Damping Capacity Research Articles

Superior damping capacity of a C-containing FCC medium-entropy alloy

Construction machinery noise not only affects its service life, but also brings hazards to people's physical and mental health. Achieving a high and stable internal friction characteristic to eliminate noise and mechanical vibrations is always the desired goal in the design of damping alloys. In the study, we present a C-containing Fe-Mn-Cr-Ni medium entropy alloy that exhibits a superior damping capacity with an internal friction peak value of 0.083. The Finkelstein-Rosin relaxation peak appears at 550 K in the internal friction spectrum, which is attributed to the reorientation of C-C pairs and C substitutional atom pairs under stress, with the diffusion activation energy are 155.172 kJ·mol−1 and 166.711 kJ·mol−1, respectively. The relaxation of Finkelstein-Rosin peak enhances the damping capacity of the alloy, which provides an effective method for regulating the damping properties of medium entropy alloys.

Adjustable damping properties of the AlCrFe2Nix medium entropy alloys by tuning phase constituent

The effects of Ni content on the phase constituent, mechanical properties and damping capacity of the AlCrFe2Nix (x = 1.0, 1.5, 1.7, 2.1, 2.2 and 2.3) medium entropy alloys (MEAs) were studied. When x = 2.1, the microstructure of the MEA consists of BCC phase as the matrix and FCC phase as the second phase with the corresponding volume fractions of 87.7, 12.3 vol%, respectively. The combination of hard BCC matrix and soft FCC secondary phase, especially, the BCC phase is isolated by the circular FCC phase, results in a very high damping capacity up to 0.06936 for the AlCrFe2Ni2.1 MEA at the corresponding strain amplitude of 2.55 × 10−4. Both the BCC matrix and the peculiar microstructure play a key role in increasing the damping capacity of the AlCrFe2Ni2.1 MEA. Excellent damping performance and comprehensive tensile properties of AlCrFe2Ni2.1 MEA indicate that it has potential applications as the candidate of damping materials.

Input Energy Reduction‐Oriented Control and Analytical Design of Inerter‐Enabled Isolators for Large‐Span Structures

Seismic isolation technologies for large‐span structures have rapidly developed alongside the popularization of the seismic resilience concept. To produce a high‐efficiency isolation technology with lower energy dissipation demands, this paper proposes a novel inerter‐enabled isolator (IeI) and a tailored input energy reduction‐oriented design method. The inerter‐based damper within the IeI is developed by combining the dashpot, tuning spring, and two inerters to facilitate the optimization of inerter distribution. Assuming the large‐span structure remains linear, the overall seismic input energy of the large‐span structure with IeIs and its allocation in the superstructure and additional damping are quantified using stochastic energy analysis. The advantages of the IeI over the conventional linear viscous damper (LVD) isolator are elucidated through dimensionless parametric analysis. Based on the results of parametric analysis, an input energy reduction‐oriented design method is proposed for the IeI, along with an easy‐to‐follow diagram that helps with preliminary design in practical applications. The effectiveness of the IeI and the proposed design method is validated through a design case study of a benchmark large‐span structure. The results demonstrate that the IeI reduces the seismic response of large‐span structures by simultaneously employing the input energy reduction effect of grounded inerters with the damping‐enhancing effect of inerter‐based dampers. The proposed design method effectively balances the performance of controlling the large‐span structure and the isolator displacement. Under consistent control performance and isolator displacement constraints, the IeI requires much less damping coefficient and energy dissipation capacity than the conventional LVD isolator. Moreover, leveraging the damping enhancement and input energy reduction effects, the IeI achieves comparable control performance to the conventional LVD isolator, even under stricter isolator displacement constraints.

A Review on Composite Material Reinforced With Natural Fibers

Abstract: Materials plays vital role for survival of any manufacturing industry. Conventional materials are replaced by composite material because of their high specific strength, strong damping capacity and high specific modulus. In modern era, natural fiber reinforced polymer composites came into light because of promising properties of natural fibers such as light weight, water resistance, high impact strength, environment friendly etc. In this study, different types of natural fibers that can be used as reinforcement in polymer composite are discussed. Various methods of production and steps involved in processing of natural fiber reinforced composite are presented. Then, mechanical and tribological properties of these composites are reviewed and presented. The different applications of natural fiber reinforced polymer composite are also discussed.

PROCEDURE FOR DESIGN OF DOWNHOLE DAMPING DEVICES USING ELASTOMERS

The article is devoted to the problem of combating vibration and shock loads in the oil production industry. Described is a method of reducing loads due to the use of dampers in the design of devices. It is indicated that for damping vibration loads in mechanical engineering a wide range of design solutions is used using hydraulic, pneumatic and mechanical systems and devices. The article compares the use of springs and elastomers as a damping element in mechanical structures of downhole devices. It is also indicated that it is recommended to use experimentally obtained dependencies to select the damping material of the elastomer: with vibration of forced vibrations from 13.5 to 23.5 Hz, the density of the material should be increased, and with forced vibrations from 25 to 50 Hz, on the contrary, the density of the material should be reduced.As a vibration-isolated object, the article considers the installations of electrically driven centrifugal pumps (ESP), in which, due to unstable operating conditions, modules are often divided with a fall («flight») at the bottomhole due to fatigue destruction of the connecting elements. Two patented structural solutions to combat vibration and impact loads due to inclusion of a damping module with an elastomer substrate made in one case with an external conical surface and in the other in the form of a cylindrical bushing are presented.In recent years, there has been a trend towards a decrease in the diameter of wells and, accordingly, casing pipes. Therefore, an ESP arrangement with a damping module with a substrate made in the form of a cylindrical sleeve is most acceptable. Since in this design it is possible to increase the damping capacity of the module by increasing the thickness of its substrate.For this damper design, a method for calculating the relative longitudinal compression strain of its elastic substrate has been developed. It is shown that in order to ensure radial extension of levers by the required value, it is necessary and sufficient to determine the maximum diameter of the deformed (compressed) cylindrical rubber bushing, which at the same time acquires a barrel-like shape with a curvature of the generatrix depending on the rubber material: density and tightening factor.

Experimental study and predictive modelling of damping ratio in hybrid polymer concrete

The improved damping capacity of concrete materials is crucial for many applications, especially the ones exposed to dynamic external forces. This study explores the optimal circumstances of copolymer composite binder, ratio of fine to coarse aggregate, curing time, size and content of tyre crumb rubber on enhancing damping ratio of hybrid polymer concrete. Owing to the limitation of conventional models and experimental methods in effectively handling the multiple and complicated relationship between the input parameters of the hybrid polymer concrete and its damping capacity, two robust machine leaning models including extreme gradient boosting (XGB), and artificial neural network (ANN) algorithms were developed to predict the values of damping ratio from an experimental database of 196 samples. Multiple linear regression (MLR) was employed in this study as a benchmark for comparing with the ANN and XGB methods. The results indicate that the considered algorithms yield accurate models for predicting the damping ratio of HPC composites. However, ANN and XGB outperform MLR with an impressive R-square of 0.985 and 0.981, respectively versus 0.875. Analysing the importance of input features using the XGB algorithm also reveals that the curing time has the highest impact on predicting the damping ratio. The volume fractions of resin matrix and crumb rubber are the next most important features. The crumb rubber size, within the studied range, appears to be the least impactful one.

Kutu Sementasyon Tekniğiyle GGG70 Küresel Grafitli Dökme Demir Yüzeyine Kaplanan NbC Tabakasının Özelliklerine Kaplama Sıcaklığın Etkisin İncelenmesi

Nodular Graphite Cast Irons stand out with their high castability, high strength, vibration damping and high loading capacity. With today's technologies, the surface properties of materials can be improved by coating them with various methods and high-performance engineering materials can be obtained. Pack Cementation Technique is preferred among coating methods due to its relatively lower cost and applicability. In this study, it was aimed to coat NbC on the surface of GGG70 Nodular Graphite Cast Iron using the Pack Cementation Technique at 900 °C, 1000 °C and 1100 °C for 6 hours. The effect of temperature on the properties of the resulting coating layers was investigated. For this purpose, the surface morphologies of the samples were examined and their fracture toughness and hardness values were obtained. Coating morphologies were examined by XRD, optical microscope and SEM analysis and changes in coating structure and thickness were obtained. When the results were examined, it was determined that the coating thickness increased with the increase in coating temperature. Accordingly, it was observed that the fracture toughness value of the coatings first increased and then decreased slightly. Microhardness values increased approximately 5 times in the coating areas.

The influence of particle shape on crushing pattern and energy dissipation within a pressurized sand damper

A discrete element method (DEM) model was introduced to examine the crushing pattern, energy dissipation, force–displacement curves, and stresses within a pressurized sand damper (PSD). Simulations were carried out with various particle shapes, including elongated, triangle, pyramid, cube, and hexagon. While monitoring the force–displacement curves, it was observed that the hexagon-shaped particles yielded the highest forces, while the triangle-shaped particles resulted in the lowest forces. Altering the particle shapes did not significantly impact the overall shape of the force–displacement curves, suggesting that dynamic force generation remains unaffected by the particle shape. Particle crushing was closely examined for all particle shapes, and it was concluded that all shapes exhibit relatively similar crushing locations and patterns. In the analysis of normal stress, hexagon- and elongated-shaped particles were found to experience the highest and lowest stresses, respectively. Observing the energy dissipation revealed that, among the shapes studied, triangle-shaped particles had the lowest cumulative dissipated energy over five loading-unloading cycles, whereas hexagon-shaped particles had the highest. The calculation of specific damping capacity showed a large loss angle, indicating the presence of large strains inside the model.

Role of geometrically necessary dislocations on the superior damping capacity and high strength-ductility of 5083Al/SUS405 laminated heterostructure composites

The laminated heterostructure composite design was implemented on 5083Al alloy. Through the process of vacuum hot pressing (HP state) followed by cold rolling and annealing (CRA state), the 5083Al/SUS405 laminated heterostructure composites (LHCs) were fabricated. The LHCs exhibit excellent combination of strength-ductility and damping capacity. The damping in the LHCs originates from the combined effects of dislocation, interface and ferromagnetic damping mechanisms. Compared to 5083Al alloy, the LHCs exhibit higher dislocation damping at relatively high strain amplitudes (ε > 0.01 %), especially for the CRA state LHC with higher density of geometrically necessary dislocations (GNDs). This suggests that GNDs not only enhance strength-ductility through the hetero-deformation induced (HDI) hardening effect, but also contribute to dislocation damping in the LHCs.

A ZA22/Al interpenetrating phase composite with high compressive stress plateau and high damping capacity

A ZA22/Al interpenetrating phase composite (IPC) was prepared by a two-step infiltration method for the first time. The ZA22 alloy and the Al matrix were well bonded together, and a layer with ultrafine grains containing Al, Zn and O elements was formed between them. Lamellar eutectoid structure (LES) in original ZA22 alloy transformed to granular eutectoid structure (GES) with submicron sized α and η phases, resulting in a significant increase in phase interface density. The property test results showed that the IPC has a high compressive stress plateau and a high damping capacity up to 0.2. Correlated mechanisms were discussed.

An experimental study for effectiveness of steel fibre reinforced exterior beam-column joints under cyclic resistance

An ability of the structure to sustain levels of inelastic deformation, implicit in ductility values, is dependent on the material and detailing used. In order to achieve this high percentage of lateral reinforcement in the core of the joint is needed; which lead to reinforcement congestion and construction difficulties. In this paper, the behaviour of beam-column joint was investigated for different variations in spacing of lateral reinforcement in critical region. This increased spacing of lateral hoops reduced the reinforcement conjunction and addition of steel fibre reinforced concrete (SFRC) for same region help to remove deficiency due to removal of lateral reinforcement. The steel fibre volume fraction of 2% was used in critical region. Test results of six one-third scaled beams-column joints of reinforce concrete frame are presented to study the influence of steel fibres for effective reduction of lateral hoops in joint region. The experimental investigations also incorporate the evaluation of parameters such as ultimate strength, energy dissipation, ductility, stiffness, specific damping capacity and crack patterns. An experimental result demonstrated that SFRC beam-column joint perform satisfactorily and showed enhancement in all above properties. The behaviour of beam-column joint also showed that the additions of fibre in critical region provided necessary confinement and ductility after reduction in lateral hoops.

Effect of Al element on microstructure, mechanical properties and damping capacity of LPSO-containing Mg-Y-Zn-Li alloy

A novel LPSO containing Mg-5Y-2n-2Li-0.5Al alloy with superior mechanical behaviors and damping capacities was first developed in this paper. The microstructure evolution, mechanical and damping properties of Mg-5Y-2n-2Li-0.5Al alloy were analyzed and compared with those of Mg-5Y-2Zn-2Li alloy. The results indicated the extruded Mg-5Y-2n-2Li-0.5Al alloy exhibited bimodal grain structure, including fine dynamically recrystallized grains (DRXed grains) and coarse un-dynamically recrystallized (unDRXed) grains, accompanied by the produce of the 14H LPSO phase, Al3(Y, Zn) particle and nano-precipitates AlLi phase. Due to the strengthening effects of grain boundary, residual dislocation and precipitation, the ultimate tensile strength (UTS), tension yield strength (TYS) and elongation (EL) of the extruded Mg-5Y-2Zn-2Li-0.5Al alloy were 312 MPa, 229 MPa and 10.9%, respectively, which were higher than that those of the extruded Mg-5Y-2Zn-2Li alloy. In addition, the extruded Mg-5Y-2Zn-2Li-0.5Al alloy displayed good damping capacities at both room and high temperature (RT and HT), and its RT damping value (Q−1) at 5 × 10−4 strain amplitude exceeded 0.01, which associated with a high density of movable dislocation. With rising the temperature, the extruded Mg-5Y-2n-2Li-0.5Al alloy possessed superior damping properties than the Al-free alloy, which derived from the grain boundary slide (GBS) and the activation of the incoherent interface between the Al3(Y, Zn) and α-Mg phase after adding Al element.

Development of High-Entropy Shape-Memory Alloys: Structure and Properties

Amongst functional materials, shape-memory alloys occupy a special place. Discovered in the beginning of 1960th in XX century, these alloys attracted quite an attention because of the possibility to restore significant deformation amounts at certain stress–temperature conditions due to the martensitic diffusionless phase transformation involved in a process. It was possible to exploit not only so-called ‘shape-memory’ effect, but also superelasticity and high damping capacity. Over the years, more than 10 000 patents on shape-memory alloys were filed, appreciating not only the possibility to exploit energy transformation to ensure the response (feedback) at the change in independent thermodynamic parameters (temperature, stress, pressure, electric or magnetic field, etc.), but the significant work output as well. Applications ranged from different gadgets to automotive, aerospace industries, machine building, civil construction, etc. Unfortunately, the structural and functional fatigue restricted successful business application to medical sector with nitinol shape-memory alloy (different implants, stents, cardiovascular valves, etc.). Emerging high-entropy shape-memory alloys can be considered as a chance to overcome fatigue problems of existing industrial shape-memory alloys due to their specific structure that ensures superior resistance to irreversible plastic deformation.

Experimental and Numerical Investigation of the Damping Performance of Metal Additively Manufactured Particle Damper

The additively manufactured particle damper (AMPD) is a novel particle damper fabricated by leaving unfused powder inside the pre-designed structural cavities during the laser powder bed fusion (LPBF) process. It can be applied at high temperatures and a wide range of frequencies without any additional installation space. However, the damping mechanism and performance of AMPD are still unclear due to insufficient experimental and simulation analyses. In this work, the damping capacity of AMPDs with three different unit cell sizes at high frequencies and low vibration amplitudes were investigated experimentally and numerically. The AMPDs were manufactured using LPBD with 316 L stainless steel. The complex power method was used to measure the energy dissipation of the AMPD directly. A discrete element method (DEM) simulation model was developed to visualize the particle motion mode during each vibration process. The computed tomography (CT) pictures were utilized to measure the powder distribution in each AMPD's cavity. Finally, the influence of excitation frequency, excitation amplitude, and cavity size on the damping performance of the AMPD were explained by comparing the experimental and simulation results.

Probing the varying ranges of damping capacity of magnesium alloys containing long-period stacking ordered phases

Traditional high damping Mg alloys, based on the concept of purified matrix, cannot withstand large vibrational strain, inhibiting their practical use. The current study employed Mg alloys containing long-period stacking ordered (LPSO) phase and designed representative microstructures, to probe the varying ranges of damping capacity. It is found that intragranular LPSO lamellae effectively purify the matrix without hindering dislocation vibrations, hence contribute to improving damping capacity at small strain. They also provide additional boost to damping capacity at intermediate strain. Precipitates, as matrix purifiers, are detrimental to damping capacity. Quantitative analyses of damping curves and the correlation with stress-strain data reveal that the transition to the rapidly rising part on damping curves physically corresponds to plastic yielding. This further inspired two perspectives of viewing damping capacity at the characteristic strain values of different materials, representing a paradigm shift of material selection and providing a rational criterion for future alloy development.

Compression performance and low-frequency damping characteristics of pyramidal lattice cylinder skeleton structure

The lattice structure has obvious advantages over traditional materials in terms of light weight, energy absorption, vibration and noise reduction, and is therefore widely used in many fields such as shipping and aerospace. In this work, a cylinder skeleton structure is designed based on pyramidal lattice structure by circumferential and axial array arrangement. The load-bearing capacity of the pyramidal lattice cylinder skeleton structure under quasi-static compression and its axial vibration characteristics are investigated by numerical method. The effects of key element geometric parameters such as diameter of metal wire, circumferential angle and axial angle on the compression and vibration damping performances of the pyramidal lattice cylinder skeleton structure were investigated. The results show that the developed structure has excellent compression and vibration damping capacity. It is able to provide a pronounced damping effect in the low-frequency range of 204-367 Hz, and the attenuation intensity of elastic wave in this frequency range can be up to 20dB.

Compression and resilient behavior of graded triply periodic minimal surface structures with soft materials fabricated by fused filament fabrication

Additive manufacturing is an effective method to realize complex biomimetic topology and tunable mechanical property. In the current work, to meet the requirements of damping buffers and energy absorbers, triply periodic minimal surface (TPMS) structure using two soft polymeric blends as feedstock materials were gradient design and manufactured via fused filament fabrication. The internal topography of Schwarz P, Gyroid and Diamond TPMS structures were observed by scanning electron microscope and micro-computed topography. The compressive test results demonstrated that Diamond possessed superior load-carrying and energy absorption capacity to Gyroid and Schwarz P structure. The energy absorption for graded Diamond and Gyroid structures were better than the uniform controls, whereas Schwarz P displayed an opposite trend. Meanwhile, less internal damage and good resilient behavior were observed for polymeric blends with better resistance to plastic deformation. Lastly, cycle loadings were conducted, and the elastic energy, consumed energy as well as the specific damping capacity for graded and uniform TPMS soft structures were explored. With the increase of loading cycles, the Diamond TPMS structure exhibited a better damping behavior whereas Schwarz P displayed an elastic behavior. The elastic deformation was gradually replaced by the inelastic deformation of energy consumption and dissipation.

High magneto-mechanical hysteresis-type damping in FeGaMo alloys

Optimization of the damping capacity of conventional FeCr-based ferromagnetic high damping alloys (HDAs) usually involves a trade-off in terms of degradation of mechanical properties due to grain coarsening caused by high-temperature annealing. In this work, new ferromagnetic HDAs of FeGaMo alloys with different Mo contents are reported, which can exhibit high damping when treated in a medium temperature range. Among these alloys, the alloy with Mo content of 2 at% exhibits the best damping capacity of 4.20 × 10−2 (Q−1, equivalent to a special damping capacity SDC of 0.26). It is found that the Mo element has a high solid solubility in the FeGa alloy, and when the Mo content is 2 at%, only isolated tiny precipitations are observed in the matrix. These small precipitates have a negligible effect on hindering domain motion, and the corresponding coercivity change is extremely weak compared to the Mo-free FeGa alloy. As the Mo content increases to 4 at% or 6 at%, Mo-rich phases precipitate within the grains and along the grain boundaries, resulting in an increasing coercivity. Interestingly, as the Mo content increases, the domain density in the (001) and (110) surfaces gradually increases and the arrangement of magnetic domains becomes more tortuous due to the decrease in the magnetocrystalline anisotropy constant. For the FeGaMo alloy with 2 at% Mo content, the high damping capacity mainly arises from the energy loss caused by the high density of irreversible motion of domain walls (DWs) under the applied stress, and as the Mo content continues to increase, the significant precipitation of Mo-rich phases severely restricts the movement distance of DWs, leading to a decrease in damping. This work provides valuable insights for the design and research of new ferromagnetic high damping materials in the future.

Microstructure, Corrosion and Mechanical Properties of Magnesium Alloys

The properties of magnesium (Mg) and its alloys such as uniquely high specific strength (strength-to-density ratio), good castability, excellent machinability, adequate high-temperature formability and high damping capacity have garnered significant interest from researchers and product designers, especially in the automotive and aerospace industries, for many years [...]

Carbon Nano-Onions as Nanofillers for Enhancing the Damping Capacity of Titanium and Fiber-Reinforced Titanium: A Numerical Investigation

Improving the damping capacity of metal matrix composites is crucial, especially for applications in the aerospace industry where reliable performance against vibrations and shocks is mandatory. The main objective of the present study is the numerical prediction of the damping behavior of alpha titanium matrix nanocomposites reinforced with hollow carbon nano-onions at various volume fractions. According to the proposed numerical scheme, a structural transient analysis is implemented using the implicit finite element method (FEM). The metal matrix nanocomposites are modeled via the utilization of appropriate representative volume elements. To estimate the mechanical and damping behavior of the nanocomposite representative volume elements, axial sinusoidally time-varying loads are applied to them. The damping capacity of the metal matrix nanocomposites is then estimated by the arisen loss factor, or equivalently the tan delta, which is computed by the time delay between the input stress and output strain. The analysis shows that the loss factor of alpha titanium may be improved up to 60% at 100 Hz by adding 5 wt% carbon nano-onions. The numerical outcome regarding the dynamic properties of the carbon nano-onions/alpha titanium nanocomposites is used in a second-level analysis to numerically predict their damping performance when they are additionally reinforced with unidirectional carbon fibers, using corresponding representative volume elements and time-varying loadings along the effective direction. Good agreement between the proposed computational and other experimental predictions are observed regarding the stiffness behavior of the investigated metal matrix nanocomposites with respect to the mass fraction of the carbon-onion nanofillers in the titanium matrix.