Quasi-static Tests Research Articles

Optimizing mechanical properties and pioneering biodegradable polymer blends for superior energy-absorbing structures used in sport helmets

Replacing elements made of conventional plastics (like polystyrene) with biodegradable substitutes is part of the trend of sustainable development and waste reduction. The manuscript covers issues related to the design, manufacturing and testing of sports helmet protective inserts made of biodegradable material. The FEM numerical simulations carried out by the authors allowed to determine the optimal desirable mechanical properties (Re = 8.5–65 MPa, E = 500–8000 MPa for 30 × 30 mm inserts; Re = 10.5–60 MPa, E = 500–7500 MPa for 48 × 48 mm inserts; Re = 13–95 MPa, E = 400–8500 MPa for 55 × 55 mm inserts) and geometric parameters (wall thickness equal to 0.2–0.5 mm, height of 20 mm), ensuring the formation of a plastic fold, which is the most effective energy-absorbing mechanism. The conducted quasi-static compression, bending and dynamic tensile strength tests allowed to determine blends with appropriate proportions of durable PLA with more plastic PBAT, PBS and TPS that meet the established criteria: PLA50PBAT50, PLA30PBAT70 and PLA30TPS70.

Optimized enhanced energy absorption in polymer nanocomposites reinforced with nano-clay, nano-silica, and diethylenetriamine

In today’s world, where various industries face ever-increasing developments, improving people’s lives and preserving their property and lives are important issues in industrial production. One of the most unpleasant events in life is a collision while using the vehicle. Therefore, in recent decades, the high importance of this issue has attracted the attention of many researchers. The present study investigates the energy absorption of polymer nanocomposites with cylindrical and conical structures with different percentages of clay and silica nanoparticles to determine the various effects of nanomaterials and the effect of structure geometry on energy absorption under quasi-static tests. This experiment has been designed with the help of Design Expert software and the Box-Benken method. Also, nanomaterials between changes of 0-0.4% and diethylenetriamine material with weight% 1,3,5 have been used. From the results, it can be depicted that with the increase of the nanomaterial in this range, energy absorbed by the addition of nano silica up to the central point, i.e., 0.2%, an increase has been witnessed and after that, its intensity has decreased. Within this range, there is an observed significant rise of up to 0.4% for the nano clay material, while its trend keeps up with the previous intensity after the central point. However, in diethylenetriamine material, the highest energy absorption at the central point was 0.2%, after which a downward trend was observed. Also, in the investigation of the geometry of the structure, it was found that cone-shaped structures have higher energy absorption.

Experimental and numerical simulation of seismic behavior of reinforced concrete frames infilled with refractory straw blocks

Recent earthquakes have highlighted the vulnerability of infilled reinforced concrete structures due to the insufficient consideration of infill masonry walls' contribution to strength and stiffness. This study presents a novel refractory straw block (RSB) designed to address these challenges and improve the seismic performance of reinforced concrete (RC) frames. Unlike traditional infills, RSB is characterized by low-elastic-modulus, low-density, and high-ductility. Quasi-static tests were performed on three types of frames: unfilled, infilled hollow grouted bricks (HGB), and infilled RSBs. Failure model, stiffness, and load-displacement response of three specimens were investigated and analyzed. The results indicate that RSBs as infill material does not alter the failure mode and constitutive relationship of bare frame, while HGBs leads to shear failure. The peak load for the specimen IF-HGB was 69.3 kN at 1.1 % drift, compared to 38.8 kN at 2.4 % drift for the specimen IF-RSB, and 36.4 kN at 2.0 % drift for the specimen BF. The strengths of specimens IF-HGB and IF-RSB were 1.90 and 1.07 times that of specimen BF, respectively. The stiffness of specimen IF-HGB was 3.7 times that of the other specimens, but its allowable displacement was only 61 % of theirs. Dynamic time-history analyses were also performed on structures with no longitudinal infill (BF), with RSBs (SBF), and with fired bricks (FBF). At the design level of rare events (magnitude 8, PGA 400 gal), severe damage occurred, but collapse was limited. When the PGA increased further, the collapse probability of model FBF rose rapidly, whereas the collapse probabilities of models SBF and BF remained low and similar. Accounting for the confining effect of walls, model FBF showed a higher probability of severe damage than models SBF and BF, particularly under minor earthquakes. The maximum inter-storey drift ratio of the model SBF and FBF were respectively 1.2 times and 1.7 times that of the model BF, which shows that straw blocks as infill can greatly avoid the effect of infill on the seismic behavior of the structure. The study also emphasized the often-overlooked confining effect of masonry on columns, which can lead to unrealistic damage assessments and seismic shear force distributions.

Dynamic behaviour of ultra-high performance concrete beams with rectangular openings subjected to impact loads

To facilitate residents’ needs, contemporary building structures often incorporate prefabricated transverse openings in reinforced concrete (RC) beams to accommodate pipeline installations. However, these openings can potentially impact the load-bearing capacity of the beams, particularly as structures increasingly need to consider dynamic loading effects. The use of ultra-high performance concrete (UHPC) has proven effective in enhancing the dynamic resistance of RC beams with openings. This study employs numerical simulations in ANSYS/LS-DYNA to investigate the dynamic response of UHPC beams with rectangular openings exposed to low-velocity impact. The calibrated Continuous Surface Cap (CSC) model is primarily validated through quasi-static four-point loading tests on UHPC beams with openings. Following this validation, numerical simulations of drop hammer impact are carried out to comprehensively analyse the behaviour of UHPC beams with openings. Furthermore, parametric investigations are performed to evaluate the impact response of UHPC beams with large or small openings, considering various design factors such as opening size, opening position, stirrup quantity and UHPC strength level.

Seismic performance and calculation method for plastic hinge length of RC pier reinforced with UHPC

Piers are highly vulnerable load-bearing components, and their seismic performance determines the integral seismic resistance of bridges to a certain degree. They play crucial roles in evacuation during earthquakes and post-earthquake rescue. The manner in which piers meet the seismic performance requirements after reinforcement has become a popular research topic. In this study, ultra-high-performance concrete (UHPC) and HTRB600E high-tensile reinforcements were used to expand the cross section of a cast-in-place square pier with severe bending damage. The earthquake-resistant behaviour indicators of the pier were compared and analysed by conducting pseudo-static tests on a reinforced concrete pier before and after reinforcement. These indicators included the hysteretic curve, skeleton curve, energy dissipation curve, rigidity degradation, residual displacement, and pier body curvature. Based on the results of the seismic reinforcement quasi-static tests, a finite element model (FEM) of the bridge pier was constructed using the ABAQUS software, and the accuracy of the FEM was averaged. The impact of the reinforcement layer height, thickness, longitudinal strength and axial compression ratio on the equivalent plastic-hinge length of the reinforced pier was analysed, and the formula for the equivalent plastic-hinge length of the reinforced pier was obtained based on multiple linear regression fitting. The analysis results demonstrated that the broadened section method, utilising UHPC and high-tensile reinforcement, significantly enhanced the flexural capacity, energy dissipation, and first rigidity of the bridge pier. The earthquake-resistant behaviour of pier was effectively restored and improved, and the seismic reinforcement effect was significant. The equivalent plastic hinge length of the pier after reinforcement is proportional to the height of the reinforcement layer, the thickness of the reinforcement layer, the strength of the longitudinal reinforcement, and inversely proportional to the axial compression ratio.

Experimental investigation of seismic performance of precast concrete shear walls with overlapping U-bar loop connections

This paper discusses the seismic performance of five reduced-scale shear walls, including one cast-in-place (CIP) concrete shear wall, two precast concrete (PC) shear walls with overlapping U-bar loop connections, and two PC shear walls with modified form-overlapping U-bar loop connections combined with extruded sleeve connections. A quasi-static test was conducted to evaluate the reliability of the overlapping U-bar loop connections and the modified form by comparing the corresponding mechanical parameters of PC specimens with those of the CIP specimen. Moreover, the differences in seismic performance between the CIP specimen and PC specimens with different connection methods were also analyzed in terms of damage process, hysteretic loops and skeleton curves, load carrying capacity, ductility, equivalent stiffness, and energy dissipation. The experimental findings indicated that the mechanical performances of PC specimens with the modified connection form outperformed those of PC specimens with pure overlapping U-bar loop connections, closely resembling the properties of cast-in-place specimens; the failure mode of PC specimens was consistent with that of the CIP specimen; the generation, distribution and development of cracks in PC specimens were also similar to those in the CIP specimen. Furthermore, although the load-bearing capacity and peak displacement of PC specimens were lower than those of the CIP specimen due to the failure of the post-casted concrete strength to meet the requirements, the ductility, equivalent stiffness, and energy dissipation of PC specimens with the modified connection form closely matched that of the CIP specimen.

Theoretical derivation and seismic design method on self-centering piers with ED members validated using numerical simulations and quasi-static tests

Theoretical derivation and seismic design method on self-centering piers with ED members validated using numerical simulations and quasi-static tests

3D-printable Kresling-embedded honeycomb metamaterials with optimized energy absorption capability

Abstract Kresling origami structure has attracted significant interest for achieving extraordinary mechanical properties. In this study, we proposed a new strategy to develop 3D-printable Kresling-embedded honeycombs (KEHs) based mechanical metamaterials and achieve optimized mechanical energy absorption capability. By exploiting the twisted deformation modes and boundary constraints, various KEH reinforced metamaterials were designed, where their deformation behaviors and energy absorption properties were investigated using finite element analysis and quasi-static compression tests. Effects of orientation twisting angle, boundary constraint and crease tilting angle on the deformation behaviors of these KEH reinforced metamaterials were studied to optimize their energy absorption properties. Finally, deformation behaviors and energy absorption properties of KEH reinforced metamaterials incorporated of KEH arrays in both 2D structure and 3D structures were studied. Both experimental and simulation results showed that the proposed KEH reinforced metamaterials achieved much more stable compression behaviors and higher energy absorption capabilities than those of the traditional honeycomb structures. This study provides a novel KEH reinforcement strategy for 3D printed metamaterials with optimized energy absorption capabilities to dramatically expand their practical applications.

Mechanical properties and restoring force model of Squeezing Rub-type Particle Damper

The sliding effect of isolation bearings has been proven to effectively mitigate the seismic effects on large-span bridges. However, it also results in excessive relative displacement between the main girder and piers during earthquakes. In this study, a pioneering Squeezing Rub-type Particle Damper (SRPD) is developed to address this issue. In order to verify the damping characteristics of SRPDs and investigate the working principle of squeezing friction energy dissipation, five quasi-static tests were conducted on SRPDs using two particle damping materials with different compactness levels. In order to compare the energy dissipation performance, comparative tests were conducted on Non-Squeezing-type Particle Dampers (NSPDs) and SRPDs. Utilizing regression analysis, two skeletal curve models for SRPDs were proposed, alongside a detailed restoring force model that incorporates considerations for both the pinching effect and stiffness degradation phenomena observed during the loading and unloading phases. The experimental results demonstrate that the maximum damping force of SRPDs can reach 16 times that of NSPDs, and the energy dissipation of each loading cycle can reach 21.06 times that of NSPDs. SRPDs exhibits improved energy dissipation performance when using high-density blended quartz sand. After sand replenishment repairs,damping force and energy dissipation per cycle of SRPDs were significantly enhanced. The proposed restoring force models of SRPDs aligns well with the experimental curves, underscoring its efficacy in accurately characterizing the hysteresis performance of SRPDs.

Investigation of the Influence of Different Filler Contents of Wine Pomace in PBS on Fracture Mechanics Properties

Biobased polybutylene succinate (PBS) represents a promising alternative to petrochemical-based polymers. The use of this biopolymeris limited in many areas by its low resilience against environmental influences. With the help of bio-based stabilizers the thermo-oxidative degradation process can be slowed down. Suitable stabilizing additives are natural antioxidants present in plant extracts with a high flavonoid content, which can be found in grapes, wine and wine by-products. PBS was modified with two different bio-stabilizers based on wine grape pomace. The highest filler content tested was 20 wt.-%. In addition to improving stability, the additives also impact the polymer’s mechanics. The influence of these functional fillers on the fracture mechanical properties was examined in a quasi-static test. The crack growth was recorded using integrated video monitoring. Based on the results, the corresponding crack resistance curve and tearing modulus were determined depending on filler type and content. Additional optical analysis was used to correlate fracture mechanics and structure. The two bio-stabilizers based on red (RWP) and white wine pomace (WWP) differs distinctly in terms of their influence on fracture mechanical properties. The Influence of RWPon the fracture toughness is significantly higher than that of WWP. Especially at lower filler contents with RWP, there is a strong increase in the fracture mechanics parameter tearing modulus (TJ) and an increase in the slope of the R-curve. With 5 wt.% RWP DOM the TJ is 13.64 x 102, whereas with WWP Silv a value of only 6.39 x 102 can be achieved. This difference is also reflected in the increase in the R-curves. With 5 wt.% a slope of the fitted R-curve of 265.59 (RWP DOM) and 121.02 (WWP Silv) could be determined with the first derivative. In the optical analysis it was noticeable that the RWP particles were more homogeneously dispersed in the matrix while the WWP filler tended to agglomerate. The inhomogeneous distribution and strong agglomeration tendency can be attributed to a higher sugar content of WWP and a higher particle size distribution. The top cut (D97) of WWP Silv is 62.37 ± 0.05 µm and that of RWP DOM is 51.97 ± 0.09 µm.

Flexural Behavior of 3D-Printed Carbon Fiber-Reinforced Nylon Lattice Beams

This study investigates the flexural behavior of 3D-printed multi-topology lattice beams, with a specific emphasis on octet and cube lattice geometries created through fused deposition modeling (FDM). The mechanical properties of these beams were evaluated through quasi-static three-point bending tests. A comparative analysis of load-carrying capacity, energy absorption, and specific energy absorption (SEA) indicates that octet lattice beams exhibit superior performance to cube lattice beams. The octet lattice beam in the triple-layer double-column (TL-DC) arrangement absorbed 14.99 J of energy, representing a 38% increase compared to the 10.86 J absorbed by the cube lattice beam in the same design. The specific energy absorption (SEA) of the octet beam was measured at 0.39 J/g, which exceeds the 0.29 J/g recorded for the cube beam. Two distinct types of deformations were identified for the struts and the beam layers. Octet struts exhibit enhanced performance in stretch-dominated zones, whereas the cube system demonstrates superior efficacy in compressive-dominated regions. The results highlight the enhanced efficacy of octet lattice structures in energy absorption and mechanical stability maintenance. The investigation of sandwich lattice topologies integrating octet and cube structures indicates that while hybrid designs may exhibit efficiency, uniform octet structures yield superior performance. This study provides valuable insights into the structural design and optimization of lattice systems for applications requiring high-energy absorption and mechanical robustness.

Compressive Mechanical and Heat Conduction Properties of AlSi10Mg Gradient Metamaterials Fabricated via Laser Powder Bed Fusion

Metamaterials are defined as artificially designed micro-architectures with unusual physical properties, including optical, electromagnetic, mechanical, and thermal characteristics. This study investigates the compressive mechanical and heat transfer properties of AlSi10Mg gradient metamaterials fabricated by Laser Powder Bed Fusion (LPBF). The morphology of the AlSi10Mg metamaterials was examined using an ultrahigh-resolution microscope. Quasi-static uniaxial compression tests were conducted at room temperature, with deformation behavior captured through camera recordings. The findings indicate that the proposed gradient metamaterial exhibits superior compressive strength properties and energy absorption capacity. The Gradient-SplitP structure demonstrated better compressive performance compared to other strut-based structures, including Gradient-Gyroid and Gradient-Lidinoid structures. With an apparent density of 0.796, the Gradient-SplitP structure exhibited an outstanding energy absorption capacity, reaching an impressive 23.57 MJ/m3. In addition, heat conductivity tests were performed to assess the thermal resistance of these structures with different cell configurations. The gradient metamaterials exhibited higher thermal resistance and lower thermal conductivity. Consequently, the designed gradient metamaterials can be considered valuable in various applications, such as thermal management, load-bearing, and energy absorption components.

Study on the evolution rules of coal deformation and failure characteristics caused by multiple mining disturbances

During coal mining operations, the coal will be deformed and damaged due to multiple mining disturbances (MMD), often resulting in disasters, like rock burst. To understand the evolution rules of coal deformation under MMD and its final fracture characteristics after impact dynamic load loading, reduce the adverse effects of mining disturbances, and improve disaster prevention and control capabilities, quasi-static uniaxial cyclic loading-unloading (L-U) and dynamic axial compression tests were conducted on large-sized coal-like samples. During the tests, three-dimensional (3D) laser scanning and acoustic emission (AE) monitoring technology were utilized to accurately capture the full-field deformation and AE response data, facilitating a systematic analysis of deformation and fracture characteristics. The results show that: (1) Under the cyclic L-U effect induced by MMD, each loading cycle causes compression deformation with partial recovery during unloading, presenting an overall “wavy” variation trend. (2) The maximum load is the most critical factor affecting the damaged coal deformation, with smaller load resulting in less overall sample deformation. (3) After the impact dynamic loading, the damaged samples suffered large-scale impact splitting failure, with the compressive-shear layer failure mainly occurred inside the holes. (4) Lower loading during cyclic L-U process correlate with reduced damage degree, and smaller debris particles with a higher fractal dimension when impact failure occurs, indicating a more severe impact failure. (5) With multiple cycles of L-U, the cracks inside the sample gradually extend and expand from around the hole to the outside. The greater the load and the number of cycles, the more serious the crack damage will be. (6) In the practical mining process, it is crucial to reinforce roadway interiors while minimizing low-loading cyclic disturbances induced by MMD. The study has obtained the deformation evolution rules and failure characteristics of coal under MMD, providing a theoretical basis for the prevention and control of corresponding engineering disasters.

Parameters Affecting Seismic Performance of Longitudinally Connected Track Lateral Blocks on Bridges Under Low-Cycle Reciprocating Loads

In the current seismic analysis of high-speed railway track–bridge structures, the constitutive parameters of track lateral blocks (TLBs) are not uniform. A finite element model of the TLB’s main beam is established, which considers concrete plastic damage, interface bond between old and new concrete, and bond slip between anchorage steel bars (ASBs) and concrete. Quasi-static tests of nine TLBs with different numbers and ASB diameters at a 1:2 scale was carried out to verify the accuracy of the TLB finite element model in terms of the failure pattern, interface damage, hysteretic properties, and skeleton model. Based on the verified TLB finite element model, the influence of different TLB design parameters on its seismic performance parameters was studied. The results show that the established TLB finite element model is in good agreement with the test data in terms of failure pattern, interface damage, hysteretic properties, and skeleton model, which verifies the accuracy of the TLB finite element model. ASB number has the greatest influence on the TLB yield load, followed by ASB diameter, concrete strength, ASB strength, and ASB spacing. ASB diameter has the greatest influence on the TLB peak load, followed by ASB number, ASB strength, concrete strength, and ASB spacing. ASB diameter has the greatest influence on the TLB energy dissipation capacity, followed by ASB number, concrete strength, ASB strength, and ASB spacing. With the increase in concrete strength and ASB strength, TLB ductility decreases. When the ASB number is higher than eight or the diameter is higher than 12 mm and the corresponding interfacial steel bar ratio reaches 0.82%, the TLB ductility will decrease.

Seismic behavior of resilient concrete column-base connection with SMA bolts and RSPs

This paper presented a novel resilient concrete column-base connection with shaped memory alloy (SMA) bolts and rectangular slotted plates (RSPs) to achieve the demountable and recoverable capabilities in precast concrete columns. Quasi-static tests were conducted on one monolithic and three resilient concrete connections to investigate the effects of RSP number and yield strength on seismic behavior. Results showed that the resilient connection with both flange and web RSPs had superior lateral capacity, ultimate drift ratio, and energy dissipation compared to the monolithic connection. The resilient connection also exhibited minimal concrete damage and smaller residual deformation. However, low-yield-strength flange RSPs significantly reduced lateral capacity, initial stiffness, and energy dissipation, which should be considered in engineering design. Additionally, adjustment coefficients for rocking interface rotations were determined from digital image correlation (DIC) data using a fitting method. A formula was proposed to predict the flexural capacity of resilient specimens, assuming a plane section in the compression zone. The predictions closely matched the test data, with differences within 10 %, demonstrating the formula's effectiveness. The length, diameter, and material yield strength of the anti-shear steel bar (ASB) had a significant impact on the shear capacity of the interface.

Stretchable printed circuit boards using a silicone substrate of variable stiffness and conventional PCB fabrication methods

Abstract Stretchable printed circuit boards (S-PCBs) offer unique advantages over rigid PCBs such as enabling conformability to changing environments and ergonomic designs with increased lifetime under dynamic loads. This study introduces an innovative fabrication method and a cost-effective solution for rapid prototyping S-PCBs using commercially available materials. By utilizing silicone substrates with different levels of stiffness and structured copper sheets for electrical connections, the S-PCBs feature ‘stiff islands’ embedded in a flexible base material. This fabrication method helps alleviate mechanical strain on strain-sensitive components while allowing local deformation of the S-PCB. The proposed fabrication method does therefore enable to integrate surface mount device components into S-PCBs and facilitates complex circuit designs while maintaining stretchability and fatigue resistance. Through material characterization, video strain analysis, as well as quasi-static and cyclic loading tests, this article demonstrates the efficacy of our approach. Based on the experimental results, we provide insights into failure modes and suggest design principles to further enhance the durability of S-PCBs fabricated with our method. We then conclude by presenting a soft wearable S-PCB demonstrator. The S-PCBs fabricated with this method withstood mechanical strains up to 100% and cyclic loads with 30% strain up to 625 cycles. The results are very promising for applications in soft robotics, wearable devices, and soft sensors and actuators. Overall, our study offers a comprehensive toolkit for fast S-PCB prototyping, paving the way for advancements in stretchable electronics with a high degree of complexity and stretchability.

Seismic isolation effect and parametric analysis of simply supported beam bridges with multi-level sliding friction adaptive isolation bearing

In response to the shortcomings of isolation bridge limit devices and friction dampers, a sliding friction bearing exhibiting multi-level working behavior (MSFB) is proposed. Its structure and mechanism are introduced, and a multi-condition quasi-static test is conducted using ABAQUS software. Through comparative analysis of theory and experiment, the theoretical model's accuracy and multi-level sliding friction mechanism of MSFB are verified. The mechanical parameters of MSFB are analyzed, clarifying the influence of various main mechanical parameters on the mechanical performance. The performance parameters of the MSFB are optimized based on a two-degree-of-freedom analysis model for a high-speed railway single-pier bridge equipped with MSFBs. The findings indicate that the seismic responses of MSFB is comprehensively affected by all the parameters, and the variation pattern is complex. By optimizing these performance parameters, MSFB can satisfy the multi-level performance demands of bridges subjected to varying earthquake intensities, and achieve the optimal control effect. The MSFB offers superior isolation efficiency during minor and moderate earthquakes and can substantially decrease the internal forces within the bridge substructure when utilized as a bridge isolation and limit device. During intense and infrequent earthquakes, the MSFB demonstrates remarkable displacement-limiting capacity and good self-centering and energy dissipation abilities.

Study on Dynamic Characteristics of Resilient Mount Under Preload.

Resilient mounts are essential for anti-vibration and shock absorption applications, making accurate predictions of their static and dynamic behaviors critical for effective design and mechanical performance. This study investigates static and dynamic characteristics of resilient mounts to predict their effects. Tension, compression, and shear tests were performed under quasi-static loading conditions to obtain stress-strain cycle curves. This study includes a review of the Yeoh hyperelastic model, which consists of three parameters, and discusses the calibration of these parameters to describe the hyperelastic material behavior. The parameters were validated through numerical analysis by comparing them with experimental results from quasi-static tests on the resilient mount. The dynamic behavior was further analyzed using modal analysis and frequency response simulations under various preload conditions. Results show that increasing preload significantly shifts the transmissibility curves and resonance peaks to lower frequencies. This study offers valuable insights into static and dynamic characteristics of resilient mounts, contributing to the design and optimization of vibration isolation systems for naval applications.

Seismic experiment and performance analysis on embedded optimized steel plate-reinforced concrete composite shear wall under multi-dimensional loading

In order to investigate the seismic performance of reinforced concrete shear walls under multi-dimensional loading mode and its effect on performance improvement, an embedded optimized steel plate-reinforced concrete composite shear wall is proposed. Based on the design principle that the shear wall could adequately bear multi-dimensional loading and the embedded steel plate could reach the full stress state, the X-shaped optimized steel plate (for in-plane loading mode) and the triangular optimized steel plate (for out-of-plane loading mode) are determined using different optimization methods. The combination scheme of these two plates is utilized in the oblique loading mode. Quasi-static loading tests are conducted on eight typical shear wall specimens, and performance parameters such as hysteresis curve, skeleton curve, ductility, stiffness degradation, strain evolution, and damage evaluation of the specimens are compared and analyzed. In addition, variable parameter analysis is performed using finite element software to compare the strain distribution state of each steel plate. The results indicate that the embedded optimized steel plate-reinforced concrete composite shear wall structure exhibits higher bearing capacity, greater deformation capacity, and superior energy dissipation capacity under different loading angles compared to the tradition reinforced concrete shear walls. This composite structure can provide greater lateral stiffness, and the optimized steel plate can reach the full stress state at all loading angles, effectively reducing the damage of steel bars and concrete. These findings offer a foundation for the study of seismic performance and performance improvement methods for shear wall structures under multi-dimensional earthquake action.

Bending response and energy absorption of sandwich beams with combined reinforced auxetic honeycomb core

This study introduces a reinforced star-shaped auxetic honeycomb (RSSAH) sandwich beam, enhanced with hollow thin-walled tubes to improve bending resistance and energy absorption performance. The bending performance of the RSSAH is systematically investigated through quasi-static three-point bending tests and finite element numerical simulations. The findings suggest that when subjected to mid-span stress, the RSSAH displays both localized indentation and overall bending deformation, accompanied by notable negative Poisson’s ratio (NPR) impact under bending loads. Parametric studies are undertaken by numerical simulations to investigate the impact of compression position, auxetic angle, and face sheet thickness on the bending mode of the auxetic honeycomb sandwich beam. The analysis shows that the RSSAH can exhibit excellent bending performance and, at one of the compression positions, displays double-plateau stress characteristics. It is also found that altering key geometric parameters, such as the auxetic angle and panel thickness ratio, can greatly improve the bending capabilities of the RSSAH, achieving stable plastic deformation and high energy absorption. Finally, compared to star-triangle honeycomb (STH) sandwich beam, traditional reentrant honeycomb (RH) sandwich beam and star-shaped auxetic honeycomb (SSAH) sandwich beam, the RSSAH demonstrates superior bending performance and energy absorption capacity. This study offers insights and references for the development of innovative reinforced auxetic honeycomb sandwich beams.