Energy Dissipation Systems Research Articles

Optimization of a novel lateral energy dissipation system for cable-stayed bridge with short piers based on seismic vulnerability analysis

Cable-stayed bridges with short piers are susceptible to becoming the structural weak link in seismic resistance during strong earthquakes. Traditional lateral restraint systems, such as fixed and sliding bearing systems, may impose substantial lateral forces and displacement demands, affecting the entire bridge's seismic safety. A butterfly-shaped steel plate damper has been developed and integrated into a lateral energy dissipation system along with elastoplastic cables to address this. Given the significant computational challenges and the complexity of identifying the optimal parameters for the energy dissipation system, this paper combines the probabilistic seismic demand model (PSDM) with the response surface method (RSM) to propose the seismic vulnerability fitting optimization method (SVFOM). Based on SVFOM, utilizing a central composite design (CCD), 17 analysis scenarios that account for the parameter variations of the lateral energy dissipation system are established. By developing response surface functions for bearing damage (ys) and pier damage (yp) through the seismic response fitting of the structure across all scenarios, we determined the optimal parameters for the lateral energy dissipation system to minimize damage to both bearings and piers. The finite element model validation analysis, which demonstrated significant reductions in pier displacement and the probability of bearing damage, confirms the effectiveness of the SVFOM. Optimized parameters showed that the new lateral energy dissipation system can significantly enhance the lateral seismic performance of cable-stayed bridges with short piers. Compared to scenarios without energy dissipation and with lateral sliding bearings, they demonstrated that this optimized system reduces the relative displacement of the piers and girders by 56 % and the probability of complete bearing failure by 87 % while maintaining pier damage within acceptable limits. This optimized system offers a valuable reference for the seismic design of similar bridge structures.

On the Complex Flow Dynamics of Shear Thickening Fluids Entry Flows

Due to their nature, using shear thickening fluids (STFs) in engineering applications has sparked an interest in developing energy-dissipating systems, such as damping devices or shock absorbers. The Rheinforce technology allows the design of customized energy dissipative composites by embedding microfluidic channels filled with STFs in a scaffold material. One of the reasons for using microfluidic channels is that their shape can be numerically optimized to control pressure drop (also known as rectifiers); thus, by controlling the pressure drop, it is possible to control the energy dissipated by the viscous effect. Upon impact, the fluid is forced to flow through the microchannel, experiencing the typical entry flow until it reaches the fully developed flow. It is well-known for Newtonian fluid that the entrance flow is responsible for a non-negligible percentage of the total pressure drop in the fluid; therefore, an analysis of the fluid flow at the entry region for STFs is of paramount importance for an accurate design of the Rheinforce composites. This analysis has been numerically performed before for shear-thickening fluids modeled by a power-law model; however, as this constitutive model represents a continuously growing viscosity between end-viscosity plateau values, it is not representative of the characteristic viscosity curve of shear-thickening fluids, which typically exhibit a three-region shape (thinning-thickening-thinning). For the first time, the influence of these three regions on the entry flow on an axisymmetric pipe is analyzed. Two-dimensional numerical simulations have been performed for four STFs consisting of four dispersions of fumed silica nanoparticles in polypropylene glycol varying concentrations (7.5–20 wt%).

Implementación de Disipador de Energía, TADAS

El Salvador is a country with high seismic demand, so the design and construction processes of buildings today areaimed at reducing the vulnerability caused by earthquakes, as part of the philosophy of damage mitigation and correct structural performance, there are Advances in detailing and construction techniques, so the use of deformation. energy dissipation systems is a safe way to prevent damage at a reasonable economic cost compared to the use of other more complex and sophisticated technologies. In El Salvador, the implementation of the TADAS (Triangular plate Added Damping And Stiffness) energy dissipation system has been implemented in a pioneering way and on a small scale, in the case of a two-story building, structured with Steel frames with ordinary detailing. The first level corresponds to parking, so the TADAS devices have only been installed in a longitudinal direction, while the second level corresponds to various uses of meeting people in meeting rooms and office work, so architectural issue the existence of windows with a view not interrupted by structural elements turned out to be a condition for not installing TADAS on that level. The final result meets the requirements of the ASCE-7-16 standard in deformation control, and prevention of structural damage due to the ductility that TADAS provides to the global structure. All the structural elements satisfy resistance and service requirements given by AISC-ANSI-36016. ILIA: Investigaciones Latinoamericanas en Ingeniería y Arquitectura, No. 01, 2024: 103-107.

Experimental and numerical investigation of a novel passive energy dissipation system with viscoelastic damper and angle-reaction controller

Sharp and significant changes in the relative angle between beam and column during earthquakes often lead to failure of structural joints. This study proposed a novel passive Energy Dissipation system (PEDs) consisting of a viscoelastic damper (VED) and an angle-reaction controller (ARC). The ARC provides mutual support to the joint by establishing temporary supports in reinforced concrete or steel frames to allow for free-angle multilevel control in the case of excessive relative angle. This feature distinguishes the novel PEDs from previous systems as it allows the reaction force of the temporary support to compensate for the loss of joint rotational stiffness. The cyclic loading tests were conducted by constructing fundamental components, and then a mechanical model for the novel PEDs was established. Numerical simulations were performed to analyze parameter variations and to provide a comprehensive methodology for evaluating the seismic performance of the novel PEDs. The results demonstrated that two mechanisms were effectively incorporated into the novel PEDs: vibration energy dissipation and protection against excessive angles. The multistage flag hysteresis curve confirmed the reliability of our theoretical model in representing this novel PEDs. Therefore, supplementing rotational stiffness while achieving energy dissipation can be considered a new approach for enhancing seismic performance in frame structures.

An Innovative Dual-Level Energy Dissipation System with Friction/Yielding Dampers: Numerical and Theoretical Approaches

An Innovative Dual-Level Energy Dissipation System with Friction/Yielding Dampers: Numerical and Theoretical Approaches

A cumulative damage model based on deformation-energy parameters for flexible barriers under multiple repeated impacts

Existing flexible rockfall barrier systems are frequently exposed to repeated rockfall impacts during use, yet research addressing the cumulative damage sustained by these systems remains limited. A novel numerical simulation method is proposed to study the effects of repeated impacts on flexible barrier systems, which considers the damage and deformation accumulation of components through a complete restart method. Two full-scale sequential impact tests were conducted to validate this numerical simulation method's effectiveness. The impact conditions for both tests were service energy level (SEL). The deformation behavior and energy dissipation mechanism of the flexible barrier system subjected to repeated impacts were examined. The findings indicate that the net serves as the primary component undergoing deformation during rockfall impacts, with the residual deflection of the wire-ring net accounting for approximately 61 % and 58 % of the system's overall residual deflection in the respective tests. Furthermore, the energy dissipators emerge as the principal components responsible for energy dissipation, constituting approximately 71 % and 64 % of the system's energy dissipation in the two tests, respectively. Considering that both the net and the energy dissipator are key components influencing the barrier system's ability to withstand rockfall impacts, they are also prone to experiencing the most severe damage. Methods for calculating the damage of the components have been devised. The residual deflection of the wire-ring net and the energy dissipated by the energy dissipators are employed as parameters for assessing damage. A method for estimating structural damage is developed using a two-parameter model for deflection and energy dissipation. A parametric analysis was conducted to evaluate the performance of the flexible barrier system under repeated impacts spanning impact energies from 100 kJ to 2000 kJ. The cumulative damage in both the barrier and its components is thoroughly investigated. A simplified criteria for assessing cumulative structural damage incurred as the barrier undergoes multiple repeated impacts is proposed. The study findings indicate a linear relationship between the number of impacts and both component and structural damage, with the slope of this relationship positively correlating with impact energy. Structural damage can be characterized by damage of the net and the energy dissipators, with the latter as the primary influencing factor. The findings presented in this paper offer valuable insights for informing engineering maintenance decisions.

Damped rigid substructure system for seismic protection of structures

Building codes commonly accept inelastic deformations that inevitably occur due to seismic excursions in structures. To control the damage, limits on the inelastic deformations have been established. Standard passive energy dissipation systems have been used to reduce the damage, generally with some effectiveness. The damped rigid substructure (DRS) passive damping system, proposed in this article, geometrically amplifies the damper displacements and exerts a re-centering force, leading to effective discharge of the seismic energy to the extent that structural damage can be prevented. This is achieved using common damped and undamped diagonals arranged per implementation and design principles introduced in this article. The DRS system can considerably reduce material consumption and construction costs, leading to more sustainable structures when seismic forces govern the design. It can also benefit from the usage of high-strength materials to enhance its re-centering mechanism. The system is adaptable to the architectural needs and can be used for all categories of importance and height variation, made of steel or concrete.

Experimental response of semi-rigid reinforced concrete beam-column joints with bolted angle dissipating connections

Accelerated building construction is a challenge and opportunity for modern construction techniques such as prefabricated building. However, insufficient connection detail for precast structures resulted in serious damages (even collapse) in past earthquake, which significantly hit the further development of prefabricated building. With satisfactory seismic performance and minimal residual displacement, self-centering joint is an excellent alternative with respect to traditional prefabricated joint. In self-centering system, bolted connections are sufficiently utilized as energy dissipation system. However, the information about connection details is quite limited. Thus, a comprehensive experimental study was conducted to characterize the seismic behavior of semi-rigid reinforced concrete (RC) beam-column joints with bolted angle dissipating connections, namely, semi-rigid joints. Ten full-scale semi-rigid joints were tested under cyclic loading, taking the connection detail as variable. The main configurations of semi-rigid joints based on Eurocode 3 were angle thickness, angle stiffener, bolt diameter, column bolt gauge, rows of beam bolts, and grouting of beam bolts. The test results showed that, by adopting the ductile connection concept, it was possible to produce high ductility and abundant energy dissipation, control damages within the connection zone, and even achieve equivalent monolithic behavior through mobilizing a sufficient rigidity. Feasibility of replacing the damaged connection with a new one with the identical or higher capacity thus obtaining the equivalent or better performance with respect to the original tested joint is also evaluated. Finally, a theoretical model was proposed to evaluate the initial stiffness and bearing capacity of the joints. A good correlation was achieved as comparing to the test results. This research provides significant insight into the performance of precast semi-rigid joints and offers essential data for further investigation of developing design-oriented procedures.

Efficient design of truss footbridges with stiffness-proportional inerters

Absract Excessive vibrations in footbridges have recently received more attention from researchers and professionals. This has resulted in a surge in popularity for passive energy dissipation systems, such as tuned mass dampers, viscous dampers, and inerters. While design methods with tuned mass dampers and viscous dampers exist, the design of footbridges using inerters is still a challenge. This paper proposes a design procedure for truss-like footbridges incorporating inerters. The concept of the approach is based upon a mathematical derivation of the eigenproblem of a multi-degree-of-freedom structural system, enhanced with stiffness-proportional inertances. This outcome enables tuning the highest natural frequency of the system to a predefined value. The proposed design procedure adjusts all natural frequencies, such that the highest natural frequency of a structural system is set lower than the frequency of the load. As implemented in the article, the procedure can be used for back-of-the-envelope estimations, or for achieving an efficient final design. The designs achieved by the suggested methodology are compared to the current traditional design, optimal design achieved through gradient-based sizing optimization, and designs with various common topologies. The methodology’s high potential and its proximity to optimal for a chosen topology are revealed.

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.

Fracture-Resistant Stretchable Materials: An Overview from Methodology to Applications.

Stretchable materials, such as gels and elastomers, are attractive materials in diverse applications. Their versatile fabrication platforms enable the creation of materials with various physiochemical properties and geometries. However, the mechanical performance of traditional stretchable materials is often hindered by the deficiencies in their energy dissipation system, leading to lower fracture resistance and impeding their broader range of applications. Therefore, the synthesis of fracture-resistant stretchable materials has attracted great interest. This review comprehensively summarizes key design considerations for constructing fracture-resistant stretchable materials, examines their synthesis strategies to achieve elevated fracture energy, and highlights recent advancements in their potential applications.

Numerical and experimental investigation of negative stiffness beams and honeycomb structures

Metamaterial structures that exhibit negative stiffness (MSNS) behavior have shown the potential to be used as energy dissipation systems in different applications. Negative stiffness honeycomb structures consist of multiple pre-buckled beams that snapping through from one pre-buckled mode to another buckled mode, when subjected to transverse loads, displaying negative stiffness, and dissipating a significant portion of the input energy. This paper presents finite element models (FEMs) developed to investigate the performance of negative stiffness pre-buckled beams and honeycombs. The FEMs were validated using experimental results of single pre-buckled beams and honeycomb structures. The experimental testing of the pre-buckled beams was presented in the current study while the results of the honeycomb were available in the literature. The FEMs have the ability to capture the transition of the elements from one mode of buckling to another mode as well as the force thresholds, energy dissipation values, and residual displacements. The FEMs were extended to investigate the effect of different parameters such as boundary condition, apex height-to-beam thickness ratio, and constraining the second mode of buckling on the behavior of negative stiffness honeycombs.

Experimental and numerical investigations of a novel parallel double-stage crawler-track-shaped shear damper

In this study, a novel parallel double-stage crawler-track-shaped shear damper (PDCSD) was developed, which is fabricated using thin-walled steel plates. An asynchronized double-stage working mechanism was achieved based on the parallel energy dissipation (inner and outer crawler-track-shaped steel plates), restraining (upper and lower restraining plates), and load transfer (outer and inner blockers with initial clearance) systems. Accordingly, theoretical equations for the skeleton curve of the PDCSD and the design load for the load transfer system were proposed. The double-stage working mechanism and performance of the PDCSD were verified based on full-scale seismic and fatigue performance tests. Subsequently, based on refined finite element analyze, the working mechanism of the PDCSD was revealed and the theoretical equations were validated. A simplified model of the PDCSD with an emphasize on the hysteretic behavior was conclusively recommended and validated against the test and simulation results obtained from the refined numerical models, providing an accurate and efficient approach for the seismic response control of structures equipped with PDCSDs.

Seismic mitigation of continuous girder bridges equipped with U-shaped stainless steel dampers under near-fault earthquake excitations

Bridges that are close to seismic faults may suffer from severe damages under earthquake excitations. To enhance the seismic performance of continuous girder bridges, this paper presents a combined energy dissipation system (CEDS), incorporating isolation bearings and U-shaped stainless steel dampers. The U-shaped stainless steel dampers are equipped between every two bearings, and the top and bottom ends of dampers are fully fixed with the girders and the bent caps, respectively. Considering the strained conditions under seismic loadings, the mechanical property of U-shaped stainless steel dampers is numerically investigated with the loading directions of 0, 45, and 90 degrees. The hysteretic behavior of U-shaped stainless steel elements affected by the geometric parameters, i.e., the width, the thickness, the radius of arc segment, and the length of straight section, are further investigated. After that, a continuous girder bridge is adopted to verify the feasibility of the combined energy dissipation system, and two groups of U-shaped stainless steel dampers are designed for continuous piers and transition piers, respectively. The results turn out that the U-shaped stainless steel element shows excellent energy dissipation capacity. The maximum relative displacement between the girders and bent caps of piers can be effectively reduced by adopting the CEDS, which prevents the girders falling from supporting seats, and it is more effective in the longitudinal direction of bridges with the seismic reduction rate of 20–70%. Though the installation of U-shaped stainless steel dampers enhances the constrict of the top of piers, the maximum drift ratio increases in an acceptable range.

Numerical Investigation of Cyclic Behavior of Angled U-shaped Yielding Damper on Steel Frames

Yielding dampers are often selected as a cost-effective solution for improving steel structures compared to other energy dissipation systems. The objective of this research study was to investigate the cyclic behavior of the angled U-shaped yielding damper (AUSYD) on a steel frame using numerical method. The numerical model was first verified using two experimental samples. Next, the influence of the number of dampers on the cyclic behavior of the steel frame was examined. The parametric model outcomes included energy dissipation, elastic stiffness, strength, and equivalent viscous damping ratio (EVDR). Additionally, an analytical equation was proposed for calculating the ultimate strength of the AUSYD, which correlated well with the experimentally obtained results. The study findings revealed that the increase in elastic stiffness and strength of the frame equipped with the AUSYD was nearly equivalent to the sum of the elastic stiffness and strength of the bare frame and its supplementary dampers. Furthermore, the results showed that models with 8 to 12 dampers had comparable energy dissipation and EVDR. Adding 8 dampers to the frame increased the energy dissipation and damping coefficient of the frame by 42% and 67%, respectively.

Influence of Extruded Tubing and Foam-Filler Material Pairing on the Energy Absorption of Composite AA6061/PVC Structures.

There is accelerating demand for energy-absorbing structures fabricated from lightweight materials with idealized, near-constant force responses to simultaneously resolve the engineering challenges of vehicle mass reduction and improved occupant safety. A novel compounded energy dissipation system composed of AA6061-T6 and AA6061-T4 tubing subjected to hybrid cutting/clamping and H130, H200 and H250 PVC foam compression was investigated utilizing quasi-static experiments, finite element simulations and theoretical modeling. Identical structures were also subjected to axial crushing to compare with the current state of the art. The novel cutting/foam crushing system exhibited highly stable collapse mechanisms that were uniquely insensitive to the tube/foam material configuration, despite the disparate material properties, and exceeded the energy-absorbing capacity and compressive force efficiency of the axial crushing mode by 14% and 44%, respectively. The simulated deformation profiles and force responses were consistent with the experiments and were predicted with an average error of 12.4%. The validated analytical models identified numerous geometric/material configurations with superior performance for the compounded AA6061/PVC foam cutting/foam crushing system compared to axial crushing. An Ashby plot comparing the newly obtained results to several findings from the open literature highlighted the potential for the compounded cutting/foam crushing system to significantly outperform several alternative lightweight safety systems.

Dual hydrogen-bonding network strategy enables fabrication of robust soy protein adhesive capable of excellent bonding at ambient temperature

The application of biobased soy protein adhesives is significantly limited by poor initial adhesion during assembly. This deficiency leads to weak interfacial adhesion and cohesion toughness attributed to insufficient intermolecular interactions. In this study, we propose a dual hydrogen bonding system within a waterborne epoxy emulsion (WEU), in which the 2-ureido-4[1 H]-pyrimidinone (UPy) moiety with quadruple hydrogen bonds is grafted onto an epoxy skeleton, and polyethylene glycol (PEG) blocks with regular weak hydrogen bond sites is used to emulsify the WEU by simple mixing. WEU then acts as a crosslinker to improve the mechanical performances of high-temperature soybean meal (HSM) wood adhesives. The introduction of UPy and PEG blocks contributes to the formation of a dense cohesion crosslinking network and an energy dissipation system via multiple hydrogen bonding with peptide chains, enhancing the cold-pressing bond strength of adhesives with a 140% increase, relative to that of a pure HSM adhesive. Thermocuring facilitates interfacial penetration and covalent links via an epoxy ring-opening reaction in the system, creating a secondary crosslinking platform to optimize the water resistance and toughness of the adhesives. Consequently, the cured HSMW-15 adhesive exhibits an improvement in wet bond strength from 0.11 MPa to 0.90 MPa, with optimal toughness at 2.74 MJ/m3. This effective and feasible design provides valuable insights into modification strategies for preparing biobased wood adhesives with superior performance.

Experimental, mathematical model, and simulation of a dual-system self-centering energy dissipative brace equipped with SMA and variable friction device

The application of shape memory alloy (SMA) in seismic-resistant devices has received extensive attention due to its unique superelastic and shape memory effect. The poor energy dissipative capacity, insufficient reliability, and small bearing capacity are the main challenges that hinder the application of the developed SMA braces and dampers. The new system of self-centering energy dissipative (SCED) brace was proposed, fabricated, and tested, and the numerical model was defined and verified. The dates manifest that the load-displacement curve of the new dual-system SCED brace displays a typical flag shape. The new dual-system SCED brace exhibits the desirable energy dissipative ability and self-centering capacity and the theoretical and FE model established in this research can preferably express the hysteretic performance. The FE parametric analysis shows that the SMA screw preload has a small effect on the hysteretic curve of the new system brace, but it plays a decisive role in the shape of the hysteretic curve under small deformation. Furthermore, the bearing capacity and stiffness of the dual-system SCED brace can be adjusted by designing key parameters. The research shows that the new dual-system SCED device compensates for the shortcomings of the existing SMA braces and dampers, and it is a very promising and recommended self-centering energy dissipative device to use the wedge block system as the main energy dissipative system and SMA system as the main self-centering system.

Nanoconfined Water-Ion Coordination Network for Flexible Energy Dissipation Device.

Water-ion interaction in a nanoconfined environment that deeply constrains spatial freedoms of local atomistic motion with unconventional coupling mechanisms beyond that in a free, bulk state is essential to spark designs of a broad spectrum of nanofluidic devices with unique properties and functionalities. Here, wereport that the interaction between ions and water molecules in a hydrophobic nanopore forms a coordination network with an interaction density that is nearly four-fold as that of the bulk counterpart. Such strong interaction facilitates the connectivity of the water-ion network and is uncovered by corroborating the formation of ion clusters and the reduction of particle dynamics. Wedesign a liquid-nanopore energy dissipation system and demonstrate in both molecular simulations and experiments that the formed coordination network controls the outflow of confined electrolytes along with a pressure reduction, capable of providing flexible protection to personnel and devices and instrumentations against external mechanical impacts and attacks. This article is protected by copyright. All rights reserved.

Seesaw-arm energy dissipation system with U-shaped steel dampers

This paper presents an investigation of the extended seesaw system using a seesaw-arm member with U-shaped steel dampers for improving the seismic energy dissipation in building structures. One of the notable features of the existing seesaw system is its usage of a quasi-linear motion mechanism, which allows the bracing members to remain tensile during vibration. In addition, a seesaw-arm concept is proposed for magnifying the damper deformation. Evaluation methods for the lateral stiffness and strength of the proposed system were derived. Then, cyclic loading tests were performed on six specimens, revealing that the proposed system has a stable hysteretic property and large energy-dissipation capacity. The accuracy of the stiffness and strength evaluation was assessed through comparisons with the test results. The evaluation of the displacement amplification factor of the damping system agreed well with the test results. Seismic-response analyses of five-story steel frame models adopting the proposed system were conducted. The maximum story drift angle, time-history responses of displacement and energy, and plastic-hinge formation were compared with those of the bare frame model. The analysis results revealed the efficiency of the proposed system for reducing seismic responses. Furthermore, a larger shape factor of the seesaw-arm member corresponded to better seismic performance.