Rubber Layer Thickness Research Articles

Study on vibration attenuation of three-component local resonant pile with low-frequency attenuation zone

The paper explores the increasing concern over environmental vibrations resulting from machine operation and rail transit. Notably, low-frequency vibrations generate surface waves with characteristics like significant energy carrying capacity, long-distance propagation, and slow attenuation. The primary challenge in ground vibration attenuation lies in addressing low-frequency vibrations. The study employs the finite element method to investigate the vibration attenuation of a three-component local resonance pile in three-dimensional space. The analysis delves into the impact of the unit cell structure’s geometry size on bandgaps, and the influences of the period number on the Attenuation Zones (AZs) are also discussed. Furthermore, a comparison is made regarding the vibration attenuation performance of a two-component local resonance pile. The findings reveal that the appropriate design of a three-component local resonance pile can generate low-frequency complete bandgap. The concrete radius, rubber layer thickness, and buried depth of the pile significantly affect Rayleigh wave bandgap. Frequency domain analysis indicates that an increase in period number expands AZs into the bandgap range. Time domain analysis demonstrates a noticeable decrease in ground acceleration amplitude within the bandgap range. The research results presented in this paper offer a novel approach to address the low-frequency vibration attenuation.

Mitigating train-induced building vibrations with rubber bearings designed for horizontal earthquake isolation

As rail transportation, including high-speed railways and urban metros, rapidly expands, its proximity to residential areas decreases, raising concerns about ground-borne vibrations. This study investigates the main characteristics of ground-borne vibrations induced by high-speed railways and metros through substructure method based on 2.5D FEM-MFS (finite element method-the method of fundamental solutions). Besides, the study also delves into the vertical vibration behaviors of buildings caused by train operations, evaluating the effect of laminated rubber bearings designed for horizontal seismic isolation on the train-induced building vibration mitigation. Our findings highlight that the broadband vibrations from train operations might coincide with the natural vibration frequencies of buildings, potentially leading to resonance. Implementing isolators allows the natural frequencies of the vibration modes with larger effective masses to be significantly lower than the dominant frequencies of train-induced ground-borne vibration, reducing the high-frequency responses. Additionally, the vibration mitigation enhances with the increase in the thickness of rubber layer. This research not only aims to reduce vibration levels in buildings adjacent to railways, enhancing the living conditions and health of residents but also underscores the engineering innovations necessary for sustainable urban development.

Exploring key factors affecting the ultimate compression capacity of Unbonded Steel-mesh-reinforced Rubber Bearings

To address bearing-sliding damage in highway bridges during seismic events, the Unbonded Steel-mesh-reinforced Rubber Bearing (USRB) was developed. This novel bearing employs flexible, high-strength steel wire meshes as reinforcement, enhancing lateral deformation capacity and reducing bearing-sliding risk. Recent seismic specifications increased the bearings' vertical design load to 30 MPa, where existing bearings with flexible reinforcements (e.g., fiber-reinforced bearings) fail to meet this standard. Hence, for the first time, our study thoroughly investigated the ultimate compression capacity of USRBs and the key factors influencing the capacity. Through ultimate compression tests on full-scale prototypes, we demonstrated that USRBs can comply with heightened seismic requirements, with primary failure attributed to the tensile failure of the steel mesh reinforcement. These tests were complemented by 3D finite element modeling in ANSYS, employing the LINK180 elements for mesh reinforcement and defining the ultimate capacity as the point at which reinforcement stress reached tensile strength. This particular modeling approach, validated against experimental data, can accurately predict the ultimate compression capacity and the force-deformation response of USRBs. A comprehensive parametric analysis, using the validated modeling approach and an advanced statistical method LHS-PRCC, was conducted to identify the key factors influencing the compressive capacity, including bearing geometric parameters (i.e., bearing width, the second shape factor, and rubber layer thickness), steel-mesh configuration characteristics, and steel-mesh material properties. Our findings emphasize the significance of rubber layer thickness, steel mesh weight, and steel wire tensile strength and strain in influencing the USRBs' ultimate compression capacity. Based on these key factors, an empirical equation for the ultimate compression capacity of USRBs was established to guide the optimization design of USRBs. This study not only fills the gap in USRB's performance under extensive compression but also provides a foundation for future optimization of these bearings to enhance their performance in bridge engineering.

Characterization and prediction of micro channel depth of ultra-thin bipolar plates for PEMFCs

In this study, a combination of experimental and statistical methods were employed to precisely determine the micro channel depth in ultra-thin metallic bipolar plates fabricated from 316 stainless steel with a thickness of 0.1 mm. The investigation centers on the rubber pad forming process and its role in the production of these critical components for Proton Exchange Membrane Fuel Cells (PEMFCs). To advance the understanding of this manufacturing process, experimental tests were designed using a Design of Experiment (DOE) technique and subsequently developed a predictive model using Response Surface Methodology (RSM). The research reveals a direct, quantifiable relationship between the channel depth in metallic bipolar plates and the magnitude of the applied force. Also, the pivotal role of rubber thickness as a dominant factor influencing channel depth was explored. Furthermore, it is revealed that augmenting the channel depth in these plates is attainable through a reduction in rubber hardness and an increase in rubber thickness. However, the benefits diminish once the rubber layer thickness exceeds a specific threshold. Moreover, the results underscore that the primary influential factors in this process include force, hardness, thickness, as well as the interplay between force and rubber thickness. The proposed model's accuracy is reaffirmed through an average error rate of approximately 5.39%, signifying its reliability in predicting microchannel depth. This research contributes novel insights into the manufacturing of ultra-thin metallic bipolar plates for PEMFCs, shedding light on the critical parameters influencing channel depth and their interrelationships. The significance and engineering value of this work lies in its potential for enhancing the design and manufacturing of metallic bipolar plates for PEMFCs. Precise control of microchannel dimensions is crucial for enhancing PEMFC performance and efficiency. This research not only advances clean energy technology but also contributes to the broader goal of achieving sustainable energy solutions, making it a noteworthy and timely contribution to the field.

Explosion Behaviors of Scaled Shallow-Buried Concrete–Rubber-Laminated Annular Metastructures: Evaluation of Shock Wave Attenuation

The attenuation of impact inducer vibration is critical to the safety of underground protection structure, equipment and personnel. Metamaterials and metastructures show great potential in terms of sound and impact attenuation. To effectively attenuate ground shock-induced vibration of underground protective structures, scaled shallow-buried annular metastructures with concrete–rubber layered structures were proposed and constructed. Underground explosion experiments were performed to investigate the vibration attenuation effect of annular metastructures with different layered structures. It is clear in this research only annular metastructures with concrete–rubber–concrete structures like annular metastructure model B6 have the most excellent wave attenuation performances, whose rubber layer thickness must be over 6[Formula: see text]mm and hardness is 20[Formula: see text]HA. Other layered structures with rubber layer thickness of 0.3[Formula: see text]cm or with more layers cannot effectively attenuate the shock wave in this research.

Geometric parameters optimization on storage performance degradation of ultrasonic motor based on simulation analysis

The performance of ultrasonic motor will drift due to material degradation and other reasons during long-term storage, which will directly affect the working performance after storage. Aiming at the optimization design of geometric parameters for performance storage degradation, this paper takes the piezoelectric constant d31 of ceramic chip and the elastic modulus of colloid as the characterization parameters of product storage degradation, and takes the stator tooth spacing and the thickness of rubber layer as the analysis objects of product geometric parameters optimization, and proposes a simulation analysis method based on finite element model. Through the analysis of the simulation results, it is found that the increase of the stator tooth spacing will lead to the increase of the change rate of the 5-wave modal frequency with the degradation of the material properties, and the decrease of the overall change rate of the amplitude. However, properly reducing the thickness of the adhesive layer can effectively reduce the influence of the degradation of the piezoelectric properties of the ceramic chip and the hardening of the gel on the frequency response characteristics of the stator of the ultrasonic motor under long-term storage.

Close-in explosion behaviors of scaled concrete–rubber layered circular meta-tunnels

Attenuating shock-induced vibration is crucial for the safety of underground protective structures, equipment, and personnel. Metamaterials and metastructures demonstrate great potential for sound and shock attenuation. However, to further enhance protection against blast shock waves, more rational metamaterials and metastructures need to be proposed and designed. Additionally, more experimental and theoretical studies are required to explore the vibration attenuation mechanisms and effects of these metastructures. To this end, this study proposes layered meta-structures consisting of stiff concrete layers and thin, soft rubber layers. Scaled meta-tunnel models were constructed, and close-in explosion experiments were carried out to investigate their vibration mitigation performance. The impacts of critical parameters, including layer materials, layer thickness, and scaled distance, on the vibration attenuation effects were investigated through comparing displacements, strains, acceleration data, and failure characteristics. The results reveal that under close-in field explosions with small TNT mass all these scaled models have greater displacement and more cracks, for laminated structure weakens the integral rigidity of the metastructure. Under great TNT mass, the difference gets much smaller. But all these structures have excellent vibration attenuation. The acceleration attenuation rate exceeds 98% for two-concrete-layered models with rubber layer thickness of 0.6 cm under explosion with TNT mass of 0.1 kg and stand-off distance of 1.0 m. When the TNT mass increases, the acceleration attenuation ability will be weakened. In this research, more layers will improve vibration attenuation only under high equivalent explosions as fracture of each layer will dissipate more energy. Overall, this study sheds light on the efficacy of meta-structures in attenuating vibration induced by explosive blasts and lays the groundwork for more sophisticated and advanced protective engineering designs.

Locally resonant porous phononic crystal sensor for heavy metals detection: A new approach of highly sensitive liquid sensors

In this research, a novel and highly sensitive phononic crystal (PnC) sensor is presented for the detection of CdBr2 concentrations at a low scale (ppm) which is considered a highly toxic heavy metal ion in freshwater. The proposed sensor is composed of two thin layers of rubber covering both the top and bottom surfaces of a one-dimensional ternary porous silicon (PSi) PnC. As a result, the whole designed structure is arranged as {rubber/[PSi1/PSi2/PSi3]N/rubber}. The appearance of local resonant modes is due to the presence of two thin rubber layers as a cap layer of the PnC design. In particular, the spectral position of the modes is significantly tuned when filling the PSi layers with CdBr2 ions. It is worth mentioning that the novelty of this work is mainly focused on three axes. The first one is the use of locally resonant PnCs (not conventional defective ones) as highly sensitive biosensors. The second one, the liquid of interest here is considered a dangerous aqueous solution with a very low scale (ppm). The last promising point, we proposed the pores inside Si layers are filled with a liquid material in contrast to most of the micromechanics methods of composite materials that supposed the pores are empty (just voids are inside). To realize the best performance of this sensor, an optimization strategy of some related parameters such as the rubber layer thickness, the geometry of the PnC, and the unit cell number was conducted. In this regard, the proposed sensor provides promising values of sensitivity, quality factor, detection limit, and damping rate of 47.25 Hz/ppm, 2756.2, 82 ppm, and 0.00018, respectively. Therefore, the present design could be of serious contribution to liquid sensors and bio-sensing applications due to its simplicity, novelty, and high performance.

Experimental and numerical analysis of low-velocity impact damage of CFRP laminates with rubber protective layer

Carbon fiber reinforced polymers (CFRP) are widely used nowadays as primary and secondary bearing structures in the aviation industry. However, CFRP structures are threatened by unpredictable low-velocity impact events (caused by dropped tools, etc.) during the assembly process, which can cause impact damages. To prevent CFRP damage during the assembly process, a rubber layer can be placed on the surface of the CFRP to form a protective hybrid structure. The influence of rubber layer thickness on the protection effect and on the impact response of the hybrid structure were first investigated in this study. The experimental results indicate that the rubber layer significantly improved the CFRP’s impact resistance, with fewer damage modes and less damage area observed. Furthermore, the thicker the rubber layer places, the lower the CFRP delamination position occurs. The whole impact process of this hybrid structure was simulated using the mixed-mode damage criterion for CFRP laminate and the hyperelastic law for the rubber layer. The finite element model was refined with mesh size and contact behavior corresponding to the experiment condition, which showed good agreements with impact response and delamination area experiments. Some internal damage details and damage evolution were also discussed using the finite element model.

An experimental study on mechanical behavior of nylon fabric laminated rubber bearings

Five samples of the nylon fabric laminated rubber bearing were manufactured with different rubber layer thickness and nylon cloth specifications. The compression and compression shear tests were conducted to evaluate the mechanical properties of the bearings. Results show the novel bearings’ vertical stiffness is significantly lower than that of laminated steel rubber bearings, but their vertical damping ratio can reach 7%. The effective horizontal stiffness decreases with increasing shear strain due to rollover deformation. The bearings do not get seriously damaged when the shear strain is 300%. The equivalent damping ratio of the bearings varies in the range of 9%–13%.

Nondestructive Assessment of Elastomeric Bridge Bearings Using 3D Digital Image Correlation

Elastomeric bridge bearings are installed between the bridge superstructure and substructure to accommodate translational and rotational deformations. The manufacturing quality of elastomeric bridge bearings is of high significance because manufacturing defects (such as variations in rubber layer thickness and nonparallel steel laminates) may jeopardize their short- and long-term structural behavior and integrity. Current quality control procedures involve destructive testing of samples of bearings from a lot. This type of testing is time consuming and costly, and thus limited to a relatively small sample size, which may undermine confidence in the quality of remaining bearings in the lot. This paper presents an alternative, vision-based assessment methodology for the nondestructive identification of the internal structure of elastomeric bridge bearings. The methodology capitalizes on the high deformability of rubber and the near inextensibility of the steel laminates, which together result in a unique deformation pattern on the vertical surfaces of a bearing when it is subjected to axial load. This deformation pattern features local extrema in in-plane strain and horizontal displacement fields on the vertical surfaces. These local extrema are analyzed to deduce the thicknesses of the rubber layers and rubber side covers. The methodology is developed based on three-dimensional finite-element analyses (3D-FEA). Then, three-dimensional digital image correlation (3D-DIC) is used in experimental tests to evaluate its capability to identify manufacturing defects in elastomeric bridge bearings. Finally, the methodology is validated against destructive tests. The nondestructive method presented in this study is conducted in conjunction with compressive tests that departments of transportation carry out routinely and is therefore expected to facilitate rapid and cost-effective qualification of elastomeric bridge bearings.

Probability Distribution Characteristics and Statistical Parameters of the Horizontal Stiffness of Rubber Isolation Bearings

ABSTRACT The manufacturing of rubber bearing is complicated, the horizontal stiffness of the final product maybe greatly affected by the uncertainties during the processing, thus, it is necessary to study the distribution characteristics of the rubber bearings’ horizontal stiffness, and its influence on the seismic performance of the isolation structure. The rubber layer thickness was taken as a comprehensive index, measurements were carried out before and after vulcanization, the relationship between the rubber layer thickness and the variation of bearing’s horizontal stiffness was deduced, and an optimization method to reduce the variation of bearing stiffness was proposed. Then, based on the equivalent shear stiffness samples of 224 rubber bearings of 3 different specifications produced by two manufacturers, systematic statistical analysis and probability distribution tests were carried out. Result shown that the equivalent shear stiffness obeys the I-type minimum-value distribution. Finally, the influence of the variation of the bearing’s stiffness on the seismic performance of the rubber bearing isolation structure was studied. The results shown that the probability distribution form of the rubber bearings stiffness has a certain influence on the adjustment coefficient of the isolation structure, but the damping effect of the isolation structure still has sufficient safety reserve according to China’s Code for Seismic Design of Buildings.

Response Performance Characteristics of LRB Base Isolator for Cyclotron Building Due to Parts Sizing

Study of the effects of part sizing on Lead Rubber Bearing Base (LRB) isolator for cyclotron building foundation application has been carried out. The cyclotron building design must be able to withstand earthquake loads without damaging either the structural integrity or the functionality of the building as the shielding against the radiation rays generated when the cyclotron operates. Lead Rubber Bearing (LRB) base isolators are designed for the cyclotron building foundation to provide structural integrity and reliability against earthquakes. The LRB base isolator constructed as a stack of flat rubber and steel ring plates with lead in the center. Variation of the sizes of the LRB parts are bringing up the necessity to investigate further the response characteristics of the cyclotron building due to an earthquake excitation. Parts sizing of the LRB are of the steel plates thickness, the rubber layer thickness as well as the diameter of the leads. From the simulation then it is revealed that every configuration size is giving different effective stiffness, vertical stiffness as well as damping values in vibration isolation percentage value. Results from an LRB static analysis then are included as well in the dynamic analysis to determine differences in cyclotron building responses. The computer FEA simulation running on Abaqus and Solid Work® 3D FEM software platform revealed that changes in the thickness of the plate, rubber layer and lead diameter affected the dynamic responses of the cyclotron buildings when subjected to earthquake loads.

Numerical and experimental investigation of impact on bilayer aluminum-rubber composite plate

Abstract This paper aims to investigate the performance of an aluminum–rubber composite plate under impact loading. The impact resistance of the plate has been evaluated using both experimental and numerical methods. The experimental tests were carried out using gas gun at velocities of 75, 101, 144 and 168 m/s. The energy absorption of composite plates has been closely examined for all samples. The effect of rubber layer positioning either on front face or on back face of the aluminum plate was also evaluated. It was found that the composite plate with rubber on front face provides higher performance to absorb the energy. In parallel to the experiment, a finite element model was created using the finite element software LS-DYNA to simulate the response of the aluminum–rubber composite plate under a high energy rate loading condition. The data obtained from finite element modeling shown a close agreement with the experimental results in terms of failure mechanism and energy absorption. In addition, a parametric study was carried out incorporating different impact velocities, rubber formulation, rubber layer thickness, interface bonding strength between rubber and aluminum layers and ballistic performance of aluminum-rubber sandwich panel. It was concluded that by increasing the rubber layer's thickness the energy absorption of the composite plate will be increased, especially when rubber layer placed in front face of the aluminum plate. Although at high interface bonding of rubber and aluminum layer, the composite with rubber layer in front face has better performance, but low bonding of interface lead to higher energy absorption in back face configuration.

Numerical Simulation of the Stress-Strain State of Thin-Layer Rubber-Metal Vibration Absorber Elements Under Nonlinear Deformation

Stress-strain state components of thin-layer rubber-metal elements are investigated. The compression level of a thin rubber layer under the action of vertically applied stress is calculated. For simplified hypotheses the relationship between the rubber layer thickness reduction and its radius-thickness ratio was analytically derived. The problem was solved under linear-elastic deformation of a rubber layer vulcanized onto the metal plates. For numerical calculations, weak rubber compressibility was simulated with the moment finite element scheme for weakly compressible materials, involving the triple approximation of displacement fields, strain components, and a volume variation function. The numerical solution was obtained by the finite element method for different layer radii and thicknesses under geometrically nonlinear elastic and viscoelastic deformation of the rubber material. The geometrical nonlinearity is described by the nonlinear strain tensor. Viscoelastic rubber properties are simulated by the hereditary Boltzmann– Volterra theory with the Rabotnov relaxation kernel. Nonlinear boundary problems are solved by the modified Newton–Kantorovich method. The calculation is effected for the two cases of curing the rubber layer onto the metal elements of the structure. The first case assumes that the rubber layer is vulcanized onto the metal plates, in the second one, it can freely slide over their surface. For the first case, numerical results are compared with the analytical solution. The effect of geometrical nonlinearity and viscoelastic rubber properties on the rubber layer thickness reduction was examined.

Assessment of the Performance of Sediments and Scrap Rubber Layers to Filter the Leachate of Landfills

The leachate from landfills is considered as a great danger to the environment and human health. This danger is represented in its toxic components. The major purpose of this project is how to get rid of the toxic materials by a collection of sediments, scrap rubber and geotextile layers. Ten (10) cells with different compositions were used in this process, and the physicochemical analysis were made on water resulted from filtration. And permeability test on all cells. The results show that the physicochemical factors reduce with the increase of thickness of sediment layer. The physicochemical factors of water resulted from the cells which contain scrap rubber with dimensions of 0.2mm are fewer than the ones with dimensions of 4mm. The permeability factor rise in all the cells with the increase of scrap rubber layer thickness of both types.Cell 5 with no scrap rubber gave better results in physicochemical factors but weak results in permeability factor. Cell 4 gave good results in both physicochemical and permeability factors

Critical rubber layer thickness of core-shell particles with a rigid core and a soft shell for toughening of epoxy resins without loss of elastic modulus and strength

Core-shell particles with a rigid silica core and a poly(butyl acrylate) (PBA) rubber shell are used to toughen epoxy resins without loss of elastic modulus and tensile strength. Both the diameter of silica core (D) and thickness of PBA shell (Ts) of silica-PBA core-shell particles are accurately controlled by sol-gel synthesis and seed emulsion polymerization process, respectively. From the results of notched Izod impact tests, a brittle-ductile transition of these epoxy/silica-PBA composites occurs when the rubber shell thickness (Ts) exceeds a critical value (Tsbd). It is found that Tsbd increases with increasing D which implies a critical rubber content (10 wt%) in the core-shell particles or a critical Ts/D ratio (0.0375), above which all composites transit from brittle to ductile failure. The composite elastic modulus decreases with increasing Ts. However, the critical thickness values of Tsm and Tss, below which composite modulus and tensile strength, respectively, are equal to or higher than the corresponding epoxy matrix values, are both larger than Tsbd. These results prove that brittle polymers can be toughened without loss of elastic modulus and tensile strength. However, the critical surface-to-surface inter-particle distance (Lc) is controlled by both properties of the core-shell particles and polymer matrix. When the rubber shell thickness Ts > Tsbd, Lc is increased when D is decreased. But when Ts < Tsbd, the brittle-to-ductile transition cannot occur, even when Lc is less than 100 nm.

Experiment of Ultimate Shear Failure and Friction Sliding Performance of Rubber Bearings of Bridges

Introduction: To fully ascertain the ultimate shear failure state and friction sliding performance of laminated rubber bearings used in bridges, a series of cyclic loading tests on such laminated rubber bearings was conducted. Method: The energy dissipation characteristics of rubber bearings with two fixed end plates, rubber bearings with unilateral friction sliding and a lead rubber bearing (LRB) under a low-frequency cyclic load were compared and analyzed. Results and conclusion: The results showed that (1) the ultimate shear deformation of the rubber bearings with two fixed end plates reached 300% to 400% of the rubber layer thickness. The damage was mainly focused on the rubber layer fracture. The energy dissipation capacity of the bearings was weak, and the hysteresis curve presented a narrow zonal shape. (2) The rubber bearings with unilateral friction sliding had a similar energy dissipation capacity compared to the LRB. The maximum energy dissipation in a single cycle could reach 126% of the LRB’s maximum energy dissipation. With an increase in the sliding distance, the dissipated energy continuously increased. The shear deformation of the bearing no longer increased after reaching its maximum. After the test, the bearings remained in good condition. The hysteresis curves of load-displacement presented a bilinear shape. (3) Under cyclic loading, the energy dissipation capacity of LRBs was stable. The LRBs played an effective role in energy dissipation during loading. After the test, the LRBs nearly returned to their original condition. The hysteresis curves of LRB were always fuller than the laminated rubber bearings.

Experimental Study on Friction Sliding Performance of Rubber Bearings in Bridges

To fully ascertain the ultimate shear failure state and the friction sliding performance of laminated rubber bearings in bridges, a series of cyclic loading tests were conducted. The energy dissipation characteristics of the laminated rubber bearings with two end plates, rubber bearings with unilateral friction sliding, and lead rubber bearing (LRB) under low-frequency cyclic loads were compared and analyzed. The results showed the following. (1) The ultimate shear deformation of the rubber bearings with two end plates could reach 300% to 400% of the rubber layer thickness. The energy dissipation capacity of the bearings was weak, and the hysteresis curves presented narrow zonal shapes. (2) The rubber bearings with unilateral friction sliding had similar energy dissipation capacities compared to the LRB. With the increase of the sliding distance, the dissipated energy continuously enlarged. The shear deformation of the bearing was no longer increased after reaching the maximum. After the test, the bearings remained in a good condition. The hysteresis curves of the load and displacement presented bilinear shapes. (3) Under the cyclic loading, the energy dissipation capacity of LRB was stable. The hysteresis curves of LRB were always fuller than the laminated rubber bearings.

In-situ dimensional measurement system for overlapped rubber layers

For the semi-manufactured rubber layers in tire manufacturing industry, the rubber layers need to be joined by the agglutinate conjunction. The width of the conjunction and the rubber thickness must be acquired to ensure the quality of the semi-manufactured rubber. In this investigation, a self-developed dimensional measurement system for agglutinate conjunction is proposed which can be utilized for in situ dimensional measurement during a high-speed manufacturing process. The measured dimensions include both the conjunction width and rubber layer thickness. The standard deviations of the deviations of conjunction widths and the rubber layer thicknesses are about 0.43 and 0.029 mm.