Nonlinear Energy Dissipation Research Articles

Assessing the dissipative capacity of particle impact dampers based on nonlinear bandwidth characteristics

The dissipative capacity as quantified by the nonlinear bandwidth measure of impulsively loaded linear primary resonators or primary structures (PSs) coupled to particle impact dampers (PIDs) is assessed. The considered PIDs are designed by initially placing different numbers of spherical, linearly viscoelastic granules at various 2D initial topologies and clearances. The strongly nonlinear and highly discontinuous dynamics of the PIDs are simulated via the discrete element method taking Hertzian interactions, slipping friction caused by granular rotations into account. An extended definition of nonlinear bandwidth is used to evaluate the energy dissipation capacity of the integrated PS-PID systems. To this end, the time-bandwidth (T-B) product is defined by nonlinear bandwidth in tandem with characteristic time. The T-B product is studied as a measure of the capacity of these systems to store or dissipate vibration energy. It is found that the initial topologies of the granules in the PID drastically affect the T-B product, which, depending on shock intensity, may break the classical limit of unity of linear time-invariant dissipative resonators. The optimal PS-PID systems composed of multiple granules produce large nonlinear bandwidths, indicating strong dissipative capacity of broadband input energy by the PIDs. Moreover, the granular collect-and-collide regime yields high nonlinear bandwidth and efficient energy dissipation capacity, whereas the opposite is observed for the granular gaseous state regime. The relationship between energy dissipation by the PID and nonlinear bandwidth of the PS are discussed, and it is found that as the shock intensity increases these two measures tend to vary similarly. The implications of these findings on the study of the dissipative capacity of the PS-PID system are discussed, yielding a predictive methodology for designing PIDs to act as highly effective nonlinear energy sinks capable of rapid and efficient suppression of vibration induced by shocks.

Comparison of forcing schemes to sustain homogeneous isotropic turbulence

Studies of forced homogeneous isotropic turbulence (HIT) of multiphase systems rely on a comprehensive understanding of the single-phase HIT flow to quantify any turbulence modifications due to injection of the dispersed phase. Here, we compare external forcing schemes to generate and sustain single-phase HIT. The considered forcing schemes, Lundgren, Arnold–Beltrami–Childress, and Mallouppas, are based on the application of the body force in physical space to inject energy into the flow at large length scales. Direct numerical simulations are performed in cubic periodic domains of 1283 and 2563 size using a lattice Boltzmann method. The range of the Taylor's Reynolds number achieved is ReλT=24.4–75.4. The Lundgren force takes the longest time to generate turbulence and produces significant fluctuations in the turbulence properties in the statistically stationary state. Additionally, this force interacts with the velocity field in the entire range of wavenumbers, which is not the case for the other two forces. However, the scale-by-scale analysis shows that for the considered forces, the behavior of the non-linear energy transfer, dissipation, and energy injection terms differs only within the initial 16% of the wavenumbers that represent large length scales. After that, all terms behave consistently among each other for different forcing schemes. We conclude that the three considered large-scale forcing schemes do not affect the generated turbulent flow fields at small scales and can be used to study turbulence modification by the dispersed phase.

Mixed convection phenomenon for hybrid nanofluid flow exterior to a vertical spinning cylinder with binary chemical reaction and activation energy

The study of hybrid nanofluids over spinning cylindrical configurations is widely used in numerous engineering and technological applications. Compared to conventional coolants, nanofluids explore superior thermal conductivities and thereby promote outstanding heat transport capabilities. In this study, hybrid nanofluid flow and thermal transmission across a vertical spinning cylinder are examined in the presence of an externally applied transverse magnetic field. The working fluids used are Ag/water nanofluid and Al2O3-Ag/water hybrid nanofluid. The analysis of heat transmission is carried out in the presence of slip and convective conditions, nonlinear thermal radiation, activation energy, and viscous dissipation. Partial differential equations (PDEs) are used to model the physical situation and are subsequently transformed into ordinary differential equations (ODEs). Through the use of MATLAB's bvp4c technique for ODEs, graphical and computational results are produced and validated with previously reported studies. The important findings are that the flow field diminishes as the magnetic field parameter and Reynolds number increase. Further, for larger levels of nano particle's fraction and thermal Biot number, the thermal features increase. Moreover, it is noted that the mass diffusion rate is lowered by the system's activation energy.

Seismic resilient design and negative stiffness-assisted nonlinear isolation system for adjacent non-coaxial buildings linked by corridors

Adjacent non-coaxial buildings have been widely built owing to complementary functions, while the non-coaxial layout could cause a great torsion effect and seismic-induced damage. This study proposes a negative stiffness-assisted hybrid isolation system and a corresponding earthquake-resilient design methodology to upgrade the multi-performances of the adjacent non-coaxial buildings and linking corridors. The hybrid isolation system includes synthetic employment of various isolators and negative-stiffness amplification systems comprised of nonlinear viscous dampers for adjacent structures, as well as tailored friction bearing for linking corridors. The mechanical property and model of the adjacent non-coaxial buildings are established, based on which a typical case is introduced. Next, the conception of the earthquake-resilient design method and procedure is elaborated, following which the functionality of each component in the hybrid system is investigated. The advantages of the developed hybrid isolation system and design methodology are illustrated by a systematic parametric analysis and time history analysis for the typical case. The results show that the torsional effect can be a dominant problem in non-coaxial adjacent buildings, which can be solved by the flexibly tailored negative stiffness effect produced by the negative stiffness-assisted isolation system. The collaboration within the proposed hybrid isolation system can produce improved isolating and enhanced nonlinear energy dissipation effects on adjacent buildings, simultaneously limiting the isolation displacement without weakening the isolating effect. The optimized friction sliding bearings effectively reduce the relative torsion concentrated on the linking corridors with a maintained function. The hybrid isolation system and earthquake-resilient design can be adopted as a high-efficiency solution to the non-coaxial linked historic buildings with insufficient seismic resistance.

Bioconvective Carreau nanofluid flow with magnetic dipole, viscous, and ohmic dissipation effects subject to Arrhenius activation energy

This article mainly involves a novel study of electric as well as magnetic field effects in the presence of magnetic dipole on Carreau nanofluid flow filled by gyrotactic microorganisms over a stretched sheet under the influences of nonlinear thermal radiation, activation energy, chemical reaction, viscous and ohmic dissipation. Bioconvection becomes an important area of research when magneto nanoparticles (ferrofluid) suspended with motile microorganisms, as collectively they have wide range of applications. The suspension of nanoparticles in microorganisms are found beneficial in nanofluid stability. A class of appropriate similarity functions is utilized to convert steady nonlinear PDEs into a set of ODEs and then computed numerically by applying two distinct techniques bvp4c in MATLAB and Maple ′ dsolve ′ command. For limited cases, we have also compared our outcomes with already published work and found in good agreement. The impact of various controlling parameters active in the velocity, temperature, concentration, and density profiles are observed and presented extensively. Additionally, for engineering aspects, the numerical computations as well as graphical presentations for surface drag force, Nusselt/Sherwood numbers(the wall heat and mass fluxes) and density of motile organisms are also performed for both types of fluids (i.e., n = 0.5 and n = 1.5). All the four profiles, i.e., density of motile microorganisms ( Ψ ( η ) ) concentration ( ϕ ( η ) ), thermal ( θ ( η ) ), and velocity ( f ′ ( η ) ) vary for shear thinning and thickening cases. The concentration profile decelerates for rising Chemical reaction rate and fitted rate constant but rises by increasing the activation energy. Outcomes of Skin friction coefficient and heat transfer rate are higher for shear thickening liquid as compared with shear thinning liquid.

Seismic performance of double-column tall pier bents using fusing connections

The dynamic responses of tall pier bridges with single column have been extensively investigated, while the research on double- or muti-column tall pier bent bridges is limited to date. This paper investigates the seismic performance of this type of tall pier bents and proposes a fusing connection between pier columns and link beams, to alleviate damage and improve seismic resilience. By setting strength hierarchies among various components, the proposed fusing connection is designed to yield prior to both column and link beam. Therefore, the nonlinear damage and energy dissipation during earthquakes are shifted to these connections, and the pier column and link beam are protected. To validate the efficiency of the proposed fusing connections, a typical double-column tall pier bent constructed at Southwest China is employed as a prototype. Through the nonlinear time history and fragility analysis procedures, the performance of the tall pier bent using fusing connection is evaluated and compared with the prototype in deterministic and probabilistic ways, respectively. The results show that the utilization of fusing connections effectively suppresses both the section curvature and shear force demands of pier columns. Thus, the seismic vulnerability of the prototype is reduced, and the seismic performance is improved, in both linear and nonlinear stage. Furthermore, the link beams are also protected by the connections and remain elastic during excitations, indicating lower probability of secondary damage, as well as reduced post-earthquake repair work and cost.

Nonlinear energy dissipation and transfers in coarsening systems.

During coarsening, small structures disappear, leaving behind only large ones. Here we study the spectral energy transfers in Model A, where the order parameter ϕ evolves via nonconserved dynamics. We show that the nonlinear interactions dissipate fluctuations and facilitate energy transfers among the Fourier modes so that only ϕ(k=0), where k is the wave number, survives at the end and approaches the asymptotic value +1 or -1. We contrast the coarsening evolution for the initial conditions with 〈ϕ(x,t=0)〉=0 and with uniformly positive or negative ϕ(x,t=0).

Simultaneous features of ternary hybrid nanoparticles on thermal radiative flow configured by Darcy–Forchheimer porous surface

Due to its remarkable thermodynamic development in various engineering sciences, the dispersion of nanostructures in classical base liquids is receiving greater attention from researchers and scientists. In light of the aforementioned inspirations, the suggested research is associated with using a water-based ternary-hybrid nanofluid that contains three unique nanostructures, silicon dioxide, titanium dioxide and aluminum oxide to optimize the heating process in science and engineering. In this situation, the influence of a chemically reactive magneto-hydrodynamics (MHD) Darcy–Forchheimer ternary hybrid composites transport involving nonlinear radiation across an exponentially permeable stretched surface is highlighted with the model’s physical initial and boundary constraints. The simulation of the heat expression also includes the impacts of nonlinear thermal radiations, energy supply, energy dissipation and magnetic force. Furthermore, the interpretation of Buongiorno’s theory involves spontaneous and thermophoresis diffusions. Entropy analysis is explained using the second law of thermodynamics. We converted the model framework for fluid movement, energy and mass transfer (together with ternary hybrid nanofluid characteristics) into self-similar nondimensional differential equations, that were then further analytically evaluated by using the homotopy asymptotic method (HAM) technique via Mathematica software. The acquired results are illustrated numerically and graphically to study the behavior of fluid flow, heat, concentration distribution, drag force, rate of heat and mass transfer for various emergent components to gain scientific comprehension. With the growing values of magnetic, porosity and Forchheimer number, the nature of the velocity profile goes down.

A new approach to atmospheric turbulence measurements using HOSE on radar backscattered echoes

A Novel approach has been proposed for the measurement of turbulent energy dissipation rate (ε) from Nonlinear index (NLI) based measurements using the Higher Order Spectral Estimation (HOSE) technique. The higher order spectral analysis, also known as Bispectrum, is useful for identifying nonlinearities present in the signals. Earlier studies used Bispectrum measurements to experimentally study the spectral energy transfer due to wavenumber interactions in a turbulent flow, which is briefly discussed in the manuscript. This is one of the main motivations for considering HOSE on Atmospheric signals. The Bicoherence obtained by this method has been applied to the backscattered signals received from the Mesosphere, Stratosphere, and Troposphere (MST) radar, Gadanki. Here we considered both convective and clear air atmospheric observations for the analysis and calculated the Nonlinear Index (which represents the amount of nonlinearity in signals) obtained from the Bicoherence for each range bin. We observed that the nonlinearity index indirectly provides information about turbulent intensity. An empirical relationship between the nonlinear index and turbulent energy dissipation rate has been established through regression models. The results of the turbulence energy dissipation rate (ε) obtained from the nonlinear index based method have been compared with the turbulence energy dissipation rate (ε) obtained from the spectrum width based method.

Recycled Plastic Lumber walls for one and two-story housing: An assessment of their seismic performance

Recycled Plastic Lumber (RPL) is a sustainable material that has been proposed in the last years to develop structural systems for low-rise housing in high-seismic hazard zones to reduce plastic pollution and housing deficit. Recently, experimental and analytical studies have been conducted to determine the behavior and the damage states of RPL walls under cyclic loads, and promising results have been obtained. Based on that results, a Mostaghel’s six-lines hysteretic model was implemented to simulate the nonlinear behavior and energy dissipation capacity of the RPL walls. Subsequently, the seismic performance assessment of the RPL walls was obtained by nonlinear dynamic analyses using the FEMA P-695 far-field ground motions, which allowed develop fragility functions to estimate the probability of exceeding certain damage states as a function of an intensity measure of seismic hazard. The results of this study evidence that the RPL walls have a suitable seismic performance for their implementation in low-rise housing and meet precisely the Basic Safety performance objective established in the design philosophy of the NSR-10 Colombian building code for this kind of buildings.

Impact of entropy analysis and radiation on transportation of MHD advance nanofluid in porous surface using Darcy-Forchheimer model

The proposed research is concerned with water-based ternary-hybrid nanofluid with nanostructures SiO2, TiO2 and Al2O3 for cooling purposes in engineering. A reactive MHD Darcy-Forchheimer liquid flow involving radiation effect across an exponentially permeable stretched surface is highlighted. Heat expression includes the impacts of nonlinear thermal radiations, energy supply, energy dissipation and magnetic force. The obtained results are demonstrated numerically and graphically to examine the behavior of fluid speed and temperature distribution for various emerging factors in order to gain a physical understanding. Entropy analysis is explained using the second law of thermodynamics. The values of Cf,Nu and SG are also calculated for the various parameters and physically explained.

Shaking table test study on seismic performance of RC frame structure with NES

A new type of nonlinear vibration absorber NES (Nonlinear Energy Sink) studied in this paper belongs to the structural passive control technology, which consists of a horizontal track and an additional mass block. Acting as a damper absorb and dissipate energy, the NES completes the target energy transfer by generating a horizontal nonlinear restoring force and reduces the response of the main structure. In this paper theoretical analysis of the new NES was analyzed by the expression of the restoring force of the NES and the equation of motion of the additional NES system are deduced. Shaking table test was carried out on the 1:4 scale RC frame structure model installed with the new NES shock absorber, focusing on the research on the energy dissipation and shock absorption effect of the NES shock absorber, and whether it can improve the seismic performance of the RC frame structure damaged in the earthquake. The results show that the NES installed in the RC frame structure has sufficient nonlinear displacement and energy dissipation capacity under the moderate and strong earthquakes, showing a very good energy dissipation and shock absorption effect. The NES can reduce the top story displacement and acceleration response of the main structure under the action of earthquake; the top story displacement and absolute acceleration response are related to the natural frequency of the frame and the spectral characteristics of seismic waves, so that the vibration control effect is affected by the frequency spectrum of seismic waves. In the frequency domain analysis of the frame dynamic response, the nonlinear energy well exhibits the characteristics of broadband control. This type of NES significantly reduces the seismic response of damaged structures, improves the seismic performance of damaged structures under moderate to strong earthquakes, and decreases the risk of potential collapse and construction costs during earthquake aftershocks.

A five-parameter constitutive model for hysteresis shearing and energy dissipation of rock joints

Rock joints exhibit hysteresis shearing behavior and produce energy dissipation under shear cyclic loads, which however cannot be accurately depicted by existing constitutive models. This paper establishes a constitutive model for hysteresis shearing and associated energy dissipation of rock joints. Analytical expressions of the model during cyclic shearing processes are derived. Derivation of the model indicates no energy dissipation in the elastic stage. When the shear load exceeds elastic boundary, nonlinear energy dissipation takes place. Validations with experiments show that the proposed model provides good conformities with direct shear curves and hysteresis loops, and can predict the energy dissipation characteristics of rock joints under different working conditions. Compared to the constitutive models using Weibull’s distribution, the proposed one is smooth at the elastic boundary and can accurately capture the maximum shear stress. Unlike the existing incremental-type models, the proposed one provides clear and direct analytical expressions for both shear stress and energy dissipation during the whole displacement domain, which is more convenient in application.

Design optimization of fuzzy controllers in building structures using the crystal structure algorithm (CryStAl)

The current study uses a recently-developed metaheuristic method called Crystal Structure Algorithm (CryStAl) to achieve optimized vibration control in structural engineering. More specifically, this algorithm, which is inspired by the well-established crystallographic principles underlying the formation of crystalline solids in nature, is applied to the optimization of fuzzy logic controllers in building structures. To demonstrate the capability of this method in solving real engineering problems, two real-size building structures, one with three and the other with twenty stories, are considered. The fuzzy controllers are implemented through an active control system to control the seismically-induced vibrations of the structures intelligently. The evaluation criteria utilized to assess the overall performance of the optimization method applied to the fuzzy control system are presented and discussed. Through nonlinear structural analyses, the ductility, energy dissipation, and other nonlinear characteristics of the structures are also considered as the structural responses to be controlled. The computational results obtained from this novel metaheuristic algorithm are compared with those of the other expert systems from the optimization literature. The findings of this paper demonstrate that the Crystal Structure Algorithm is capable of outranking the other methods in the majority of considered cases.

Research on Identification Model of Continuous Compaction Based on Energy Dissipation

A continuous compaction control energy model suitable for contact decoupling between the vibrating wheel and the filling body surface is established through analyzing the energy state of the filling body in the compaction detection stage and calculating nonlinear vibration energy dissipation rate based on the basic principle of continuous compaction control technology and the principle of energy conservation. The significance of the parameters contained in the energy model is analyzed, and the energy index-dissipation measured value (DMV) for evaluating the continuous compaction quality is put forward in combination with engineering practice. The feasibility of DMV is verified, and the applicability of DMV is discussed according to the field test results. The results show that the variation range of the DMV index is about 1.66–2.73 times of the Evd index, the DMV has good repeatability and sensitivity for both coarse-grained and fine-grained filler, and it is less affected by the interference caused by the small fluctuation of mechanical parameters, and has good stability for the local unevenness of filler in horizontal direction. The engineering application shows that the correlation coefficient between energy index DMV and Evd index reach more than 0.87, there is a good correlation between DMV and the conventional quality inspection index Evd, indicating that the energy model is applicable.

Static and Dynamic Mechanical Characterization of Polydimethylsiloxane (PDMS) under Uniaxial Tensile Loading

The present study is based on performing mechanical characterization of polydimethylsiloxane (PDMS) under tensile loading. PDMS samples are developed by mixing prepolymer and curing agent with 10:1 ratio. Mechanical characterization of the PDMS samples is carried out using static and dynamic mechanical testing methods. In particular, the material is characterized under monotonic loading, different strain rates, and force-controlled cyclic loading. The monotonic loading tests are performed at different grip tightening levels to optimize gripping that avoids slipping and reaches failure point. The strain rate dependency and cyclic loading tests are performed to study the viscoelastic behaviour of the material. Strain rate dependency tests are carried out at the strain rates of 6.7×10-3 s-1, 3.2×10-2 s-1, and 6.2×10-2 s-1. The hysteresis tests are performed at the force rates of 0.1 – 2 N/s. The obtained results show that fixing the testing specimen made of soft hyperviscoelastic material such as PDMS is challenging and can significantly affect its stress-strain behaviour and mechanical properties. A higher strain rate increases the stiffness of the material due to the viscoelastic nature of the material. Observing the stress-strain curves, with respect to the lowest strain rate case, the curve for 6.2×10-2 s-1 strain rate diverges at 40% strain compared to 3.2×10-2 s-1 strain rate curve that diverges at 80% strain. The material shows a nonlinear hysteresis behaviour and similar energy dissipation for the considered force-controlled cyclic loading cases.

A proposed method for selecting and scaling recorded seismic accelerations according to TCVN-9386:2012

Accelerogram is a significant input in seismic analysis of structures, particularly for performance-based seismic designs and for advanced technologies using nonlinear energy dissipation devices. However, in seismic regions like Vietnam, earthquake data is generally scarce. Vietnam Standard TCVN-9386:2012 mentions the use of recorded accelerogram for seismic analysis, although it contains shortcomings. The paper aims to detail the procedure of selecting and scaling recorded seismic accelerations according to requirements specified by TCVN-9386:2012. The target response spectrum and the fundamental vibration period of the considered structure are critical factors for the selecting and scaling process. The proposed procedure essentially includes converting the two original horizontal accelerations to the principal directions, correcting the relative proportion between the two acceleration components, determining the period range of interest, calculating the scaling factors, and verifying the 10% matching criteria. An example is conducted on a typical set of accelerations to detail the application of the proposed procedure. The results show that the response spectra of calibrated accelerations are consistent with the target spectrum and satisfy the requirements of TCVN-9386:2012, suggesting that the proposed method can be applied to the seismic analysis of structures with high reliability.

Turbulence-driven magnetic reconnection and the magnetic correlation length: Observations from Magnetospheric Multiscale in Earth's magnetosheath

Turbulent plasmas generate a multitude of thin current structures that can be sites for magnetic reconnection. The Magnetospheric Multiscale (MMS) mission has recently enabled the detailed examination of such turbulent current structures in Earth's magnetosheath and revealed that a novel type of reconnection, known as electron-only reconnection, can occur. In electron-only reconnection, ions do not have enough space to couple to the newly reconnected magnetic fields, suppressing ion jet formation and resulting in thinner sub-proton-scale current structures with faster super-Alfvénic electron jets. In this study, MMS observations are used to examine how the magnetic correlation length (λC) of the turbulence, which characterizes the size of the large-scale magnetic structures and constrains the length of the current sheets formed, influences the nature of turbulence-driven reconnection. We systematically identify 256 reconnection events across 60 intervals of magnetosheath turbulence. Most events do not appear to have ion jets; however, 18 events are identified with ion jets that are at least partially coupled to the reconnected magnetic field. The current sheet thickness and electron jet speed have a weak anti-correlation, with faster electron jets at thinner current sheets. When λC≲20 ion inertial lengths, as is typical near the sub-solar magnetosheath, a tendency for thinner current sheets and potentially faster electron jets is present. The results are consistent with electron-only reconnection being more prevalent for turbulent plasmas with relatively short λC and may be relevant to the nonlinear dynamics and energy dissipation in turbulent plasmas.

The fracture failure of three-dimensional concrete structures subjected to concentrated loadings using the Boundary Element Method

Abstract This study applies the Boundary Element Method (BEM) for the fracture failure modelling of three-dimensional concrete structures subjected to concentrated boundary conditions. The non-requirement of domain mesh by the BEM enables high accuracy in the domain fields assessment in addition to less complex remeshing procedures during crack propagation. However, concentrated boundary conditions often occur in fracture mechanics. The Lagrangian version of the BEM enforces such boundary conditions approximately by small length elements, which lead to numerical instabilities or even inaccurate problem representation. This study proposes a formulation for representing properly concentrated boundary conditions within the Lagrangian BEM framework. Nonlinear fracture mechanics describes the material failure processes herein. The classical cohesive crack approach governs the nonlinear energy dissipation processes, in which constant and tangent operators solve the resulting nonlinear system. Three applications demonstrate the accuracy of the proposed formulation, in which the BEM responses are compared against numerical and experimental results available in the literature.

Response of Jointed Structures in Shock-Induced Flow: Surface Pressure and Structural Measurements with Finite Element Modeling

Experiments, modeling, and simulation were used to study the nonlinear dynamics of a jointed structure in a shock tube. The structure was a full-span square cylinder with internal bolted connections excited by fluid loading. The Reynolds number based on width was . The cylinder was exposed to an impulsive force associated with the incident shock followed by transverse loading imposed by vortex shedding. Experimentally, aerodynamic loading was characterized with high-speed pressure sensitive paint (PSP). Digital image correlation concurrently measured the structural response. Maximum displacement occurred when the vortex shedding frequency most closely matched the structural mode of the beam associated with a rocking motion at the joint. A finite element model was developed using Abaqus, where Coulomb friction modeled the nonlinear contact in the joint. The PSP data supplied the input load to the model as a one-way-coupled interaction. The simulations matched well the trends observed in the experiment. Overall, the root-mean-square values of the transverse displacement agreed to within 24% of the experiment. The modeling showed rocking about the joint during vortex shedding was critical to the nonlinear damping and energy dissipation observed in the structure. This highlights the importance of jointed connections to energy dissipation in structures under aerodynamic loading.