Reduce Energy Dissipation Research Articles

Bamboo-inspired lightweight, mechanically-stable and vibration-damping structural members for engineering applications

After millions of years of natural evolution, bamboo stems have formed exquisite variable cross-section hollow multi-node structures that are lightweight, tough, and stable. Bamboo is difficult to break and damage from the roots under dynamic loads, providing an important reference for te biomimetic design of lightweight components. This paper investigates the structural characteristics and variation patterns of bamboo stems and subsequently proposes an imitation bamboo stem structure design strategy for engineering structural members, namely, imitation bamboo double-jointed columns (IDJC). We establish a macro scale finite element model to predict the mechanical properties and failure modes of the IDJC under cyclic bending loads, and validate the model using experimental and analytical methods. The simulation and experimental results show that compared with traditional double-jointed columns (DJC), the weight of the IDJC is reduced by 41.7 %. Under bending load, the compressive stress of each section is approximately equal, reducing stress concentration, and increasing bending resistance. The strength to weight ratio of IDJC is 1.96 times that of DJC, indicating lightweight and high-strength characteristics. The stiffness degradation, energy dissipation, and damping and vibration reduction performance of the IDJC were also evaluated. The results showed that compared with the DJC, the stiffness degradation rate of the IDJC decreased by 6.87 times, the energy dissipation rate increased by 1.07 times, and the damping and vibration reduction performance improved by 48.40 %, reflecting a high stability and robust vibration reduction performance. The results demonstrate the potential application of biomimetic structures for the development and design of resource-rich, low-carbon, and sustainable bamboo for bamboo engineering members with excellent performance and functionality. Biomimetic structures have great potential in replacing nonrenewable structural materials in the fields of civil engineering and transportation.

Experimental research on seismic performance of dry-wet combined precast concrete beam-to-column connections

In order to enhance on-site assembly efficiency and construction organization flexibility, a new type of dry-wet combined precast concrete beam-column connection was proposed. The prefabricated beams and columns were joined together using local post-tensioned tendons to create a temporary frame structure with dry connections. Subsequently, the wet connections between the prefabricated beams and slabs were established by pouring cast-in-place top concrete. A monolithic connection and four full-scale precast connections were subjected to reversal cyclic loading, with each designed incorporating distinct types of post-tensioned (PT) tendons, bonding conditions, and grouting materials. The test results indicate that the new connection exhibits flexural failure at the beam ends. In comparison to cast-in-place connections, it demonstrates enhanced deformation capacity, comparable ductility, higher stiffness, and reduced energy dissipation due to slippage of the PT tendons and steel bars. However, the viscous damping exceeds 15 %, thereby satisfying the seismic resistance requirements. The high-strength mortar grouting material satisfactorily fulfills the anchoring requirements of steel bars within the corrugated steel ducts, whereas the prestressed grouting material falls short in this regard. The overall performance of the new connection can be further enhanced by improving the grouting material and implementing local unbonded measures.

Mechanical behavior of the extended end-plate connections of a portal frame with various retrofitted constructions under loading

With the mounting number of photovoltaic power generation panels on roofs, the proliferation of heavier cranes, the addition of interlayers, and extreme weather conditions, the loads imposed on portal frame structures have observably increased, resulting in a strong demand for retrofitting. However, there remains a dearth of quantitative assessment regarding the efficacy and superiority of retrofitting techniques for beam-column connections with a bolted extended end plates (BCCBEEPs). Given that the retrofitting process cannot be characterized by complete unloading, it is crucial to accurately comprehend the impact of preload on retrofitting. In this study, finite element models (FEMs) of BCCBEEPs with seven different retrofitted constructions were established and validated against experimental results, and their mechanical behaviors were thoroughly compared and analyzed. Moreover, the influence of the preload level on the retrofitted BCCBEEPs was explored. The analysis results reveal that: excessive reinforcement of the component was found to shift the weak link to the connection, making the bolts more prone to failure and reducing energy dissipation capacity and ductility. Compared to an un-retrofitted connection, the carrying capacity of the PSPF retrofit measure, for which steel plates were pasted on the inside of beam flange, was found to be increased by a maximum of 38%. However, the energy dissipation capacity was decreased by 39%, the bolt tension was increased by 61%, and the prying force was increased by 58%. Importantly, not only components, but also connections, must be strengthened. Excessive preloads can lead to increased vulnerability at connection areas of retrofitted connections, especially in cases of over-reinforcement. The higher the preload level, the greater the reduction in bearing capacity, which could potentially fall below that of an un-retrofitted connection. When the preload level reached 80% of the strength of un-retrofitted connection, compared to the no-preload connection, the PSPF measure experienced a decrease of 18% in carrying capacity, a reduction of 31.8% in ductility, an increase of 14% in bolt tension, and a rise of 27% in end plate prying force. Therefore, when the preload level exceeds 20%, it is advisable to accurately assess the impact of the preload on the retrofit before implementation.

Multi-objective optimization of electro-pneumatic braking process with fuzzy logic control for heavy haul railway applications

ABSTRACT This paper presents a novel approach to multi-objective optimization in heavy haul trains’ electro-pneumatic braking systems using optimizable fuzzy control. Initial findings indicate that a straightforward replacement of pneumatically controlled valves with electro-pneumatic ones, without significant control schedule modifications, fails to substantially improve the dynamics behaviour of rolling-stock. Consequently, a more sophisticated strategy based on optimizable fuzzy logic control for the electro-pneumatic valves was developed. This approach utilizes multi-objective optimization to simultaneously minimize energy dissipation during braking and reduce force peaks in freight car draft gears. The optimal solution achieved demonstrates a 13.41% reduction in kinetic energy dissipation during downhill sections, along with a concurrent decrease in draft gear peak forces by 14.22% in traction and 3.16% in buff regimes compared to standard rolling-stock with pneumatically controlled valves. This optimized fuzzy braking controller outperforms standard procedures, highlighting its potential to enhance heavy haul train efficiency while adhering to safety standards.

Energy dissipation and seismic response reduction system for high-speed railway bridges based on multiple performance requirements

The emergence of high-speed railway bridges in regions with high seismic intensity has brought attention to the growing seismic challenges associated with these structures. Although the prevalent use of friction pendulum bearings for seismic isolation in China has proven effective in mitigating the seismic response of bridges, it falls short of meeting the safety standards required for high-speed trains. To address the limitations of existing isolation systems, this study employs a combined approach of numerical simulation and experimental research, leading to the invention of performance-controllable isolation bearing and multi-directional energy dissipation dampers. Mechanical models for both components were introduced, and design methods for their key parameters were established based on multi-level seismic defense requirements. By integrating these advancements, a novel cooperative seismic isolation system for high-speed railway bridges was created. Under the influence of moderate earthquakes, the system relies on the shear key to meet the stiffness requirements for normal service. During large earthquakes, the shear key is sheared off, and the damper provides momentary stiffness to control track deformation, enabling the safe stopping of trains. This combination forms a seismic isolation system during large earthquakes, ensuring the safety of railway bridges. The numerical analysis of a high-speed railway bridge employing a cooperative seismic isolation system demonstrates substantial mitigation in the response of both the pier bottom and pier top. This aligns with seismic requirements for the bridge structure. Additionally, the reduction in train track deformation meets safety standards, confirming the seismic performance of bridges and ensuring the reliability of train operations.

Hydrodynamic performance optimization of a cost-effective WEC-type floating breakwater with half-airfoil bottom

Aiming to design and develop an affordable integrated floating breakwater and wave energy converter (WEC) system that has high performance in power absorption and wave attenuation, a novel integrated floater with a half-airfoil bottom is proposed. The genetic algorithm combined with the boundary element method is employed to optimize the half-airfoil bottom surface represented by the class-shape function transformation parameterization method, for maximizing the power density over the operating bandwidth. Then the operating performance of the optimal half-airfoil bottom floater is further studied in a validated two-dimensional viscous numerical wave tank. The result shows that the optimal half-airfoil bottom floater is a more effective and affordable solution than square and triangular bottom ones. The effective ratio of the floater breadth to the wavelength can be reduced to about a tenth, far below that of the conventional floating breakwater, denoting its excellent wave attenuation capability. The increase in floater breadth induces more intense vortex dynamic behaviors and thus higher dissipation coefficient. A shallow front-wall draft design can improve the maximum conversion efficiency to more than 74%, slightly broaden the resonance bandwidth, and reduce energy dissipation while minimizing costs. The nonlinear PTO damping force contributes to a more stable response. The research results denote the feasibility of bio-inspired WEC-type floating breakwaters and show their superiority in energy extraction, wave attenuation, as well as cost reduction.

Marine Plant Growth Promoting Bacteria (PGPB) inoculation technology: Testing the effectiveness of different application methods to improve tomato plants tolerance against acute heat wave stress

Regenerative agriculture aims to boost native biodiversity and ensure sustainable production. Plant Growth Promoting Bacteria (PGPB) enhance crop yield through improved nutrient use efficiency or stress tolerance. Utilizing synthetic bacterial communities (SynCom) tailored to specific challenges holds promise for enhancing plant resilience. However, challenges include designing microbial consortia and selecting SynCom application techniques. This study tested four PGPB SynCom application methods on tomato plants to evaluate their effectiveness in promoting plant resistance and recovery from short extreme heat waves. Non-invasive phenotyping techniques were used to assess plant responses to three delivery methods (watering, foliar spray, and alginate spheres immobilization) under heat stress. Plants treated with the marine PGPB SynCom through methods like leaf spraying or encapsulation in alginate spheres exhibited improved resilience in terms of Kautsky curve intensity and shape, indicating better photochemical apparatus function. These techniques also facilitated post-stress recovery. Deep photochemical analysis revealed SynCom-induced improvements in the plant's photochemical apparatus, particularly the PS II donor side. Moreover, it was also possible to observe that upon stress relief these two techniques, alongside the plants inoculated throughout watering were able to recover their photochemical profiles. Analysing the Fv/Fm values, plants inoculated through watering, alginate beads and leaf spray can be considered heat-tolerant, a characteristic conserved throughout the three sampling moments. Heat-wave exposure led to an increase in the energy absorbed by the non-inoculated plants as a counteractive measure to overcome the low energy use efficiency observed (low trapping and transported energy fluxes). The reduction in stress impact was attributed to SynCom's ACC-deaminase production, which lowered ethylene accumulation, promoting growth and photosynthetic efficiency. The study also noted reduced energy dissipation under stress relief, indicating efficient heat dissipation mechanisms due to SynCom application. Statistical models generated with the attained photochemical data allowed depicting specific fluorescence signatures of each thermal and inoculation treatment with a very high degree of accuracy, reinforcing that these different inoculation treatments have in fact different impacts on plant photochemistry but also provide a tool for future phenotyping assessments using the proposed inoculation techniques. Alginate bead based PGPB release emerged as an efficient, scalable technique with continuous benefits for plant growth and stress response.

The crosstalk of far-red energy and signaling defines the regulation of photosynthesis, growth, and flowering in tomatoes

This study investigated the effect of light intensity and signaling on the regulation of far-red (FR)-induced alteration in photosynthesis. The low (LL: 440 μmol m−2 s−1) and high (HL: 1135 μmol m−2 s−1) intensity of white light with or without FR (LLFR: 545 μmol m−2 s−1 including 115 μmol m−2 s−1; HLFR: 1254 μmol m−2 s−1 + 140 μmol m−2 s−1) was applied on the tomato cultivar (Solanum Lycopersicon cv. Moneymaker) and mutants of phytochrome A (phyA) and phytochrome B (phyB1, and phyB2). Both light intensity and FR affected plant morphological traits, leaf biomass, and flowering time. Irrespective of genotype, flowering was delayed by LLFR and accelerated by HLFR compared to the corresponding light intensity without FR. In LLFR, a reduced energy flux through the electron transfer chain along with a reduced energy dissipation per reaction center improved the maximum quantum yield of PSII, irrespective of genotype. HLFR increased net photosynthesis and gas exchange properties in a genotype-dependent manner. FR-dependent regulation of hormones was affected by light signaling. It appeared that PHYB affected the levels of abscisic acid and salicylic acid while PHYA took part in the regulation of CK in FR-exposed plants. Overall, light intensity and signaling of FR influenced plants' photosynthesis and growth by altering electron transport, gas exchange, and changes in the level of endogenous hormones.

A low-resistance local component design method based on biomimicry and a random forest model: A pipe elbow case study

The energy consumption of building transmission and distribution systems accounts for more than 30% of building energy consumption, and the prevalence of localized components in building transmission and distribution systems leads to severe energy losses and resistance effects during system operation. To solve this problem, our research team has developed a series of resistance reduction components. This paper proposes a low-resistance local component shape optimization method based on biomimicry and machine learning, taking pipe elbows as an example, and the normalized shape optimization parameters of elbows with different pipe diameters are given. Through numerical simulation, full-size experiments, energy dissipation analysis and other methods, the optimized elbow resistance reduction effect and resistance reduction mechanism are verified and analyzed. The results showed that the resistance reduction rate of the elbow was 19%–26% for different pipe diameters and Reynolds numbers, and the optimized elbow significantly reduced energy dissipation during the flow process. Previously, the shape optimization problem of local components focused mainly on rectangular ducts that can be simplified in two dimensions; this study extends the optimization objective to circular pipes, which provides an effective method for guiding the optimal design of low-resistance local components in building transmission and distribution systems.

The Impact of Using Renewable Energy Resources on Sustainable Development in the Kingdom of Saudi Arabia

This study examines the impact of renewable energy on sustainable development in the Kingdom of Saudi Arabia from 2000 to 2019 and analyzes the kingdom’s most essential practices in this field to achieve sustainable development. The Cobb–Douglas production function is used in this study to investigate the impact of renewable energy on sustainable development using ordinary least squares (OLS) estimation. According to the findings, renewable energy consumption has a negative but insignificant effect on GDP. Additionally, traditional energy consumption has a major negative influence on GDP. The findings also demonstrate that fixed capital formulation and technical progress have a significant positive impact on Saudi Arabia’s sustainable development. Furthermore, while the labor force has a positive impact on GDP, this effect is not statistically significant. This report provides some recommendations for Saudi government policymakers to reform the country’s energy efficiency and consumption technologies in order to reduce energy waste and satisfy the goals of sustainable development. While the labor force is recognized as having a positive influence on GDP, it is notable that this result lacks statistical significance. The suggestions of these findings are mainly applicable to Saudi policymakers, and we present recommendations to improve energy competence and utilization technologies. Specially, our suggestions are intended to reduce energy dissipation and to support the objectives of sustainable development.

Effect of silica type, content, and silanization on the curing, mechanical and energy dissipation properties of poly (epichlorohydrin-co-ethylene oxide-co-allyl glycidyl ether) elastomers

This work aimed to determine the effect of unmodified raw silicas and modified silicas with silane coupling agents on the curing, mechanical, and energy dissipation properties of poly (epichlorohydrin-co-ethylene oxide-co-allyl glycidyl ether) based elastomers. The modified silicas utilized include Coupsil 6109, Coupsil 8113, and Coupsil VP6411, while the unmodified silicas are Ultrasil VN2 and VN3. Adding modified silicas increased the optimum curing time and decreased the cure rate index up to a silica content of 20 phr. However, the cure rate index increased with the addition of 40 phr silica. Mechanical testing of the compounds highlighted the impact of silica addition on the reinforcement of the rubber matrix. The incorporation of silica resulted in enhanced mechanical properties, including increased tensile strength, elongation at break, and elastic modulus. The compression behavior of the vulcanized compounds is also analyzed. The results show that the modified silicas with silane coupling agents exhibit lower relative hysteresis loss than the unmodified silicas, highlighting their potential for reducing energy dissipation and improving mechanical efficiency. Additionally, the storage modulus (G') values of the unmodified silicas (VN2 and VN3) are higher than those of the silanized silicas. However, in compounds prepared with 20 phr silica, the differences in storage modulus (G') between the modified and unmodified silicas are minor. Overall, the findings highlight the influence of modified silicas with silane coupling agents and unmodified silicas on the properties of PECH elastomer, providing insights into optimizing silica content for desired material characteristics.

An Ultra-Energy-Efficient Reversible Quantum-Dot Cellular Automata 8:1 Multiplexer Circuit

Energy efficiency considerations in terms of reduced power dissipation are a significant issue in the design of digital circuits for very large-scale integration (VLSI) systems. Quantum-dot cellular automata (QCA) is an emerging ultralow power dissipation approach, distinct from traditional, complementary metal-oxide semiconductor (CMOS) technology, for building digital computing circuits. Developing fully reversible QCA circuits has the potential to significantly reduce energy dissipation. Multiplexers are fundamental elements in the construction of useful digital circuits. In this paper, a novel, multilayer, fully reversible QCA 8:1 multiplexer circuit with ultralow energy dissipation is introduced. The power dissipation of the proposed multiplexer is simulated using the QCADesigner-E version 2.2 tool, describing the microscopic physical mechanisms underlying the QCA operation. The results show that the proposed reversible QCA 8:1 multiplexer consumes 89% less energy than the most energy-efficient 8:1 multiplexer circuit previously presented in the literature.

Flow Investigation and Optimization Design of a Radial Outflow Liquid Turbine Expander for Liquid CO2 Energy Storage System

Abstract The radial outflow liquid turbine expander (LTEROF) draws increasing attention for enhancing the efficiency of the liquid CO2 energy storage (LCES) system. However, the detrimental cavitation deteriorates the flow behavior, which demands an in-depth study of the flow physics and then effective attenuation. This study aims to effectively mitigate thermosensitive fluid cavitation and reduce energy dissipation. First, a preliminary expander design methodology taking into account the large specific volume variation of working fluid is implemented. Next, the entropy production analysis method (EPAM) is proposed to characterize energy dissipation and cavitation. Furthermore, the improved cavitation and turbulence models are validated through simulating Hord's liquid hydrogen hydrofoil. To suppress the cavitation and energy dissipation, the optimization design method based on the particle swarm optimization (PSO) algorithm together with the Kriging-based adaptive surrogate model is developed. Among them, the nonuniform relational B-splines and free form deformation (NURBS-FFD) method is applied to flexibly deform the profiles of nozzle and rotor, and a novel objective function incorporating vapor volume fraction and local entropy production rate (LEPR) is constructed to capture the cavitation and energy dissipation. During optimization, the optimizer is driven by the objective function to search globally toward the cavitation-resistance and low-dissipation geometry. With the optimization, the LEPR region shrinks and the cavitation is obviously weakened, the performance significantly improves both under design condition and under off-design conditions.

Distance-Distributed Energy Efficient Clustering (D-DEEC) Routing Protocol for Wireless Sensor Network

A wireless sensor network (WSN) composed of many tiny devices that rely on energy efficient routing protocols for extension of their lifetime. Many cluster-based routing protocols have been proposed based on heterogeneity in recent times. Indeed, these protocols are aiming at achieving energy efficiency, throughputs and better lifetime of the networks. However, two important factors that could have helped some of these protocols to achieve the above-mentioned aims are really missing. Factors such as the distance and average distance between nodes and the Base Station (BS) in selecting a cluster head needed to be considered. These were the major challenges that were identified in the Distributed Energy Efficient Clustering (DEEC) protocol after careful study. As a result, the throughputs and the lifetime of the scheme were affected. In this paper, a reviewed hierarchy-based heterogeneous routing protocol called Distance-DEEC (D-DEEC) is proposed to enhance the DEEC protocol. The new algorithm took into account the residual energy, distance of the individual nodes and average distance of all the nodes from the BS in selecting the Cluster Heads (CHs). This has allowed the protocol to select a cluster head that has high residual energy, is closer to the BS and at the same time not too far from its neighbours. The scheme also employed the sleep and awake approach to reduce energy dissipation. The technique allows the Base BS to calculate the maximum energy of distant nodes and determines when such nodes can transmit their report based on a given threshold energy, Eth . The performance of the proposed algorithm was evaluated using MatLab R2018a and the outcomes showed that, D-DEEC protocol outperformed TDEEC in terms of energy consumption, throughputs and the network lifetime.

Experimental study on the impact resistance of bamboo scrimber beams under impact loading

Drop-weight impact tests were conducted on bamboo scrimber beams to assess their resistance to dynamic stress. The study focused on investigating the influence of impact orientation, velocity, and cross-section size on failure modes and mechanical behavior. A comparison of data between dynamic impact and static load conditions consistently showed failure via cracking at the bottom of the beam. The severity of damage increased with impact velocity. Beams with greater stiffness exhibited less deformation, increased peak force, and reduced deflection. The energy absorption increased nonlinearly with impact speed, eventually stabilizing at higher velocities. Additionally, it was observed that increased stiffness led to a slight reduction in energy dissipation. The study also demonstrated the presence of inertia effects in bamboo beams during impact and proposed a design approach for enhancing impact resilience. Furthermore, a predictive model was developed to estimate the maximum deflection under dynamic conditions.

Modeling of Electrostatic and Contact Interaction between Low-Velocity Lunar Dust and Spacecraft

The accumulation of highly adhesive dust on spacecraft presents a serious issue to hinder long-term extravehicular activity and the establishment of a permanent station on lunar surface. In contrast to the immediate physical damage caused by hypervelocity (>1.0 km/s) impacts, this adhesion observed at low-velocity (0.01 to 100 m/s) collisions can more unobtrusively and mortally degenerate the performance of equipment. This paper proposes a theoretical model aimed at comprehensively analyzing the dynamics of adhesion and escape phenomena occurring during low-velocity impacts between charged dust particles and spacecrafts enveloped by a plasma sheath. The electrostatic force is modeled using the image multipole method, and contact force is calculated based on the adhesive–elastic–plastic theory. The results reveal that the implementation of a dielectric coating possessing both low permittivity and low interface energy can substantially reduce energy dissipation during collisions. However, the ultimate adhesion on the surface or escape from the sheath for low-velocity charged dust is dominated by the long-range electrostatic interaction rather than short-range contact interaction. Positively charged particles of smaller sizes demonstrate a greater propensity for surface adhesion in comparison to negatively charged particles of larger sizes. Counterintuitively, without additional dust removal techniques, modifying the properties of the dielectric coating does not effectively reduce the accumulation of dust, which can be merely accomplished by decreasing the spacecraft’s potential. The model presented in this study serves as a crucial step toward understanding the mechanism of lunar dust pollution.

Emergence of nanoscale viscoelasticity from single cancer cells to established tumors

Tumors are complex materials whose physical properties dictate growth and treatment outcomes. Recent evidence suggests time-dependent physical properties, such as viscoelasticity, are crucial, distinct mechanical regulators of cancer progression and malignancy, yet the genesis and consequences of tumor viscoelasticity are poorly understood. Here, using Wide-bandwidth AFM-based ViscoElastic Spectroscopy (WAVES) coupled with mathematical modeling, we probe the origins of tumor viscoelasticity. From single carcinoma cells to increasingly sized carcinoma spheroids to established tumors, we describe a stepwise evolution of dynamic mechanical properties that create a nanorheological signature of established tumors: increased stiffness, decreased rate-dependent stiffening, and reduced energy dissipation. We dissect this evolution of viscoelasticity by scale, and show established tumors use fluid-solid interactions as the dominant mechanism of mechanical energy dissipation as opposed to fluid-independent intrinsic viscoelasticity. Additionally, we demonstrate the energy dissipation mechanism in spheroids and established tumors is negatively correlated with the cellular density, and this relationship strongly depends on an intact actin cytoskeleton. These findings define an emergent and targetable signature of the physical tumor microenvironment, with potential for deeper understanding of tumor pathophysiology and treatment strategies.

Compact hybrid silicon nitride and lithium niobate nano-film photoelectronic reversible logic gate

Photoelectronic hybrid logic operation improves digit circuit efficiency without any additional photoelectric conversion, especially a photoelectronic reversible logic gate may reduce energy dissipation. In this paper, a compact photoelectronic reversible logic gate is proposed based on a hybrid silicon nitride and lithium niobate nano-film waveguide. Tow Mach-Zehnder modulators are cascaded together to construct the main part of the compact photoelectronic reversible logic gate. The whole length of the gate is only 4.4mm, one hundredth of the length of the common proton exchange lithium niobate modulator. By operating at the wavelength of 1.55μm, the proposed Mach-Zehnder modulator only requires 4.9V voltage to complete a full cross-coupling, which is well compatible with CMOS technology. It is demonstrated that at the wavelength range of 1.4μm to 1.6μm, the average insertion loss is 0.6dB, the minimum crosstalk is -47dB, and the maximum extinction ratio is 41dB; in the voltage range of 4V to 6V, the average insertion loss is 0.63dB, the minimum crosstalk is -26dB, and the maximum extinction ratio is 22dB. These features indicate that the photoelectronic reversible logic gates have good performances, bringing the photoelectronic logic gates into a new design parameter space and providing a possible solution for easing the electronic bottleneck.

A versatile cold-curing wood adhesive derived from butylphenyl polyester

Although there have been notable advances in wood-based adhesive materials, the ability to rapidly bond wood under cold curing conditions at room temperature remains a challenge in these adhesives. Here, we report a new butylphenyl-derived polymer that can achieve super strong adhesion at room temperature by fast response at the wood interface. This behavior is achieved by the external reactive groups to create strong interfacial forces and the internal construction of organic-inorganic hybrid structures to reduce energy dissipation. Our research has established an effective method to modulate the viscoelasticity of the copolymer and optimize the adhesion properties of the adhesive at room temperature. The adhesive has a lap shear strength of 4.2 ± 0.17 MPa and also has a repair function that allows the repaired wood to withstand tensile forces of up to 470 N. It is anticipated that this dry, self-supporting, low-cost functional latex will be used as a commercial product for furniture restoration, wood industry and other applications.

Experimental and numerical studies of the multi-tube assembled buckling-restrained braces

In this paper, the multi-tube assembled bolt-connected buckling-restrained brace (MT-BRB) with four internally restrained rectangular steel tubes and one externally restrained square steel tube is experimentally analyzed. This study conducted cyclic loading tests on five specimens with different parameters to investigate the effects of different loading directions of the core plate, the presence or absence of unbonded materials, the gap-to-width ratio and the width-to-thickness ratio on the mechanical properties, seismic performance and failure mode of MT-BRB. The experimental results indicated that the MT-BRB specimens made of unbonded materials had stable cyclic performance and energy dissipation capacity. Subsequently, the same numerical model as the experimental specimen was established, and the hysteresis and stress curves extracted from the finite element model were compared with the experimental results. The simulation had ideal agreement with the experiment result, demonstrating that the model was effective for performance predictions. Based on this, the working mechanism of MT-BRB was further explored through finite element analysis. Finally, parameter analysis was conducted on the constraint ratio and constraint length ratio to further investigate the energy dissipation performance of MT-BRB. This study is beneficial for promoting the application of MT-BRB in energy dissipation and vibration reduction engineering.