Composite Damping Research Articles

Optimization of Dynamic Characteristics of Rubber-Based SMA Composite Dampers Using Multi-Body Dynamics and Response Surface Methodology

The suspension system of a commercial vehicle cab plays a crucial role in enhancing ride comfort by mitigating vibrations. However, conventional rubber suspension systems have relatively fixed stiffness and damping properties, rendering them inflexible to load variations and resulting in suboptimal ride comfort under extreme road conditions. Shape memory alloys (SMAs) represent an innovative class of intelligent materials characterized by superelasticity, shape memory effects, and high damping properties. Recent advancements in materials science and engineering technology have focused on rubber-based SMA composite dampers due to their adjustable stiffness and damping through temperature or strain rate. This paper investigates how various structural parameters affect the stiffness and damping characteristics of sleeve-type rubber-based SMA composite vibration dampers. We developed a six-degree-of-freedom vibration differential equation and an Adams multi-body dynamics model for the rubber-based SMA suspension system in commercial vehicle cabins. We validated the model’s reliability through theoretical analysis and simulation comparisons. To achieve a 45% increase in stiffness and a 64.5% increase in damping, we optimized the suspension system’s z-axis stiffness and damping parameters under different operating conditions. This optimization aimed to minimize the z-axis vibration acceleration at the driver’s seat. We employed response surface methodology to design the composite shock absorber structure and then conducted a comparative analysis of the vibration reduction performance of the optimized front and rear suspension systems. This study provides significant theoretical foundations and practical guidelines for enhancing the performance of commercial vehicle cab suspension systems.

Progress on the Sound Absorption of Viscoelastic Damping Porous Polymer Composites.

Porous polymer composites (PPC) have developed rapidly recently, which are widely used in various industrial fields. Viscoelastic damping is an important behavior of porous polymer composites, and it can determine the sound absorption for noise reduction applications. This review has mainly covered the viscoelastic damping and sound absorption of porous polymer composites. Different fabrication approaches of porous polymer composites are gathered. The mechanism of viscoelastic damping behavior is described, and also the sound absorption properties. Followed by the introduction of enhanced sound absorption of viscoelastic damping porous polymer composites, including the incorporation of fillers, microstructures modification, combination with nanofibrous materials, and multilayer configuration, etc. The incorporated fillers can effectively adjust the interfacial area in composites, and obtain desired bonding conditions. Microstructures modification is an effective tool to improve the morphologies of both polymer matrix and fillers, which can be achieved by chemical treatment and surface coating. The combination with lightweight nanofibrous layer can increase the low frequency absorption. The configuration of multilayer composites can improve both acoustical and mechanical properties for engineering applications. It is hoped that this comprehensive review is benefit for the promising development of porous polymer composites in related fields.

The Stiffness and Damping Characteristics of a Rubber-Based SMA Composite Shock Absorber with a Hyper-Elastic SMA-Constitutive Model Considering the Loading Rate.

Shock absorbers are essential in enhancing vehicle ride comfort by mitigating vibrations. However, traditional rubber shock absorbers are constrained by their fixed stiffness and damping properties, limiting their adaptability to varying loads and thus affecting the ride comfort, especially under extreme road conditions. Shape Memory Alloys (SMAs), known for their intelligent material properties, offer a unique solution by adjusting stiffness and damping in response to temperature changes or strain rates, making them ideal for advanced vibration control applications. This study builds upon the Auricchio constitutive model to propose an enhanced SMA hyper-elastic constitutive model that accounts for different loading rates. This new model elucidates the impact of loading rates on the stiffness and damping characteristics of SMAs. Additionally, we introduce an innovative circular rubber-based SMA composite vibration reduction structure. Through a parameterized model and finite element simulation, we comprehensively analyze the stiffness and damping properties of the composite damper under various loading rates and harmonic excitations. Our findings suggest a novel approach to improving the vehicle ride comfort, offering significant potential for engineering applications and practical value.

Influence of chemical treatment of Bamboo fibers on the vibration and acoustic characterization of Carbon/Bamboo fiber reinforced hybrid composites

In the pursuit of sustainable materials, natural fibers are gaining attention because of their renewable nature and low environmental impact. However, their application in composites has been hindered by their hydrophilicity and non-homogeneity in the properties. To address these issues, chemical treatments such as Sodium Hydroxide and Potassium Permanganate have been utilized. This study explored the impact of chemical treatments on Bamboo fibers and their subsequent influence on the vibration and acoustic properties of Carbon/Bamboo fiber-reinforced hybrid composites. This study investigates the vibration damping and acoustic characteristics of hybrid composites, considering the synergistic advantages of Bamboo’s natural damping properties and Carbon fiber’s mechanical strength. The damping factor of Sodium Hydroxide treated Bamboo fiber reinforced hybrid composites is 34.55% higher than that of untreated Bamboo fiber reinforced hybrid composites. It is also 11.95% higher than that of Potassium Permanganate treated Bamboo fiber reinforced hybrid composites. The flexural modulus of untreated Bamboo fiber reinforced hybrid composites was 164.36% and 157.77% higher than that of Sodium Hydroxide treated and Potassium Permanganate treated Bamboo fiber reinforced hybrid composites, respectively. The effect of chemical treatment on the fiber properties were analysed using the FTIR spectrum. Acoustic characterization revealed that untreated Bamboo fiber composites have higher sound absorption coefficients at lower frequencies, whereas Sodium Hydroxide-treated composites have higher sound absorption coefficients at medium and high frequencies. The results indicated that chemical treatment enhanced fiber-matrix adhesion, reduced stiffness, and influenced the damping and acoustic performance of the hybrid composites.

Mechanical, vibration damping and acoustics characteristics of hybrid aloe vera /jute/polyester composites

The development of biodegradable hybrid fibre composites is gaining pace in the automotive and construction industries due to their lightweight structural applications, which offer considerable benefits for the environment. In this present investigation, hybrid bio composites were fabricated using a compression molding machine with plain woven jute and aloe vera mats along with polyester resin as the matrix. Six types of hybrid biocomposite laminates were prepared by varying the stacking arrangement of jute and aloe-vera mats to analyse the impact of stacking arrangements on vibration damping and acoustic behaviour of these hybrid bio composites. From the results, it is concluded that the maximum value of natural frequency is obtained from the JJAJ type of composite. i.e., 157, 326, and 370 Hz for Modes I, II, and III respectively, due to good interlacing of fibres in the weft and warp directions. J/J/A/J (AJ3) hybrid bio composite has highest sound absorption coefficient of 0.47 at 3000 Hz, and a better transmission loss i.e 19.84 dB, according to the results of the acoustic research. The comparison of experimental and theoretical analysis was carried out, and found that experimental and theoretical values are closely related to each other.

Dynamic modeling and parametric instability analysis of internally damped rotating composite shafts in inertial and rotating frames

Parametric resonance may occur when the composite shaft is subjected to periodic axial loads. The phenomenon will lead to the serious destruction of the dynamic system. In this study, we aim to investigate the parametric instability characteristics of rotating composite shafts considering internal damping, and to provide valuable theoretical guidelines for avoiding the occurrence of parametric resonance. The two dynamic models of the composite rotor in the inertial frame and rotating frame are both established using Hamilton's principle. The governing equations of the composite rotor are reduced into a system of Mathieu–Hill equations by means of the Galerkin method. Then Floquet exponent method is employed to conduct parametric stability analysis of the periodic loaded composite rotor. After performing validation of present model and method, numerical results are presented to bring out the influences of reference frame, rotation speed, internal damping and lamination angle on the parametric instability region. The results show that the selection of reference frame does not affect the determination of the size and type of the parametric instability region. However, it is more suitable to use the rotating frame from the perspective of determining the type of the unstable region. The internal damping of composites should not be ignored when analyzing the parametric stability of composite rotors, especially for the high order excitation frequency.

A low-density polymer/CrMnFeCoNi composite with high strength and high damping capacity

A novel damping composite was successfully prepared by taking a porous CrMnFeCoNi high-entropy shape memory alloy as the skeleton and filling its pores with the composite composed of carbon nanotubes and polyurethane/epoxy interpenetrating polymer networks. When the porosity, pore size and CNT loading are 80 %, 1.2 mm and 2 wt%, respectively, the compressive strength, elastic modulus and energy absorption capacity of the composite are 35.7 MPa, 1.31 GPa and 23.1 MJ/m3 (ε = 65 %), respectively. Furthermore, it has a mere density of 2.525 g/cm3. Its loss factor is greater than 0.093 and can reach a maximum of 0.145 within the temperature and frequency range of 20 ∼ 150 ℃ and 0.1 ∼ 200 Hz. A triple-phase micromechanical model was utilized to explore the damping mechanism of composites. Results indicate the coupling of multiple damping mechanisms is the reason for the high ground-state damping of composites, and interface damping is the primary damping mechanism. The superposition of the ε → γ reverse martensite transformation peak of the CrMnFeCoNi HESMA skeleton and the glass transition peak of the CNTs/polymer composite matrix realizes the wide damping temperature range of the composite.

Assessment of damping and flexural behaviour of hybrid fibre-particulate composites

Hybrid composites are an advanced solution that offers multifunctional capabilities, including exceptional strength-to-weight ratios, vibrational damping and impact absorption. This work describes the damping capacity and flexural behaviour of a hybrid fibrous-particulate system composed of glass/carbon fabrics and three distinct micro-inclusions: silica particles, carbon waste microfibres, and cement. A statistical methodology based on the full factorial design is applied to identify the effects of fibre stacking sequence, including carbon-C5, glass-G5, C2G3, G3C2, GCGCG and CG3C, microparticle inclusions and matrix/fibre volume fraction (40/60 and 60/40) on damping and bending responses. A non-linear finite element (FE) analysis is conducted to explore the stress distribution based on the stacking sequence and predict the failure mechanisms of the hybrid laminate. The results indicate significant interaction effects, with hybrid architectures showcasing approximately 33% higher performance compared to glass fibre composites. A greater dependence on the fibre layup sequence is found for the damping factor, flexural modulus and strength. Notably, the incorporation of silica microparticles leads to an increase in flexural strength. Furthermore, a greater volume fraction of the matrix phase enhances the rheological efficiency in terms of the fibre-particle interface. Carbon fibre layers placed symmetrically on both beam sides (CG3C) and bottom layers (G3C2) significantly enhance the bending performance of hybrid composites.

Interface Optimizing Core-Shell PZT@Carbon/Polyurethane Composites with Enhanced Passive Piezoelectric Vibration Damping Performance.

Presently, piezoelectric materials are gradually playing a significant role within composites to improve the damping and vibrational attenuation capacities of host composites. Previous studies paid attention to isolating the mechanical damping contribution and piezoelectric contribution of polymer-based piezoelectric composites (PPCs). However, reports detailing the piezoelectric damping of such materials have not paid sufficient attention to the technologies and methods to improve the piezoelectric damping of PPCs. In this study, we propose novel damping polyurethane (PU)-based piezoelectric composites with carbon-coated piezoelectric fillers (PZT@C/PU) with improved piezoelectric damping ability. The mechanical damping and piezoelectric damping of composites were theoretically decoupled, and we elaborate on the mechanism enhancing piezoelectric damping through the carbon coating strategy by comparing with the composites with nonpiezoelectric fillers. The as-fabricated core-shell structure having an optimized interface exhibits the proposed PZT@C/PU composite pads with relatively prominent damping ability (loss factor tan δmax = 1.0, tan δRT = 0.3), ductility (400.63%), and sound isolating behavior (transmission loss TL > 23 dB). Moreover, the vibration test results of as-fabricated sandwich structural PZT@C/PU composite damping devices exhibit outstanding vibration attenuating behavior (damping ratio ζ = 0.198). The study herein validates that the carbon shell coated on piezoelectric fillers would effectively increase damping performance of PU-based piezoelectric composites by the enhancement of piezoelectric performance caused by carbon coating piezoelectric fillers, which indicates that this material has potential for future applications in the field of vibration and noise reduction, thereby driving forward and expanding the fundamental understanding in the area of PPCs damping and vibration attenuation.

Effect of Hydrothermal Aging on Damping Properties in Sisal Mat-Reinforced Polyester Composites.

Hydrothermal aging is a matter of considerable concern for natural fiber-reinforced polymers; it can alter dimensional stability and induce microcracks and macro strain on the composite structure. This study applied a sorption kinetic model and examined the effects of water on the damping factor of sisal mat-reinforced polyester composites. The experimental data were fitted well using a Boltzmann sigmoid function, suggesting a promising first step toward kinetic water sorption modeling. Additionally, a damping test was carried out using the impulse excitation technique, highlighting the composite material's dynamic response under varying water absorption conditions. The result showed that damping exhibited sensitivity to water absorption, increasing significantly during the first 24 h of immersion in water, then remained steady over time, inferring a critical time interval. An empirical model proved satisfactory with the correlation coefficient for sorption rates and damping of sisal mat polymeric composites.

A Novel Viscoelastic-Friction Model for the Multiphase Hysteretic Behavior of Aluminum Foam/Polyurethane Interpenetrating Phase Composite Damper

An aluminum foam/polyurethane interpenetrating phase composite damper (AF/ PUCD) can perform multi-functional energy dissipation to address different seismic hazards due to its multiphase hysteretic behavior. To improve the design of AF/PUCDs in engineering structures, a highly effective model based on the real deformation of an AF/PUCD is needed to describe its multiphase hysteretic behavior. In this paper, a novel viscoelastic-friction model composed of a viscoelastic component and a friction component is constructed. The hysteretic responses in each phase under various external excitations are described through the different combinations of the viscoelastic component and friction component. The unknown model parameters are identified through the Universal Global Algorithm (UGO). The model results are compared with the experimental results and the results from the Modified Bouc–Wen model and Optimum model. The comparative results show that the viscoelastic-friction model has a higher accuracy in capturing the multiphase hysteresis of AF/PUCD and predicting the boundary of each phase when the AF/PUCD is subjected to various cyclic excitations. Therefore, the viscoelastic-friction model is a good candidate for the design of AF/PUCDs applied in vibration control structures.

Identifying the Influence of Stacking Sequence on Mechanical and Vibration Properties of Bamboo/Glass‐Epoxy Composites

AbstractThe consumption of renewable materials such as natural fiber reinforced composites is highlighted in many engineering applications because of their degradable and environmentally friendly properties. Composite with dedicated natural fibers is limited their use to semi‐structural applications because of their hydrophobic nature and instability under dynamic load. Present research work is attempted to develop woven bamboo (B)/Glass (G) hybrid epoxy composites. The dedicated (BBBB and GGGG) and hybridized composites with different stacking sequences fabricated through the compression molding process and their mechanical and dynamic mechanical properties are investigated. In mechanical properties, the flexural strength and flexural modulus for the GBBG layered composites are best at 210 and 6256 MPa respectively, close to the dedicated glass composite. Impact strength at around 342–368 J m−1 is observed for all hybrids which are extremely good when compared to pure bamboo composite. Experimental modal analysis is also executed to evaluate the dynamic properties as fundamental natural frequencies and the damping ratio. The GBGB composite possesses a fundamental frequency of 25.1 Hz and a damping ratio of 0.0301. The damping of hybrid composites is improved by 96% compared to GGGG stacked composites. The experimental results are well in agreement with the analytical results. These developed bamboo/glass hybrid composites can be a better alternative composite material in semi‐structural applications.

Vibration characteristics of composite damping plate with randomly oriented carbon nanotube reinforced stiffeners

Vibration characteristics of composite damping plate with randomly oriented carbon nanotube reinforced stiffeners

Sound insulation properties of embedded co-cured composite damping sandwich panel under arbitrary boundary conditions

The embedded co-cured composite damping structures (ECCDS) are widely used in engineering fields, it is necessary to build a predictive model of the dynamics of the ECCDS panel. In this paper, a method is promoted for the first time that can predict the acoustic-vibration coupling characteristics of the coupled cavity-ECCDS panel-cavity system. This paper innovatively combines the spectral-geometry method (SGM), penalty-function method (PFM), and the energy-generalised variational principle to develop coupling model of the ECCDS panel with two closed cavities. The displacement of the ECCDS panel and the sound pressure in the cavities are expressed as improved Fourier series. The modal parameters of the cavities and the ECCDS panel are obtained by solving the standard matrix eigenvalue problem, and the accuracy of this method is verified by comparing it with the finite element method (FEM) and experiment. On this basis, the sound transmission loss (STL) can be obtained by the sound pressure method. The factors affecting the sound insulation performance of the ECCDS panel are investigated by parametric analysis. The results show that the addition of a damping layer can improve the sound insulation performance of composite panels. This paper provides a reference for the application of ECCDS panels in engineering.

Numerical and Theoretical Analyses of Friction-Oval Section Mild Steel Rod Composite Dampers

In order to improve the seismic and energy dissipation capacity of the whole structure, a friction-oval section mild steel rod composite damper (FOSRCD) was proposed, and its working principle was clarified. The finite element analysis of FOSRCD was carried out, and the effects of friction, frequency and displacement on the damper performance were studied. Considering the structural characteristics of FOSRCD and the mechanical models of friction dampers and mild steel rod dampers, the restoring force model of the composite dampers was proposed and compared with the numerical simulation results. The results showed that the FOSRCDs had good performance and could provide stable energy dissipation capacities in both directions, with the energy dissipation coefficient exceeding 2.3 and the equivalent damping ratio exceeding 0.37. The theoretical analysis results were in good agreement with the numerical simulation results, which verified the theoretical restoring force model; the FOSRCDs make full use of the friction energy dissipation and the shear and bending energy dissipations of the mild steel rod. It enables the two dampers to work together to achieve the purpose of multi-stage energy dissipation. FOSRCD’s structure allows it to dissipate energy in both the X- and Y-directions. The composite dampers have a variety of restoring force models and can be utilized in a wide range of practical applications.

Mountain Bike Frame Innovation Using Thermplastic Composites - A Case Study

For over 20 years the bike industry has been using composite materials to make mountain bike frames and other components, becoming the default high end material in the past 5-10 years. Thermoset based carbon fiber composites have traditionally led the way, but recently the next generation technology of thermoplastic infused carbon fiber composites have entered the market as recyclability, impact toughness, and vibration damping become more important. In particular, a new class of mountain bike frames has hit the trails as produced by Revved Industries for their in-house brand, Guerrilla Gravity. Increased impact toughness and vibration damping of thermoplastic composites offer attractive performance advantages that are ideal for applications such as mountain bike frames and components. Several thermoplastic composite material options were investigated and PA6/carbon fiber produced by Toray Advanced Composites was selected. A significant breakthrough in thermoplastic composite part forming, co-molding, and fusing has led to a durable and robust design that sets thermoplastic frames apart from their thermoset counterparts. This paper will review the material selection, design and analysis, fabrication, and testing of a mountain bike frame that has proven itself in the market today.

High damping and modulus of aluminum matrix composites reinforced with carbon nanotube skeleton inspired by diamond lattice

Damping and modulus are mutually exclusive properties, and optimizing the overall performance of damping and modulus of materials is of high interest nowadays. In this study, a novel aluminum matrix composite reinforced by a diamond lattice-inspired carbon nanotube skeleton is presented. By means of molecular dynamics simulation, it is demonstrated that the structure can not only increase the internal friction by introducing interface defects, but also ensure the sufficient modulus of the material through the cooperative deformation of sliding and extrusion between the carbon nanotube skeleton and the aluminum matrix. Furthermore, the effect of frequency on energy dissipation is calculated. In contrast to conventional materials possessing a single internal friction peak, this composite structure material has two internal dissipation peaks as a function of frequency. This is due to the fact that viscous and phonon dissipation dominate the energy dissipation in this structural material. The viscous dissipation is caused by the relaxation of disordered atoms in the interface after deviating from the equilibrium state, and the phonon dissipation is created by the coupling of mechanical waves and normal modes of crystalline atoms. The designed composite achieves an unprecedented loss modulus through a trade-off between modulus and damping.

The Reinforcement Effect of Nanoclay on the Damping Characteristics of Hybrid Laminated Composites

The Hybrid Nanocomposite (HNC) laminates are processed by reinforcing the chopped strand mat glass fiber and organically modified montmorillonite clay (OMT) in the polyester matrix. The different percentage by weight (1, 2, 3, and 5% ) of OMT are mixed by high speed shear mixer into the polyester matrix and then the HNC laminates are fabricated by introducing pre-mixed polyester-clay into the CSM by hand lay-up technique. A tensile test result reveals that nanoclay in polyester matrix significantly improves the tensile modulus and strength of HNC. The results also indicate that increasing the amount of nanoclay beyond 2% by weight reduces the mechanical properties but surpassing the basic glass fiber filled system. The reinforcing effect of clay enhances the flexural modulus and strength. Considerable improvement in impact energy absorption is seen from the impact test. Dynamic mechanical analysis shows that incorporation of nanoclay improves the storage modulus and Loss tangent of HNC. Free vibration tests and logarithmic decrement methods are used to predict the dynamic characteristics such as natural frequency, and damping factor for the first four modes of different clay concentrations. Dynamic results show that second phase nanoscale dispersion between the matrix and E-glass fiber significantly enhances the internal damping of hybrid composites.

Mechanical and Viscoelastic Properties of Carbon Fibre Epoxy Composites with Interleaved Graphite Nanoplatelet Layer

The use of interleaving material with viscoelastic properties is one of the most effective solutions to improve the damping capacity of carbon fibre-reinforced polymer (CFRP) laminates. Improving composite damping without threatening mechanical performance is challenging and the use of nanomaterials should lead to the target. In this paper, the effect of a nanostructured interlayer based on graphite nanoplatelets (GNPs) on the damping capacity and fracture toughness of CFRP laminates has been investigated. High-content GNP/epoxy (70 wt/30 wt) coating was sprayed on the surface of CF/epoxy prepregs at two different contents (10 and 40 g/m2) and incorporated at the middle plane of a CFRP laminate. The effect of the GNP areal weights on the viscoelastic and mechanical behaviour of the laminates is investigated. Coupons with low GNP content showed a 25% increase in damping capacity with a trivial reduction in the storage modulus. Moreover, a reduction in interlaminar shear strength (ILSS) and fracture toughness (both mode I and mode II) was observed. The GNP alignment and degree of compaction reached during the process were found to be key parameters on material performances. By increasing the GNP content and compaction, a mitigation on the fracture drop was achieved (−15%).

Free vibration characteristics of composite sandwich plates with embedded viscoelastic layers

Based on the first-order shear deformation theory, the vibration balance equation of composite sandwich plates with embedded viscoelastic layers (CSPEVL) is obtained by using Hamilton principle. The Navier closed-loop solution is used to solve the damping plate structure with four simply supported constraints. The correctness of the derived vibration balance equation is proved by comparing with the simulation results and reference. The verified equations are employed to analyze the dynamic characteristics of the CSPEVL. The results show that as the relative thickness of damping layer decreases, the first four order vibration frequencies of the whole structure all show a declining trend. However, the first four order loss factors are all distributed in an upward convex parabola. In addition, the damping performance of composite damping plate can be significantly enhanced by increasing the width/thickness ratio and aspect ratio of composite plate. More importantly, when the total thickness of the damping layer is constant, the symmetrical distribution of multilayer damping film greatly improves the dynamic performance of the composite structure. The work provides theoretical guidance for the dynamic optimization and structural design of damping sandwich composite structures.