architectures, specifically hexagonal and re-entrant designs. Short carbon fiber (CF)/polyamide 12 (PA12) composite filaments with 0, 5 or 15 wt.% CF content were utilized to additively manufacture the honeycomb structures via Fused Filament Fabrication (FFF), and their mechanical and piezoresistive self-sensing characteristics were experimentally investigated under quasi-static in-plane and out-of-plane compression at both room temperature and elevated temperatures. The results reveal that the hybrid hexagonal/re-entrant (HR) honeycombs mechanically outperform their non-hybrid double-layer and single-layer counterparts under in-plane loading, reporting an increase in collapse strength and energy absorption by factors of 1.64 and 2.25, respectively. These improvements are attributed to the mechanical interactions occurring at the interface between the auxetic and non-auxetic layers within the hybrid structure, effectively enhancing its structural attributes. Furthermore, the double-layer honeycombs display excellent strain-sensing capabilities within the elastic regime, with gauge factors reaching values as high as 146. Mechanical tests conducted at elevated temperatures reveal that the CF/PA12 honeycombs retain a significant portion of their elastic modulus, strength and energy absorption even at 125 °C, while maintaining high gauge factors of up to 72.4. These honeycombs also exhibit pronounced thermoresistive behavior, evidenced by a decrease in electrical resistance of up to 41.3 % with increasing temperatures from 25 to 125 °C. Considering their exceptional combination of thermo-mechanical, thermoresistive and piezoresistive characteristics, these hybrid double-layered CF/PA12 honeycombs hold promise for potential applications in multifunctional lightweight structures, offering integrated temperature and strain-sensing capabilities.

CO2 separation performance and thermo-mechanical characteristics of mixed matrix membranes composed of polyvinylidene fluoride/hyperbranched polyethylenimine embedded with zinc oxide/graphene oxide filler

CO2 separation performance and thermo-mechanical characteristics of mixed matrix membranes composed of polyvinylidene fluoride/hyperbranched polyethylenimine embedded with zinc oxide/graphene oxide filler

Electrospun nanostructured heparin conjugated-poly-ε-caprolactone based scaffold promote differentiation of smooth muscle cells from adipose mesenchymal stem cells

BackgroundTissue engineering integrating cell-based approaches is promising for urinary tract injury treatments. PurposeExploring the Impact of Nanostructured Heparin Conjugated-Polycaprolactone (HPCL) on the differentiation of Adipose Mesenchymal Stem Cells (ADMSCs) into Smooth Muscle Cells (SMCs). MethodsPCL nanofibers were produced by electrospinning and conjugated with heparin. The surface properties of the scaffolds were analyzed using FE-SEM for imaging, FTIR for investigation of chemical structure, assessments of surface roughness, thermomechanical characteristics, and the contact angle to evaluate wettability. The study included six groups; Group I: ADMSCs cells, Group II: ADMSCs seeded on PCL, Group III: ADMSCs seeded on HPCL, Group IV: SMCs cells, Group V: SMCs seeded on PCL, and Group VI: MSCs seeded on HPCL. SMCs differentiation was evaluated using specific genes and proteins. ResultsImmobilization of heparin was confirmed by amide I (3427 cm−1) and it was significantly raised on HPCL scaffolds. SMCs + HPCL group revealed the highest cell viability and the most significant increase in differentiation-related genes and proteins at 7 days (p < 0.05). ConclusionHPCL nanofibers have an effect on SMCs differentiation, which are the functional units of the ureter. Therefore, they could represent a valuable tool for tissue engineering applications in ureter repair.

A Critical Review on Recent Advancements in Aluminium-Based Metal Matrix Composites

Aluminum matrix composites (AMCs) have garnered significant attention across various industrial sectors owing to their remarkable properties compared to conventional engineering materials. These include low density, high strength-to-weight ratio, excellent corrosion resistance, enhanced wear resistance, and favorable high-temperature properties. These materials find extensive applications in the military, automotive, and aerospace industries. AMCs are manufactured using diverse processing techniques, tailored to their specific classifications. Over three decades of intensive research have yielded numerous scientific revelations regarding the internal and extrinsic influences of ceramic reinforcement on the mechanical, thermomechanical, tribological, and physical characteristics of AMCs. In recent times, AMCs have witnessed a surge in usage across high-tech structural and functional domains, encompassing sports and recreation, automotive, aerospace, defense, and thermal management applications. Notably, studies on particle-reinforced cast AMCs originated in India during the 1970s, attained industrial maturity in developed nations, and are now progressively penetrating the mainstream materials arena. This study provides a comprehensive understanding of AMC material systems, encompassing processing, microstructure, characteristics, and applications, with the latest advancements in the field.

Coupled responses of thermomechanical waves in functionally graded viscoelastic nanobeams via thermoelastic heat conduction model including Atangana–Baleanu fractional derivative

Accurately characterizing the thermomechanical parameters of nanoscale systems is essential for understanding their performance and building innovative nanoscale technologies due to their distinct behaviours. Fractional thermal transport models are commonly utilized to correctly depict the heat transfer that occurs in these nanoscale systems. The current study presents a novel mathematical thermoelastic model that incorporates a new fractional differential constitutive equation for heat conduction. This heat equation is useful for understanding the effects of thermal memory. An application of a fractional-time Atangana–Baleanu (AB) derivative with a local and non-singular kernel was utilized in the process of developing the mathematical model that was suggested. To deal with effects that depend on size, nonlocal constitutive relations are introduced. Furthermore, in order to take into consideration, the viscoelastic behaviour of the material at the nanoscale, the fractional Kelvin–Voigt model is utilized. The proposed model is highly effective in properly depicting the unusual thermal conductivity phenomena often found in nanoscale devices. The study also considered the mechanical deformation, temperature variations, and viscoelastic characteristics of the functionally graded (FG) nanostructured beams. The consideration was made that the material characteristics exhibit heterogeneity and continuous variation across the thickness of the beam as the nanobeam transitions from a ceramic composition in the lower region to a metallic composition in the upper region. The complicated thermomechanical features of simply supported viscoelastic nanobeams that were exposed to harmonic heat flow were determined by the application of the model that was constructed. Heterogeneity, nonlocality, and fractional operators are some of the important variables that contribute to its success, and this article provides a full study and illustration of the significance of these characteristics. The results that were obtained have the potential to play a significant role in pushing forward the design and development of tools, materials, and nanostructures that have viscoelastic mechanical characteristics and graded functions.

Sol-gel derived silicate-phosphate glass SiO2–P2O5–CaO–TiO2: The effect of titanium isopropoxide on porosity and thermomechanical stability

Despite of several decades lasting extensive research of bioactive and bioresorbable glasses the systematic parametrization and determination of the key factors affecting porosity and thermomechanical characteristics still remains challenging. Here, we present silica-phosphate glasses, with the composition 70SiO2–20P2O5–(10-x)CaO–xTiO2 (mol%; x = 0, 2.5, 5, and 7.5), prepared by sol-gel method and reinforced by titanium dioxide via titanium isopropoxide (TTIP) incorporation which demonstrated tunable variation of porosity from micro-to macro-region and superb mechanical integrity during the calcination process. The presence of 7.5 mol% TiO2 promotes dimensional stability up to 1000 °C as investigated by thermomechanical analysis. The XRD showed the dominant presence of silicon phosphate [Si(P2O7)], titanium phosphate [Ti(P2O7)] and calcium phosphates [β-Ca(P2O6) and γ- Ca2(P2O7)]. The effect of TiO2 doping on the multiscale morphology and porosity was investigated by means of SEM, MIP, μCT, N2 adsorption and USAXS/SAXS. Increasing TiO2 content leads to the formation of open porosity up to 70 vol% and drives the formation of a refined interconnected macroporosity of 2–30 μm. In contrast, mesoporosity with a dominance of 3–6 nm pores decreases in all samples with increasing TiO2 content. USAXS/SAXS revealed an increase in primary particle size with increasing TiO2 content which is in good agreement with the nitrogen physisorption analysis showing that microporosity decreases with increasing TiO2 content.

ВИЗНАЧЕННЯ ТЕХНОЛОГІЧНИХ ПАРАМЕТРІВ ЛАЗЕРНОГО ВИПРОМІНЕННЯ ДЛЯ ОТРИМАННЯ СУБМІКРО- ТА НАНОСТРУКТУР У ЗМІЦНЮВАЛЬНИХ ПОКРИТТЯХ НА СТАЛЯХ

Using the previously developed model of theoretical processes in the zone of laser irradiation, where thermal and thermomechanical processes are described, including the influence of crystallization energy and other internal energies during the formation of nanostructures at various temperature levels, further investigation of the thermal and thermomechanical characteristics of different structural steels during the formation of nanostructures on their surfaces using laser irradiation was conducted. To validate the model, temperature fields were determined in the zone of laser irradiation on steel 20 (Fig. 1a) and steel 50 (Fig. 1b), considering both heating and cooling processes. Calculations were performed for heat flux densities and durations of exposure close to those necessary for obtaining nanostructures (500...2000 K) and with temperature rise rates exceeding 10^7 K/s. As a result of calculations using the refined thermal model, temperature distributions at a depth of 1 μm during laser irradiation on steel with different carbon contents (steel 20, 38Х, 50, and У8) at various peak heat flux densities in the surface layer were obtained. A spatiotemporal distribution of temperatures along the radius of the laser spot and over time during laser irradiation with a heat flux density of q=3∙10^8 W/m^2 at a spot radius of 0.1 mm was constructed. Zones of nanostructure formation were identified depending on the heat flux density over the duration of laser irradiation. Theoretical investigations using the updated thermal model confirmed the need to consider the temperature rise rate, as exceeding it increases the likelihood of thermomechanical failure. At the same time, due to insufficient temperature rise rates during laser nanostructure formation in the surface layers of carbon steels, more micro- and sub microstructures are formed.

Online Detection of Laser Welding Penetration Depth Based on Multi-Sensor Features.

The accurate online detection of laser welding penetration depth has been a critical problem to which the industry has paid the most attention. Aiming at the laser welding process of TC4 titanium alloy, a multi-sensor monitoring system that obtained the keyhole/molten pool images and laser-induced plasma spectrum was built. The influences of laser power on the keyhole/molten pool morphologies and plasma thermo-mechanical characteristics were investigated. The results showed that there were significant correlations among the variations of the keyhole-molten pool, plasma spectrum, and penetration depth. The image features and spectral features were extracted by image processing and dimension-reduction methods, respectively. Moreover, several penetration depth prediction models based on single-sensor features and multi-sensor features were established. The mean square error of the neural network model built by multi-sensor features was 0.0162, which was smaller than that of the model built by single-sensor features. The established high-precision model provided a theoretical basis for real-time feedback control of the penetration depth in the laser welding process.

Green Bionanocomposites of Poly(Lactic Acid) (PLA) and Linear Low-Density Polyethylene (LLDPE): Fabrication and Properties

This study utilizes a polymer matrix made from a combination of Poly (Lactic Acid) (PLA) and Linear Low-Density Polyethylene (LLDPE). The polymer matrix is then improved by adding a compatibilizer, Polyethylene-graft-maleic anhydride (PE-g-MA), a filler, Recycled Tyre Waste (RTW), and a nano-scale filler, Graphene nanoplatelets (GNPs). Examining how PE-g-MA, RTW, and GNPs influence the binary blend's (PLA/RTW) chemical and thermo-mechanical characteristics is the focus of this study. A twin-screw extruder is used for the melting and intercalating processes. The binary mixture consists of 5% PE-g-MA, five percent RTW, and 3% GNPs. The samples are then pelletized after being cooled to room temperature. Analysis and characterization of the pelletized samples thermal and chemical characteristics follow. After including a compatibilizer, filler, and nanofiller into the bionanocomposite, improved qualities are anticipated.

Nonlinear dynamic response of a temperature-dependent FGM spherical shell under various boundary conditions and thermal shocks: Examination of dynamic snap-through

In this study, a comprehensive exploration of the nonlinear dynamic snap-through phenomenon observed in shallow spherical shells composed of functionally graded materials (FGMs) is examined. The analysis encompasses the interplay of thermomechanical characteristics within metal and ceramic phases, taking into account their temperature-dependent behaviors. To address this problem, the transient heat conduction equation in a nonlinear form, accounting for the temperature dependence factor is derived. To solve this complexity, the Generalized Differential Quadrature (GDQ) method is employed, coupled with the Crank-Nicolson time integrating scheme, leveraging an iterative approach for precision. The formulation of nonlinear dynamic motion equations is based on Hamilton's principle and incorporates the utilization of nonlinear strain-displacement equations and uncoupled thermoelasticity. In the spatial domain, GDQ proves invaluable in solving these nonlinear, coupled equations. In the temporal domain, the Newmark procedure in conjunction with the Newton-Raphson iterative method are utilized to navigate through dynamic equations, yielding insights into shell's behavior over time. In the initial stages of the investigation, we validate our spherical shell formulation and methodologies by comparing shell's response with existing, simpler works. This step ensures the reliability and accuracy of our model. The primary objective is to assess the presence and characteristics of the thermal snap-through phenomenon within the shell under these diverse conditions.

An investigation on damage tolerant design parameter of additively manufactured Al 2024: Fatigue crack growth rate and fracture toughness

Additive manufacturing has emerged as a key forefront of the fourth industrial revolution due to its exceptional design freedom and ability to produce lightweight components for different structural applications. However, the unique thermomechanical characteristics of these additive processes introduce several challenges to the structural integrity and the corresponding life of these components. The structural components, specifically in the aerospace industry, are usually designed according to the damage tolerance approach. The Al 2024 alloy is one of the most widely used alloy in structural applications in the aerospace industry due to its high strength-to-weight ratio and excellent fatigue properties. However, studies on the FCGR behaviour of additively manufactured Al 2024 are scarce in the literature; hence, the current study investigates the FCGR behaviour under stress-controlled loading using a stress ratio of 0.2 and 0.3. The aged specimen showed superior mechanical properties compared to the as-printed specimen, and the properties of the T6 aged specimen are comparable to their wrought counterparts. The different precipitate–dislocation interaction is investigated and correlated with corresponding mechanical behaviour. The primary strengthening mechanism in Al 2024 alloy was observed to be the Orowan bypass mechanism in θ(Al2Cu), and S(Al2CuMg) precipitate.

Evaluation of orange peel (Citrus sinensis) bioplastic through morphological and thermo-mechanical characteristics.

Objective: To evaluate the morphological and thermo-mechanical properties of a biofilm obtained from orange peel.&#x0D; Design/methodology/approach: Pectin, a polysaccharide obtained from orange peel, has the potential to be used as a raw material in the bioplastics industry. The samples obtained were characterized by the Scanning Electron Microscopy (SEM) technique, mechanical tension and by thermogravimetric analysis (TGA).&#x0D; Results: The elastic modulus was in the range of 7.7 to 29.9 MPa, depending on the plasticizer content. The thermogravimetric analysis showed a thermal decomposition between 134.42 to 153.98 °C depending on the plasticizer content and up to five events were identified.&#x0D; Limitations of the study/implications: During the process, a pectin yield of 75% of orange peel was obtained.&#x0D; Findings/conclusions: In developing countries such as Mexico, waste originating from agricultural and agro-industrial activities represents an important source of natural carbohydrate polymers that can be used to produce bioplastics, intended to replace petroleum-derived materials. In the case of orange peel, it can become a potential raw material to obtain value-added products in sectors of the food industry. These results indicated that our pectin has suitable properties to be used as raw material for the manufacture of bioplastics.

Mechanical and Thermomechanical Characteristics of the Ni50Ti47.5Hf2.5 Alloy with a High-Temperature Shape Memory Effect

Mechanical and Thermomechanical Characteristics of the Ni50Ti47.5Hf2.5 Alloy with a High-Temperature Shape Memory Effect