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Steel slag powder-cement composite mortar (SSP-cement mortar), a low-carbon building material with industrial solid waste can effectively utilize SSP. However, the low hydration activity of SSP has a significant adverse effect on its early-age behavior. In this study, the early-age compressive behavior and stress–strain relationship of a high-strength SSP-cement mortar at the first curing period of 7 days were comprehensively studied. The mix proportion parameters include the replacement ratio of SSP Rs, cement strength grade fce, mesh of SSP ν, and water-binder ratio W/B. The curing temperature was set at T = 20℃ and T = 80℃. The results indicate that: firstly, at T = 20℃ and T = 80℃, the optimal values for cube compressive strength fcu are 71.2 MPa and 112.4 MPa, respectively, axial compressive strength fc are 50.1 MPa and 85.4 MPa, respectively. Secondly, with the increase of Rs, the fc, elastic modulus Ec, and toughness U, showed decreasing trends, the peak strain εcp shows an increasing trend. The trends have weakened at T = 80 ℃. With the increase of fce and ν, all the indexes (fc, εcp, Ec, and U) show an upward trend. With the increase of W/B, all the indexes show a decreasing trend and are more pronounced at T = 20℃. Finally, an early compressive stress–strain relationship of SSP-cement mortar was established. Based on the given parameters and curing temperatures, a compressive strength prediction model is provided to guide engineering applications. [ABSTRACT FROM AUTHOR]

AbstractHoneycomb materials are considered ultra-light materials with excellent mechanical properties due to their unique cellular structure. Their high strength, low density, and excellent energy-absorbing abilities have led to their widespread application in various fields. The star cellular structure is a classical cellular structure proposed by many scholars, exhibiting a negative Poisson’s ratio effect. However, due to the susceptibility of the star-shaped units and the vertical supporting rods at the joints to local instability and stress concentration under compressive loads, the buckling of the supporting rods can induce lateral displacement, thereby compromising the overall structural integrity and performance. To address this phenomenon, this study eliminates the supporting rods from the star-shaped structure, specimens of the Improved Star-Shaped Honeycomb (ISSH) were fabricated using Selective Laser Sintering (SLS) technology, followed by uniaxial quasi-static compression experiments and finite element simulations, followed by uniaxial quasi-static compression experiments and finite element simulations. The study investigates whether changes in geometric parameters can enhance the tunability of the structure for different application scenarios. The results reveal that the rod-free star-shaped structure exhibits higher stiffness and strength, and variations in wall thickness and angular parameters significantly influence the structural performance and deformation failure mechanisms. This study enriches the research on star-shaped honeycomb structures. [ABSTRACT FROM AUTHOR]

This study investigates the use of cotton ropes (CRs) as a sustainable and cost-effective substitute for synthetic fiber-reinforced polymers for concrete confinement, offering significant environmental benefits such as lower CO2 emissions and reduced energy consumption. The work evaluates the effectiveness of CR strips for confining concrete, including scenarios with recycled concrete aggregates (ReCA). Compressive strength improvements varied among specimens, with Specimen I-3F showing a 140.52% increase and Specimen II-3F achieving a 46.67% improvement. Strip configurations for Type I recycled aggregate concrete (RAC) outperformed full wraps on Type II RAC, exemplified by Specimen I-3S's 84.51% improvement. Ultimate strain enhancements ranged from 915% to 4490.91%, driven by the significant rupture strain of cotton rope confinement. For Type I RAC, complete wrapping significantly outperformed strip configurations by 56%, 50%, and 32% in ultimate strength improvement for 1, 2, and 3 layers, respectively. The confinement ratio, varying from 0.10 to 0.70, greatly influenced the compressive behavior, with compressive strength normalized by unconfined strength increasing consistently with the confinement ratio. A minimum confinement ratio of roughly 0.40 is required to achieve an increasing second part in the compressive behavior. The initial parabolic branch was modeled using Popovics' formulation, revealing an elastic modulus approximately 20% lower than ACI 318-19 predictions. The second branch was described using a linear approximation, and nonlinear regression analysis produced expressions for key points on the idealized compressive curve, enhancing model accuracy for CR-confined RAC. The R 2 values for the nonlinear regression analysis performed on experimental results were greater than 0.90. This study highlights the effectiveness of neural network expressions to predict the compressive strength of CR-confined concrete. A strength reduction (ratio of full wrap and strip wrap height CRs) factor of 0.67 was proposed and used for strip-wrapped specimens. It was seen that the neural network models also predicted the compressive strength of partially wrapped specimens with reasonable accuracy using the strength reduction factor. [ABSTRACT FROM AUTHOR]

This research examines the effect of biochar and recycled gypsum drywall (RGD) on the mechanical properties and microstructure of conventional and high-volume fly ash concrete (HVFC) by testing 60 cylinders. Results suggested that although adding biochar increased the porosity of concrete, its effect on concrete's properties relied on its porosity, pore interconnectivity, and water retention capacity, plus characteristics of binders. The biochar-retained water (BRW) accelerated the hydration of C3S, increasing the dosage of calcium carbonate and calcium aluminate silicate hydrate on the top of biochar pores. The accelerated hydration enhanced early-age strength. Besides the hydration acceleration of OPC, BRW primarily promoted the RGD reactions and fly ash activation in HVFC. Nonetheless, the high porosity, inertness, and potential deterioration of biochar weakened the concrete in the long term and lowered its elastic modulus. Biochar also boosted ductile behavior, especially in HVFC with RGD, and lowered the carbon footprint of the concrete. [ABSTRACT FROM AUTHOR]

The lattice structure is a periodically repeating three-dimensional open-cell architecture, and the introduction of polymer materials into its gaps results in a lattice structure filled with silicone rubber that can simultaneously exhibit vibration reduction, energy absorption, and other functional characteristics. In this study, the compressive behavior of both the lattice structure and the lattice structure filled with silicone rubber were investigated through a combination of finite element analysis and experimental investigations. The results show that the finite element analysis results are consistent with the experimental ones, and the method can be used to analyze such structures. Lattice structures filled with silicone rubber have better load-bearing capacity compared to lattice structures, and the integration of silicone rubber increases the compressive strength of the lattice structure, reducing the occurrence of structural localization phenomena. [ABSTRACT FROM AUTHOR]

Mechanical metamaterials as a category of lightweight materials have exhibited superior specific mechanical properties and energy absorption. However, lack of reasonable structural design always results in weakening or failure to achieve the optimal mechanical performance of metamaterials. Here, we firstly adopted bio-inspired and structural optimization methods to guideline the design of microlattice structures. Inspired by the strong and ductile 'Moso' bamboo, three bamboo-inspired hierarchical microlattice structures (BHMSs) were initially designed, and the bamboo's features, viz., hollow, gradient distribution, and cellular, were imitated by designed BHMSs. Optimization design with the objective of maximum ratio of strain energy and reaction force was carried out to furthermore improve the mechanical properties of BHMSs. Afterwards, the optimal BHMSs were printed via Stereolithography. The compressive responses of BHMSs were elaborated by experiments and simulation. Results show that these designed biomimetic structures can be easily tailored via tuning the geometric sizes of unit cell, achieving high compressive specific modulus and strength 48.16 kPa m3 kg−1 and 1389.23 Pa m3 kg−1 and the energy-absorbing efficient 85.43% in the octet bamboo-inspired hierarchical microlattice structures (OCT BHMSs). The design strategies and findings shed light on the realization of advanced metamaterials with tailored mechanical properties. How to design ordered cellular structures for lightweight structures with high mechanical strength and energy absorption efficiency remains a crucial challenge in automation, aerospace and lightweight construction fields. Inspired by the lightweight and high load-bearing capacity of nature bamboos and metamaterials in the previous researches (Song et al., Materials & Design, 2019, 173: 107773; Song et al., International Journal of Fatigue, 2017, 100: 126), here a comprehensive approach of bionics and optimization was proposed to design hierarchical microlattice structures with lightweight, good mechanical properties and high energy absorption efficiency. The bamboo's characteristics, including hollow, gradient enhancement, and cellular, were completely copied to reasonably produce hierarchical microlattice configurations, while the optimal sizes were obtained though the optimization design. Highlights: A combination strategy of bamboo-inspired and optimization design to realize light-weight and high mechanical metamaterials was provided. Mechanical properties of biomimetic structures can be tailored by tuning dimensions based on optimization. A high energy absorption efficiency in octet-truss bamboo-inspired hierarchical microlattice structures. [ABSTRACT FROM AUTHOR]

Manufacturing technology has been refined and described for the fabrication of honeycomb-based bioresorbable networks for temporal bone replacement applications. Two novel techniques, digital light processing and investment casting, were utilized to produce customized, shape-optimized cellular constructs with additional orifices promoting tissue ingrowth during osteo-regeneration. For this purpose, a conventional magnesium casting alloy (AZ91) was chosen. Numerical simulations were conducted to predict the compressive behavior of the proposed biodegradable lightweight scaffolds. Spatial castings were adjusted to possess mechanical properties comparable to the ones of cortical or trabecular bones. Two kinds of protective coatings (plasma electrolytic oxidation and organic ones based on natural polyphenols from tea extract) were deposited and characterized. They can be utilized to control the degradation rate during exploitation to achieve a predictable implant lifespan. The elaborated layers aim to mitigate the rapid corrosion of magnesium substrates by prolonging their bioresorption time and thus expanding their applicability in osseointegration. To evaluate this assumption, immersion tests in phosphate-buffered saline were performed, showing better chemical resistance of PEO coating and as-cast sample (for both mass gain by below 1%), and visible increase in mass of sample coated with organic coating (increase by almost 5%). Compressive strength results from numerical approach were further validated by experimental compression tests, showing that PEO coating deteriorated compressive strength by almost 3%, and organic coating improved it by over 9%. Results achieved in numerical approach were better than expected for stiffer sample, and slightly lower for the one with bigger pores. [ABSTRACT FROM AUTHOR]

The external hydraulic pressure and internal medium pressure acting on submarine pipelines can lead to the coupling effect of active and passive constraints on the mechanical performance of steel–concrete double-skin composite tubes, resulting in a significantly different bearing capacity mechanism compared to terrestrial engineering. In this paper, the full-range concentric compressive mechanism of new-type stainless steel–concrete double-skin (SSCDS) composite tubes subjected to dual hydraulic pressure was analyzed by the finite element method. The influence of geometric–physical parameters at various water depths was discussed. The key results reveal that imposing dual hydraulic pressures significantly improves the confinement of double-skin tubes to encased concrete, resulting in a higher axial compressive strength and a non-uniform stress distribution; increasing the material strengths of concrete, outer tubes and inner tubes results in an approximately linear enhancement in axial bearing capacity; enhancing the diameter-to-thickness ratios of outer tubes and inner tubes can decrease the bearing capacity of SSCDS composite tubes; and the axial compression strength of SSCDS composite tubes with a higher hollow ratio of 0.849 tends to decrease with increasing outer hydraulic pressure. A practical method that integrates the effects of dual hydraulic pressures was developed and validated for the strength calculation of SSCDS composite tubes. This research provides fundamental guidelines for the application of pipe-in-pipe structures in deep-sea engineering. [ABSTRACT FROM AUTHOR]

The utilization of 3D printing technology has transformed the possibilities for design adaptability and manufacturability. This study delves into the mechanical response and energy absorptivity of resin‐based lattice structures when subjected to compression, specifically examining structures fabricated from Tough 2000 (ductile) and Rigid 10K (brittle) resin materials using a stereolithography 3D printer. The analysis encompasses various types of lattice designs (such as cubic‐primitive, circular, triangular, and hexagonal), gradient structures, and combined shape configurations with varying strut dimensions. The primary objective is to provide significant findings regarding the compressive performance of these resin lattice structures produced through 3D printing. Analysis results show that graded and combined lattice designs have better compressive behavior compared to regular shapes with the same strut thickness. In addition, and for strut thickness of 0.5 mm, combined lattice designs show better energy absorption capabilities compared to regular shapes. [ABSTRACT FROM AUTHOR]

Abstract The use of bio-based biomass construction materials has the advantage of helping to reduce fossil energy demand, protecting the environment from carbon dioxide emission and reducing the production of non-degradable waste. This paper used resin-modified soy protein (SP) adhesive to combine rice straw stalks, and made straw-soy protein composites (SSPC) material. The physical properties, compressive behavior and stability during wetting drying cycles of SSPC were measured. Due to water evaporation, the SP matrix is full of connected pores, resulting to its physical properties of small density, high shrinkage ratio and low thermal conductivity, which are 0.24 g/cm3, 16.2%, and 0.065 W/(m•K), respectively. Adding straw is helpful to the physical properties of SP matrix, leading to an obvious decrease in shrinkage ratio and thermal conductivity of SSPC, which are 8.51% and 0.075 W/m•K. Furthermore, the compressive load–displacement curves of SSPC groups divide into two types: divergent and convergent. The compressive strength of divergent samples is decided by the critical displacement determined according to the convergent specimens. It shows that straw stalk proves the positive effect on the compressive property of SP matrix. As to the mass of SSPC samples during the wetting drying cycles, it drops apparently in the initial three cycles, and becomes negligible from the fifth cycle, meaning that the stability of SSPC during wetting drying cyclic process is quite good. The research result would be helpful for using SSPC as building material, especially as thermal insulation material.

Waste rock backfilled into a goaf can function as the main load-bearing carrier to support the overlying strata, so the compressive behavior of backfill materials plays a critical role in the effectiveness of strata control. However, in the laboratory, the specimen size also significantly influences on the accurate prediction of compressive deformation in waste rock backfill materials. To assess the influence of the specimen size on compressive behavior in waste rock backfill materials, a WAW-1000D (Changchun Xinte Testing Machine Co., Ltd., Changchun, Jilin Province, China) electric servo-motor testing machine and self-made compressors of different sizes were used to characterize the compressive deformation of waste rock backfill materials with different specimen sizes. The stress–strain relationships and changes in the void ratio of specimens were analyzed, revealing the influence of the specimen size on the compressive behavior. The research found that when the ratio of the inner diameter of compressors to the maximum particle size of specimens is 15:1 and above, the inner diameter of compressors only has a slight influence. Taking a backfill panel in Xinjulong Coal Mine as the engineering context, waste rock with particle sizes in the range of 0~20 mm was backfilled. The measured roof subsidence was 568 mm, matching the measured experimental value. The results provide data to support roof subsidence predictions following waste rock backfill mining. [ABSTRACT FROM AUTHOR]

The mechanical behavior of the metallic components fabricated by additive manufacturing (AM) technologies can be influenced by adjustments in their microstructure or by using specially engineered geometries. Manipulating the topological features of the component, such as incorporating unit cells, enables the production of lighter metamaterials, such as lattice structures. This study investigates the mechanical behavior of lattice structures created from AlSi10Mg, which were produced using the laser beam powder bed fusion (LB-PBF) process. Specifically, their behavior under pure compressive loading has been numerically and experimentally investigated using ten different configurations. Experimental methods and finite element analysis (FEA) were used to investigate the behavior of body-centered cubic (BCC) lattice structures, specifically examining the effects of tapering the struts by varying their diameters at the endpoints ( d end ) and midpoints ( d mid ), as well as altering the height of the joint nodes (h). The unit cells were designed with varying parameters in such a way that d end is changed at three levels, while d mid and h are changed at two levels. Significant differences in Young's modulus, yield strength, and ultimate compressive strength between the various specimen configurations were observed both experimentally and numerically. The FEA underestimated the Young's modulus corresponding to the configurations with thinner struts in comparison to the higher values found experimentally. Conversely, the FEA overestimated the Young's modulus of those configurations with larger strut diameters with respect to the experimentally determined values. Additionally, the proposed FE method consistently underestimated the yield strength relative to the experimental values, with notable discrepancies in specific configurations. [ABSTRACT FROM AUTHOR]

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Raw coal gangue (RCG) as one of the solid wastes can result in serious ecological and environmental pollution. Utilization of RCG as coarse aggregates in concrete can mitigate the demand for natural aggregates in engineering construction to a certain extent. This study aims to assess the impact of utilizing raw coal gangue aggregates (RCGAs) on the mechanical behaviors and compressive stress–strain responses of concrete. For this purpose, a total of 90 concrete specimens were prepared, varying in RCGA replacement ratios of 0, 30%, 50%, 70%, and 100% and water‐to‐cement (w/c) ratios of 0.37 and 0.47. The slump, compressive and splitting tensile strengths in cubes, and complete compressive stress–strain curves of RCGA concrete were obtained and discussed. Results indicated that as RCGA was incorporated, the peak stress and elastic modulus of concretes with 0.37 and 0.47 w/c ratios decreased by 26%–51% and 23%–57%, respectively. In addition, the crack development and microstructural characteristics of RCGA concrete were analyzed by digital image correlation and scanning electron microscopy (SEM), respectively. The SEM analysis indicated that the interface transition zone between RCGAs and mortar was relatively thick and loose compared to that between coarse natural aggregates and mortar, indicating the poor mechanical properties of RCGA concrete. Finally, based on the test data, a normalized stress–strain model for RCGA concrete was proposed, taking into account the influence of RCGA replacement. [ABSTRACT FROM AUTHOR]

Microcapsule-based self-healing concrete (MSC) has been widely studied, with a focus on static behavior and self-healing effectiveness. However, the dynamic mechanical properties of MSC have rarely been studied. This study presents a mesoscale numerical investigation of the dynamic compressive behavior of MSC under impact loading. In mesoscale, MSC is regarded as a four-phase composite material mainly composed of coarse aggregates, interface transition zones, cement mortar, and microcapsules. A pseudo 3D numerical model is constructed by combining a slice of a detailed mesoscale model with a homogenous 3D model. The mesoscale MSC slice models with different mass fractions of microcapsules (0%, 2%, 5%, and 8%) are constructed. Different coarse aggregate shapes (i.e., circles, ellipses, and polygons) are considered. The uniaxial dynamic compressive behaviors of MSC materials under loads of different strain rates are numerically simulated and compared with those from split Hopkinson pressure bar tests previously done by the authors. The comparison results show that the present mesoscale model can accurately predict the compressive strength and failure mode of MSC. The effects of the microcapsules ratio and strain rate on the dynamic strength are studied. Results show that the MSC compressive strength decreases with the increase in microcapsules and increases with the increase in strain rate. The dynamic increase factor (DIF) of the specimen is jointly contributed by the material DIF, inertial constraints, and heterogeneity. Different aggregate shapes have little effect on the simulation results of MSC behavior. The obtained dynamic mechanical properties of MSC may assist in designing MSC to resist collisions or explosions. [ABSTRACT FROM AUTHOR]

Abstract The utilization of 3D printing technology has transformed the possibilities for design adaptability and manufacturability. This study delves into the mechanical response and energy absorptivity of resin‐based lattice structures when subjected to compression, specifically examining structures fabricated from Tough 2000 (ductile) and Rigid 10K (brittle) resin materials using a stereolithography 3D printer. The analysis encompasses various types of lattice designs (such as cubic‐primitive, circular, triangular, and hexagonal), gradient structures, and combined shape configurations with varying strut dimensions. The primary objective is to provide significant findings regarding the compressive performance of these resin lattice structures produced through 3D printing. Analysis results show that graded and combined lattice designs have better compressive behavior compared to regular shapes with the same strut thickness. In addition, and for strut thickness of 0.5 mm, combined lattice designs show better energy absorption capabilities compared to regular shapes.

By simulating the hydrothermal solidification technique of underground rock formation mechanism, the sludge soil is dehydrated and mixed evenly with lime, recycled aggregates, etc., and then pressed into bricks. The bricks are then cured under high temperature and high pressure in an autoclave to undergo hydrothermal solidification reaction inside, forming green and environmentally friendly hydrothermal solidified slag soil bricks. To study the basic mechanical properties of hydrothermal solidified slag soil brick masonry, hydrothermal solidified slag soil brick masonry was designed and fabricated, and axial compressive tests were conducted to investigate the effects of brick type, mortar type, and strength on the failure process, load deformation characteristics, compressive strength, and elastic modulus of the masonry. The results showed that the compressive strength design value and average elastic modulus of hydrothermal solidified slag soil brick were 38% and 44% higher than the requirements of GB 50003--2011, respectively. This product can be used to replace traditional wall materials in practical engineering applications. [ABSTRACT FROM AUTHOR]

Due to the behavior of low-density and high-energy absorption efficiency, rubber materials are now being extensively applied to solve geotechnical problems. In order to ensure the rational and economical use of rubber sand mixtures in geotechnical engineering, it is necessary to systematically study the compression behavior of rubber sand mixtures, especially under repeated loading–unloading mode. In this study, three series tests, including one-dimensional compression tests and repeated loading–unloading tests, were conducted on rubber sand mixtures with various rubber contents. The development of the void ratio, compression coefficient, elastic strain, and plastic strain of the mixtures under different load modes was investigated. Results showed that compared to pure sand, rubber sand mixtures exhibited different compression deformation behavior. The rubber content had a significant impact on the compression behavior of rubber sand mixtures. The compression behavior of the rubber sand mixture changed from low to high compressibility when the rubber content was greater than 10%. Also, with the increase of rubber content from 0% to 20%, the ratio between elastic and plastic strain of the mixtures increased from 1∶5 to 2∶3. When subjected to loading and unloading cycles within a large stress range (0–1,600 kPa), the rubber sand mixture underwent significant elastic strain, and plastic strain gradually accumulated with the number of cycles. When the repeated loading and unloading test started at a certain initial pressure (800–1,600 kPa), the elastic deformation of the rubber sand mixture decreased to a smaller level and did not change significantly with the number of cycles. At this point, plastic strain mainly occurred in the first cycle, and almost no plastic strain occurred in subsequent cycles. Rubber content below 10% has lower compressibility and is a recommended rubber content (RC) value for use in engineering. In addition, setting a certain initial pressure is an effective method to reduce the elastic strain of mixtures and improve the accumulation of plastic strain in engineering applications. [ABSTRACT FROM AUTHOR]

Hybrid double-skin tubular columns (DSTCs), which consist of an outer fiber-reinforced polymer (FRP) tube, an inner steel tube, and a concrete annular layer between the two tubes, possess many advantages, such as high load resistance and large deformation capacity and excellent durability. The use of ultrahigh-performance concrete (UHPC) or engineered cementitious composites (ECCs) instead of normal strength concrete (NSC) in the annular layer, given the advantages such as the ultrahigh strength of UHPC and strain hardening and high toughness feature of ECC, endows the DSTCs with additional high performance, such as an enhanced load-carrying capacity (with UHPC) and an improved cracking resistance (with ECC). The behavior of such DSTC specimens with UHPC or ECC that are subjected to eccentric loading was investigated for the first time, to the best of the authors' knowledge, and the results are reported in this paper. The DSTC specimens with NSC and ECC under eccentric compression exhibited similar great ductility with a bilinear shape for the axial load–deformation curves. In addition, the initial cracking of the FRP tube at the tension side of DSTC specimens with ECC or NSC occurred later than that of DSTC specimens with UHPC, which might imply the better durability performance of DSTC specimens with ECC or NSC during the serviceability state. [ABSTRACT FROM AUTHOR]

In this study, topological optimization techniques were employed to construct innovative TopS lattice structures, to achieve a lightweight design while simultaneously optimizing their mechanical properties and enhancing flow and heat transfer performance. Through model reconstruction and proportional scaling techniques, lightweight configurations with increased surface areas were achieved, leading to the successful fabrication of Ti-6Al-4V lattice structures via Laser Powder Bed Fusion (LPBF) technology. A comprehensive investigation combining numerical simulations and experimental testing revealed that the TopS-L16 lattice structure outperforms TopS-L1 and TopS-L4 in terms of compressive strength, demonstrating values of 386.00 MPa for compressive strength, 352.00 MPa for upper compressive yield strength, and 6938.00 MPa for elastic modulus. Furthermore, multilayer-filled lattice structures were found to effectively improve streamline distribution and vorticity, reducing boundary layers, which indicates a significant enhancement in fluid flow and heat transfer performance, with TopS-L16 exhibiting the best performance. The novelty of this work lies in its exploration of the interplay between lattice structures and their interactions with compressive deformation, energy absorption capabilities, and flow heat transfer.

Polyurethane elastomers (PUEs) will experience different strain rates in different application scenarios. Therefore, it is of great significance to study the mechanical properties of PUE under a wide range of strain rates and establish a constitutive model that considers strain rates with high accuracy and few parameters. In this study, the quasi-static and dynamic compression tests of two types of PUEs (PUE55 and PUE85) were carried out, and investigated the strain rate effect of the materials. Based on the Mooney-Rivlin hyperelastic model and the Prony series, a compressible visco-hyperelastic constitutive model for PUE was established. Different from the conventional constant relaxation time in Prony series, two relaxation times that vary exponentially with principal stretch were proposed based on the relaxation test to describe the strain rate effect of the material at low and high strain rate respectively. In addition, using the visco-hyperelastic constitutive model to obtain the model inputs of the Simplified rubber/foam model in LS-DYNA, the impact process of the Metal/PUE composite projectile was reproduced under different impact conditions through the finite element simulation. Simulation results verified the visco-hyperelastic model in generating numerical model material parameters and the rationality of the Simplified rubber/foam model in describing PUEs.

This study investigates the use of cotton ropes (CRs) as a sustainable and cost-effective substitute for synthetic fiber-reinforced polymers for concrete confinement, offering significant environmental benefits such as lower CO2 emissions and reduced energy consumption. The work evaluates the effectiveness of CR strips for confining concrete, including scenarios with recycled concrete aggregates (ReCA). Compressive strength improvements varied among specimens, with Specimen I-3F showing a 140.52% increase and Specimen II-3F achieving a 46.67% improvement. Strip configurations for Type I recycled aggregate concrete (RAC) outperformed full wraps on Type II RAC, exemplified by Specimen I-3S’s 84.51% improvement. Ultimate strain enhancements ranged from 915% to 4490.91%, driven by the significant rupture strain of cotton rope confinement. For Type I RAC, complete wrapping significantly outperformed strip configurations by 56%, 50%, and 32% in ultimate strength improvement for 1, 2, and 3 layers, respectively. The confinement ratio, varying from 0.10 to 0.70, greatly influenced the compressive behavior, with compressive strength normalized by unconfined strength increasing consistently with the confinement ratio. A minimum confinement ratio of roughly 0.40 is required to achieve an increasing second part in the compressive behavior. The initial parabolic branch was modeled using Popovics’ formulation, revealing an elastic modulus approximately 20% lower than ACI 318-19 predictions. The second branch was described using a linear approximation, and nonlinear regression analysis produced expressions for key points on the idealized compressive curve, enhancing model accuracy for CR-confined RAC. The R2 values for the nonlinear regression analysis performed on experimental results were greater than 0.90. This study highlights the effectiveness of neural network expressions to predict the compressive strength of CR-confined concrete. A strength reduction (ratio of full wrap and strip wrap height CRs) factor of 0.67 was proposed and used for strip-wrapped specimens. It was seen that the neural network models also predicted the compressive strength of partially wrapped specimens with reasonable accuracy using the strength reduction factor.