Specific Compressive Strength Research Articles

Meta-structure of amorphous-inspired 65.1Co28.2Cr5.3Mo lattices augmented by artificial intelligence

A hatching-distance-controlled lattice of 65.1Co28.2Cr5.3Mo is additively manufactured via laser powder bed fusion with a couple of periodic and aperiodic arrangements of nodes and struts. Thus, the proposed lattice has an amorphous-inspired structure in the short- and long-range orders. From the structural perspective, an artificial intelligence algorithm is used to effectively align lattices with various hatching distances. Then, the metastable lattice combination exhibits an unexpectedly high specific compression strength that is only slightly below that of a solid structure. From the microstructural perspective, the nodes in the newly designed lattice, where the thermal energy from laser irradiation is mainly concentrated, exhibit an equiaxial microstructure. By contrast, the struts exhibit a columnar microstructure, thereby allowing the thermal energy to pass through the narrow ligaments. The heterogeneous phase differences between the nodal and strut areas explain the strength-deteriorating mechanism, owing to the undesirable multi-phase development in the as-built state. However, solid-solution heat treatment to form a homogeneous phase bestows even higher specific compression strength. Furthermore, electrochemical leaching leads to the formation of nanovesicles on the surface of the microporous lattice system, thereby leading to a large surface area. A more advanced valve cage for use in a power plant is designed by using artificial intelligence both to (i) effectively preserve its mechanical stiffness and (ii) actively dissipate the generated stress through the large surface area provided by the nanovesicles.

THE EFFECT OF CEMENT KILN DUST ON THE PROPERTIES OF CEMENT

Due to the nature of the technological process, the cement industry is a significant source of dust. Managing industrial waste is a global problem worldwide; cement kiln dust is an example of such waste. The dust from the cement kiln is a by-product of the cement production process obtained during the grinding and burning of the raw materials inside the cement kiln. Still, due to its high alkaline content, it cannot be returned to the kiln, but its disposal and landfill can cause many environmental problems. It is necessary to find alternative methods for its utilization. Due to its fineness and composition like that of cement, there is a growing interest in the use of this powder as a partial substitute for ordinary Portland cement. The purpose of this paper is to investigate the influence of dust obtained during the production of cement clinker on the properties of cement (specific surface area, standard consistency, setting time, and compressive strength) and its implications in the conditions of its application.

Sunflower pith inspired dual-gradient cellular polyurethane architecture with amplified mechanical functions

Artificial cellular materials with various mechanical functions are attracting increasing attentions from aerospace, transportation, and industrialization. However, many artificial cellular materials, despite of the hierarchically ordered structures and even unique performance to some, still lag behind many natural ones in amplification of mechanical functions owing to the limitations in intrinsic mechanical performance and sophisticated structural design. Herein, inspired with lightweight and high strength of sunflower piths, we proposed a dual-gradient structure consisting of pore size gradient and wall thickness gradient to engineer cellular architectures with desirable mechanical performance by harnessing vat photopolymerization 3D printing of double crosslinking networks polyurethane elastomer. The double-gradient cellular polyurethane architecture displays more exceptional capability in load-bearing and energy absorption compared with non– and single gradient structures. Besides, the specific compressive strength and energy absorption of the dual-gradient cellular architectures are 4 times higher than those of traditional mechanical metamaterial structures such as octet-truss lattice, gyroid lattice, and porous structure prepared with the same material. Potential mechanisms such as dual-gradient cellular structures to obtain selective flexural deformation behaviour increasing their energy absorption and dissipation capacity are fully elucidated. As the potential paradigms, we demonstrated the mechanical functions of biomimetic mechanical cellular architectures for efficient impact protection and noise isolation, which offered a promising perspective toward developing soft metamaterials with excellent mechanical functions for potential soft machines and engineering applications.

Preparation and Characterization of Lightweight Carbon Foam Derived From Silicon‐Containing Arylacetylene Resin With Antioxidant Properties and Excellent Electromagnetic Interference Shielding Performance

ABSTRACTIn this study, carbon foam derived from silicon‐containing arylacetylene resin (CFPSA) was prepared by using silicon‐containing arylacetylene (PSA) resin as the carbon precursor and polyurethane (PU) foam as the organic sacrificial template. CFPSAs with diverse apparent densities were prepared through the simple impregnation of PU foam with PSA resin solutions of varying concentrations. Their structures, such as the pore morphology; chemical composition; thermal stability; compression properties, and electromagnetic interference (EMI) shielding effectiveness (SE), were characterized. The results indicate that with an increase in the PSA resin concentration, the skeleton of CFPSA becomes thicker, the pore size slightly increases, the apparent density increases, the compressive strength increases, and the EMI SE slightly reduces. CFPSA‐10's apparent density is 0.032 g/cm3, its 5% thermal weight loss temperature (Td5) in an air atmosphere is 642°C, its thermal conductivity is 38.1 mW/m K, its specific compression strength is 2.45 MPa/g cm3, and its specific EMI SE divided by thickness (SSE/t) is 2367 dB cm2/g. CFPSA exhibits lightweight and antioxidant properties, as well as excellent electromagnetic interference shielding performance, presenting great potential for application in aerospace and other fields.

Compressive Strength Analysis of Additively Manufactured Zirconia Honeycomb Sandwich Ceramic Parts with Different Cellular Structures

In this study, ZrO2 honeycomb sandwich structures with different cellular geometry were manufactured by SLA 3D-printing technology to analyze the compressive strength behaviour. After the printing procedure, the samples were sintered at 1450 °C for 2h. Among the samples with different cellular geometry, ZrO2 parts with circular cells were superior to that of square and triangular honeycomb structures and 1867±320 MPa compressive strength was obtained for this structure. The stress distributions in honeycomb structures were investigated using the COMSOL Multiphysics® for exposing the effect of cellular geometry on compressive strength. While more uniform stress distributions were seen on the inner wall of the circular honeycomb sample, the cellular structure of the square and triangle honeycomb samples mostly displayed compressive stress concentration on the joints of the honeycomb structure. Also, according to Rankine failure criterion, the parts with square cellular geometries were found to be more prone to failure. The highest specific compressive strength was obtained for the ZrO2 parts with circular cellular geometry. These findings demonstrated that the ZrO2 honeycomb sandwich structures with circular cellular geometry produced using SLA ceramic 3D-printing technology may be a suitable material to utilize in lightweight structural designs.

Ceramic/metal composites fabricated via 3D printing and ultrasonic-assisted infiltration for high specific strength and energy absorption

To address the strength-toughness dilemma, ceramic/metal interpenetrating phase composites (IPCs), fabricated through metal infiltration into ceramic perform, have been investigated. However, infiltrating metal into porous ceramic scaffold with high volume fraction remains a significant challenge. Herein, we propose a novel method to fabricate highly dense Al2O3/AlSi10Mg (Al) interpenetrating phase composites through ultrasonic-assisted pressureless infiltration into 3D printed ceramic scaffolds. Experimental results indicate that the as-fabricated Al2O3/Al IPCs exhibit excellent quasi-static and dynamic mechanical properties. Specifically, the materials can achieve high specific compressive strengths of 148.6 ± 5.2 MPa/(g/cm3) under quasi-static compression and 228.6 ± 4.5 MPa/(g/cm3) under dynamic compression while also exhibiting high specific energy absorption of 33.6 ± 0.9 J/g under quasi-static compression and 37.7 ± 1.1 J/g under dynamic compression. The specific compressive strength and specific energy absorption of the as-fabricated Al2O3/Al IPCs outperform those of the literature-reported ceramic/metal IPCs. This work provides an innovative approach to fabricate strong and tough ceramic composites.

Spark plasma sintering of cenosphere-derived Cs/Sr-aluminosilicates for 137Cs and 90Sr immobilization in mineral-like ceramics

In this study, a promising method of spark plasma sintering (SPS) was investigated for the fabrication of ceramic matrices designed for the reliable immobilization of highly radioactive radionuclides 137Cs and 90Sr. The ceramic matrices were derived from a mixed composition of two aluminosilicate mineral-like phases – pollucite (Cs,Na)AlSi2O6 and gehlenite Sr2Al2SiO7. The originality of the developed approach lies in the utilization of hydrothermal synthesis for obtaining granulated precursor material. Hollow aluminosilicate microspheres (cenospheres) from coal fly ash served as the initial raw material, which were treated with alkaline solutions containing Cs+ and Sr2+ ions as simulants for the corresponding radionuclides. This method facilitated the achievement of high efficiency in cation removal from solutions exceeding 98 %. For a comprehensive examination of the composition and morphology of cenosphere-derived precursor particles, and the influence of sintering temperature on phase and structure formation of ceramic matrices under non-equilibrium conditions of spark plasma heating, various analytical techniques were employed. These included thermogravimetry/differential thermal analysis (TG/DTA), powdered X-ray diffraction analysis (PXRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), as well as the method of low-temperature nitrogen adsorption for determining the specific surface area. The obtained ceramic samples exhibited high values of specific density (2.688–2.915 g/cm³), compressive strength (666–808 MPa), and Vickers microhardness (1.8–2.5 GPa), attesting to their high quality and stability. The results of the hydrolytic stability assessment revealed that the leaching rates of Cs+ and Sr2+ ions from the ceramics are extremely low, within the range of 10−5–10−6 g/cm²·day. These values fully satisfy the requirements of GOST R 50926–96 and the international standard ISO 6961:1982 for solidified forms of high-level waste.

Bending Collapse and Energy Absorption of Dual-Phase Lattice Structures.

A dual-phase lattice structure composed of mixed units with hard and soft phase characteristics is proposed in this work. The proposed lattice structure has high specific energy absorption and high compressive strength. The load response and energy absorption characteristics under bending loads were studied through three-point bending tests and numerical analysis methods. The research results indicate that although the deformation modes of the given lattice structure are the same, the dual-phase design strategy significantly improves the bending performance of the lattice structure: the bending modulus is increased by 744.7%, and the specific energy absorption is increased by 243.5%.

Achieving Remarkable Specific Mechanical Strength and Energy Absorption Capacity in SiC Nanowire Networks through Graded Structural Design.

Lightweight porous ceramics with a unique combination of superior mechanical strength and damage tolerance are in significant demand in many fields such as energy absorption, aerospace vehicles, and chemical engineering; however, it is difficult to meet these mechanical requirements with conventional porous ceramics. Here, we report a graded structure design strategy to fabricate porous ceramic nanowire networks that simultaneously possess excellent mechanical strength and energy absorption capacity. Our optimized graded nanowire networks show a compressive strength of up to 35.6 MPa at a low density of 540 mg·cm-3, giving rise to a high specific compressive strength of 65.7 kN·m·kg-1 and a high energy absorption capacity of 17.1 kJ·kg-1, owing to a homogeneous distribution of stress upon loading. These values are top performance compared to other porous ceramics, giving our materials significant potential in various engineering fields.

Enhanced molding and mechanical properties of SiC-based ceramic lattice structures via digital light processing

Silicon carbide (SiC) ceramic lattice structures (CLSs) hold significant potential for use in structural components and optical mirrors in space exploration due to their light weight, high strength, and excellent dimensional stability. However, they face challenges such as poor curing performance and weak mechanical strength during the digital light processing (DLP) additive manufacturing process. In this study, SiC@Al2O3 powder was prepared, resulting in a 21% reduction in absorptivity compared to bare SiC powder. The ceramic paste derived from this powder achieved a curing thickness of up to 80 μm, exhibited a reduced over-curing width, and demonstrated a 75% improvement in stability compared to bare SiC paste. Consequently, high-quality triply periodic minimal surfaces (TMPS) structured SiC@Al2O3 CLSs green bodies were successfully fabricated. By integrating precursor impregnation pyrolysis with the reaction melting infiltration (PIP-RMI) post-treatment densification method, SiC@Al2O3/Si CLSs were produced, exhibiting superior mechanical properties with low dimensional shrinkage. At 30% volume fraction, the specific compressive strength of the primitive-TPMS SiC@Al2O3/Si CLSs reached 24.79 MPa. This study presents an effective method for fabricating SiC-based ceramic CLSs and establishes a foundation for the optimization of SiC ceramic fabrication processes.

An inspection of the metal-foam beam considering torsional dynamic responses

Metal foam is a multifunctional material with a lower specific weight, high stiffness and compressive strength, and high energy absorption. These remarkable properties make metal foams a promising candidate for conventional materials in different industrial fields. Despite numerous researches on mechanical behavior either static or dynamic of structures made of metal foams, torsional vibration analysis of metal foam structures is still uninvestigated. In this investigation, the influence of various imperfection distribution patterns on the torsional dynamic response of metal foam beams is examined within the framework of Timoshenko-Gere's theory. Two common materials i.e. SUS304 and Aluminum foams are considered the constructive materials of structure. Moreover, three imperfection distribution patterns are taken into account. The virtual work's principle has been employed to derive the torsional governing equation of metal foam beams. Then, the derived governing equation has been solved via an analytical method. The accuracy of the employed methodology has been compared with the findings of former research in the literature. Finally, the influences of different notable parameters on the variation of natural torsional frequency have been examined and demonstrated in a group of tables and diagrams.

2D/2D coupled MOF/Fe composite metamaterials enable robust ultra–broadband microwave absorption

The combination between macroscopic structure designs and microscopic material designs offers tremendous possibilities for the development of advanced electromagnetic wave (EMW) absorbers. Herein, we propose a metamaterial design to address persistent challenges in this field, including narrow bandwidth, low–frequency bottlenecks, and, particularly, the urgent issue of robustness (i.e., oblique, and polarized incidence). Our absorber features a semiconductive metal-organic framework/iron 2D/2D assembly (CuHT–FCIP) with abundant crystal/crystal heterojunctions and strong magneto-electric coupling networks. This design achieves remarkable EMW absorption across a broad range (2 to 40 GHz) at a thickness of just 9.3 mm. Notably, it maintains stable performance against oblique incidence (within 75°) and polarizations (both transverse electric and transverse magnetic). Furthermore, the absorber demonstrates high specific compressive strength (201.01 MPa·cm3·g−1) and low density (0.89 g·cm−3). This advancement holds promise for developing robust EMW absorbers with superior performance.

Mix design determination procedure for geopolymer concrete based on target strength method

This study presents the development and validation of a mix design determination procedure for geopolymer concrete to achieve the desired compressive strength. The procedure integrates artificial neural network (ANN) model developed based on a comprehensive data base from literature, data clustering, and parameter optimization techniques to enhance accuracy and reliability. Experimental validation is undertaken to demonstrate the mix design determination procedure’s capability to accurately predict mix designs for geopolymer concrete based on the target compressive strength, validating its efficacy for mix proportion determination. The integration of chemical oxide content in fly ash, curing time, curing temperature, and activator properties results in a 15.9% improvement in prediction accuracy for the training dataset and a 68.3% enhancement for the testing dataset, compared to the base ANN model that includes only the weight of fly ash and activator properties. Employing data clustering techniques enables the identification of prior estimates for the mix design parameters related to specific fly ash types and target compressive strength, streamlining the mix design process by analyzing pertinent data subsets. Parameter optimization ensures refined mix proportions, achieving the desired target strength economically while minimizing material waste and cost. The development of a user interface facilitates easy manipulation of mix designs, catering to users of varying expertise levels. Additional options for deeper insights into geopolymer concrete characteristics can be integrated into the mix design determination procedure. To assess the mix design determination procedure's ability to generalize effectively, a variety of fly ash samples with distinct chemical compositions were utilized, differing from those already present in the database. This approach allows for a thorough evaluation of the mix design determination procedure's performance when presented with fly ash compositions it has not encountered before. By doing so, this provides insights into the adaptability of the mix design determination procedure beyond the limitations of the training and testing datasets.

Mechanical properties and failure behavior of additively manufactured Al2O3 lattice structures infiltrated with phenol-formaldehyde resin

The lightweight design and load-bearing capacity of underwater vehicles remain perennial focal points. Ceramic lattice structures (CLSs) offer significant weight reduction while maximizing structural strength; however, their inherent brittleness poses a limitation. To optimize the performance of CLSs for underwater vehicle applications, a biomimetic Al2O3/phenol-formaldehyde (PF) resin composite structure (APCS) was proposed and fabricated by infiltrating additive-manufactured Al2O3 lattice structures (ALSs) with PF. Comprehensive assessments of the quasi-static mechanical properties were conducted using both experimental and simulation methods. The specific compressive strength and specific energy absorption of the APCSs under quasi-static compressive loading exhibited remarkable improvements, with the maximum values achieved from the body-centered cubic (BCC)/PF structure increasing by ∼15.23 and ∼307.93 times, respectively. In contrast to ALSs, the failure process of APCSs was gradual, with the confining pressure introduced by the PF promoting transverse crack propagation and layer-by-layer failure, thereby strengthening the ceramic lattice. Toughing mechanisms (i.e., crack arrest, crack deflection, and branching) were also observed in the APCSs. Furthermore, the simulation results aligned well with the experimental results, providing an in-depth analysis of internal damage and crack propagation. The improvements introduced by the composite structure in this study provide a reliable approach for obtaining lightweight and strong materials, thereby accelerating the application of ceramic-based materials in underwater vehicles.

Revitalization Of Balango: Local Ceramic Art and Products from Galogandang Luhak Nan Tuo, West Sumatra

Balango, a traditional pottery used as a cooking utensil in Minangkabau villages, has been transformed as an interior aesthetic support or aesthetic element, so that balango becomes more dynamic and has prospects as an art commodity. This research aims to examine the revitalization of pottery at Galogandang Pottery Hall in Luhan Nan Tuo, West Sumatra. This research uses a mixed method as a reference strategy for developing the potential of clay for the application of local pottery crafts in a sustainable manner through a creative approach supported by laboratory tests. Balango at Galogandang Pottery Hall, there is a development of local art product designs in the form of flower vases; pendil teapots, and kadhai whose clay raw materials are formulated from three types of soil with a clay fraction of 23% (sandy loam clay); kaolinite (21%), illite (41%), and quartz (38) minerals; oxide composition dominated by SiO2 (37%) and Fe2O3 (35%); burn shrinkage (19%); specific gravity (1.75 g cm-3), porosity (26.60%) and compressive strength (225.48 kg cm-2). This composition can be used to customize new ideas for other products by combining different forms (figurative and abstract), resulting in visually beautiful and functional utilitarian pottery for interiors with artistic quality and local flavor.

The Chinese Knot inspired anisotropic TC4 lattice Structures: Ultra-high specific strength in engineering materials

Lattice structures possess high specific strength, multi-functionality through innovative structural designs. Here, we proposed an efficient method for the construction of lattice structures by elongating two-dimensional planar patterns along the load direction, which enabled the efficient utilization of 100 % materials for load bearing. Inspired by Chinese Knot (CK), a series of meticulously crafted TC4 lattice structures were fabricated by using selective laser melting. These structures feature nine tubular units arranged in a 3 × 3 matrix interconnected by sixteen parallel plates, and their failure modes were subsequently investigated by uniaxial compression tests. The results show that the specific compressive strength of the CK structure enhances as increasing the density. The detachment between the plate and tube, and the buckling of the plate, lead to the premature failure, which in turn leads to substantial variations in strength, estimated at approximately 80 MPa at ∼ 1.5 g/cm3. When the thickness of the plate exceeds 0.5 mm, and the tube wall thickness exceeds 0.04 mm, the CK structures show high stability and exhibit a 45° shear failure mode. Notably, the specific strength of the CK structure can surpass 330 MPa∙cm3/g, which represents the peak level of specific compressive strength compared to the current TC4 lattice structures.

Aerogel honeycombs with orientation-induced microstructures for high-temperature lightweight composite sandwich structures

Lightweight honeycomb structures are widely used in applications that require high strength-to-weight ratios and low densities, including aircraft, automobiles, and various engine components. However, due to the immaturity of microstructure conditioning techniques and the fact that highly porous structures usually fracture during stretching, it is challenging to obtain both high-strength and lightweight porous structures. Herein, a newly developed multilayer interconnected polyimide aerogel-based paper honeycomb is successfully prepared based on the ice crystal reverse template method and multi-level structure regulation via chemical and physical interactions. The synergistic effect of the hot extrusion-stress strategy and the heat imidization process provides the submicron layer of the paper honeycomb wall with more orderly molecular chain stacking, excellent orientation, and an enhanced folding degree between layers. The prepared polyimide aerogel paper honeycombs have low density (approx. 8–9 kg/m3), good shear strength of 1.07 MPa (W direction) and 0.86 MPa (L direction), excellent specific compressive strength (0.38 MPa), and excellent thermal stability. These integrally molded polyimide paper honeycombs, as sandwich resin-based composite structures, provide a new versatile platform for aerospace and marine applications.

Buckling resistance of ultra-low-density carbon fiber curved-wall honeycomb based on stretching process

Although honeycomb is a kind of lightweight structural material with great potential, its specific strength is not always able to meet the requirements, especially in the weight-sensitive field. Inspired by the bionic idea of cuttlebone, the curved-wall configuration design is proposed to strengthen the buckling impedance of honeycomb, which can effectively prevent the premature occurrence of buckling failure mode induced by thin walls. Compared with the straight-wall honeycomb materials of the same geometric size, the probability of buckling failure in curved-wall honeycomb materials proposed in this paper is reduced by more than 22 %. Moreover, to achieve the preparation of curved-wall configuration, a processing strategy that uses stretching process to prepare ultralight carbon fiber honeycomb (Carbcomb) material is firstly introduced. Compared to the Hexcel Corporation’s aluminum honeycomb with a density of 21 kg/m3, for the Carbcomb, the specific compressive strength and specific shear strength along both the L and W directions respectively improved by 57 %, 61 % and 77 %. In addition, the minimum density of fabricated Carbcomb (14.6 kg/m3) is less than that of the Hexcel's products (16 kg/m3), and the research findings fill the gap of the carbon fiber honeycomb material in low density areas (10 ∼ 30 kg/m3). More importantly, this process which does not require much manual operation can effectively avoid the problems of unstable mechanical properties, difficult mass production and high preparation cost of the existing carbon fiber structural parts. This curved-wall configuration design and fabricated approach widens the potential of carbon fiber honeycomb as a structural material, and makes it possible for lower cost and higher efficiency in aerospace and transportation applications.

Topological optimisation and laser additive manufacturing of force-direction-sensitive NiTi porous structures with large deformation recovery behaviour

ABSTRACT Optimising the cell type and configuration is a key approach for overcoming stress concentration and irreversible deformation in lightweight lattice structures with high strength. In this work, the topology optimisation method was utilised to design force-direction-sensitive structures, including face-centre loaded (FCL), central-edge loaded (CEL), and hybrid-loaded (HL) structures, which were manufactured by laser powder bed fusion (LPBF) using Nitinol (NiTi) shape memory alloy. Results indicated that the HL lattice exhibited the highest initial peak force of 7.6 kN with higher specific compressive strength (41.74 MPa·cm3/g) and specific energy absorption (6.82 J/g), which was benefit from the layer-by-layer deformation mechanism. Furthermore, the HL lattice also exhibited the best damping properties and energy absorption capacity, while achieving a high shape recovery ratio of 85%. This work offers insights into a design strategy for functional structures with high strength and large deformation recovery capacity.

SiOC foam‐aerogel composites: Optimal balance of lightness and excellent thermal insulation

AbstractFoam‐aerogel composites are synthesized in polymeric, hybrid, and ceramic states by completing the open cells of the foam with a solution forming a wet gel, carbon dioxide (CO2) supercritically dried, and pyrolyzed. Thermal diffusivity measurements are conducted using the laser flash, and for mechanical performance, cold crushing tests are done to obtain compressive strengths. Samples possess a range of specific surface area (SSA) values up to ∼650 m2/g contingent upon the material state, that is, polymeric, hybrid, or ceramic. While SSA values can be deliberately altered, almost all samples demonstrated a total porosity of ∼90 vol%, with superb specific compressive strength reaching around 2 MPa. In addition to adjustable surface characteristics granting hydrophobic and hydrophilic features, the study revealed the potential use of these foam‐aerogel composites as thermal insulators with low thermal conductivities of 0.02 W·m−1·K−1 at RT and 0.05 W·m−1·K−1 at 500°C. When exposed directly to a butane flame gun with a flame temperature reaching ∼1200°C, from the backside of a 5 mm‐thick foam‐aerogel composite, only ∼200°C is recorded, which is lower than a comparable commercial insulator panel tested under the same conditions.