Rubber Joint Research Articles

Improving stability and curving passing performance for railway vehicles with a variable stiffness MRF rubber joint

With the growing need for effective intercity transport, the need for more advanced rail vehicle technology has never been greater. The conflicting primary longitudinal suspension requirements of high speed stability and curving performance limit the development of rail vehicle technology. This paper presents a novel magnetorheological fluid based joint with variable stiffness characteristics for the purpose of overcoming this parameter conflict. Firstly, the joint design and working principle is developed. Following this, a prototype is tested by MTS to characterize its variable stiffness properties under a range of conditions. Lastly, the performance of the proposed MRF rubber joint with regard to improving train stability and curving performance is numerically evaluated.

Effects of Hybrid Structures on the Stress Reduction and Thermal Properties of Joints in Electronics Devices

Electronics devices consist of silicon chips, copper leads, resin or ceramics substrates and which are jointed to each other with solder, conductive adhesive or other materials. Each coefficient of thermal expansion is different and it causes strain concentration and cracks. The solder easily deformed by the difference of the thermal expansion and it relieved the stress on the devices however the epoxy resin of the conductive adhesives are harder. So we suggested the composed joint including the relaxation layers of low elastic material. The shear strength and elongation of the epoxy resin joint, silicone rubber joint and the composite joint of the two materials were investigated. The analytical study was carried out to clarify the stress reduction effect of the design of the relaxation layer in the composite joints. The parameters such as the width, height, pitch and the distance of the relaxation layer from the joint edge are investigated. The high relaxation layer close to the joint edge effectively reduced the stress of the joint. The stress reduction effect appeared in the different pitch of the layers.

ANSYS Simulation of Loads Experienced by the Peduncle of a Design of Robotic Fish

Aims: This article aims at simulating the forces and dynamic load that the peduncle of a robotic fish using vulcanized natural rubber for its joint and plywood for its tail fin will experience. Methodology: Using standard strength of material equations and constitutive equation that fits the selected natural rubber, the loads that will be encountered in a water with density 990kg/m were calculated. The result was then used in ANSYS multiphysics environment to setup the simulation of the response of the peduncle to the calculated loads. Autodesk Inventor 7 was used for the geometrical drawings and calculations such as area and centroid of the non standard shape. Furthermore, the Payne effect for the rubber joint was found experimentally as its result will guide in the threshold of tail oscillation frequency allowed. Results: von Mises stress within the components of the peduncle due to the drag load was found to be 0.03kN/m to 4.64kN/m for the rubber and 0.03kN/m to 41.48kN/m for the plywood fin. Stress experienced by the peduncle under its own weight shows that for the rubber component, the maximum von Mises stress experienced by the rubber is 4.9kN/m and for the plywood material, it is 1.087kN/m. Test for warping/ bending of the peduncle shows a straight isoline pattern. Tensile stress within the epoxy bonded joints shows a uniform bond pattern. The dynamic torque experienced by the peduncle increases with frequency of oscillation and even more rapidly as the angle of swing increases though at a fixed ratio to each other. Frequency induced softening (Payne effect) shows that the rubber will become soft as the frequency reaches 25Hz. Research Article British Journal of Applied Science & Technology, 3(4): 1430-1446, 2013 1431 Conclusion: The use of plywood material for the fin and vulcanized natural rubber for the joint and using epoxy glue for the designed peduncle of the robotic fish will be capable of withstanding the stresses that will be developed in real life scenario.

Rubber Joint for Fatigue Crack Factors Numerical Analysis of Certain Vehicle

The main factor of rubber fatigue was stress field. But the way is not sensitive in many cases. To clarify which factors were the main for predict the locations of fatigue crack, we analyzed the factors of stress field and strain field of rubber joint, and relations between the factors and the locations of fatigue crack, using 3D FE simulation. The result showed stress concentration was not sensitive to predict the locations of fatigue crack. The locations are close to strain concentration of rubber joint. In this paper we propose the approach of using strain concentration to predict the fatigue crack locations for rubber joint. This result is significant for the rubber joint design and the study of fatigue strength theoretic.

ARMAMENT AND MILITARY EQUIPMENT POLYMER COMPOSITE AGEING

In the process of planning military operations, it is necessary to know technical and combat readiness of vehicles. Knowledge of the pass mode potential of individual vehicles is very important while organizing transport operations. So far, in a situation where the elements determining the suitability of a vehicle were made of metal, such potential has been estimated on the basis of the difference between the service life of a vehicle and meter readings. The following study demonstrates the inappropriateness of such an approach in relation to elements made of polymers. A simplified way of assessing loss of the pass mode potential (based on measurements of the labor symptoms) has been presented based on an example of a rubber and metal joint of a caterpillar. It was found that during 8 years the storage of these elements, their utility potential loss is up to 40% of the initial potential.

A three-level non-deterministic modeling methodology for the NVH behavior of rubber connections

Abstract Complex built-up structures such as vehicles have a variety of joint types, such as spot-welds, bolted joints, rubber joints, etc. Rubber joints highly contribute to the nonlinear level of the structure and are a major source of uncertainties and variability. In the general framework of developing engineering tools for virtual prototyping and product refinement, the modeling of the NVH behavior of rubber joints involve the computational burden of including a detailed nonlinear model of the joint and the uncertainties and variability typical of that joint in a full-scale system model. However, in an engineering design phase the knowledge on the joint rubber material properties is typically poor, and the working conditions a rubber joint will experience are generally not known in detail. This lack of knowledge often do not justify the computational burden and the modeling effort of including detailed nonlinear models of the joint in a full-scale system model. Driven by these issues a non-deterministic numerical methodology based on a three-level modeling approach is being developed. The methodology aims at evaluating directly in the frequency domain the sensitivity of the NVH behavior of a full-scale system model to the rubber joint material properties when nonlinear visco-elastic rubber material behavior is considered. Rather than including directly in the model a representation of the rubber nonlinear visco-elastic behavior, the methodology proposes to model the material nonlinear visco-elastic behavior by using a linear visco-elastic material model defined in an interval sense, from which the scatter on the full-scale system NVH response is evaluated. Furthermore the development of a multi-level solution scheme allows to reduce the computational burden introduced by the non-deterministic approach by allowing the definition of an equivalent linear interval parametric rubber joint model, ready to be assembled in a full-scale system model at a reasonable computational cost. By using a commercial finite element code the developed methodology is illustrated through a numerical case-study: the low-frequency dynamic analysis of automotive door weather-strip seals.

Wheel running fatigue testing of RC slab with rubber joint

Wheel running fatigue testing of RC slab with rubber joint

A new water-based chemical treatment based on sodium dichloroisocyanurate (DCI) for rubber soles in the footwear industry

A new water-based chemical treatment based on sodium dichloroisocyanurate (DCI) solutions for rubber soles of different natures is reported in this study. Different concentrations (1-5 wt%) of DCI and two rubber formulations (vulcanized styrene-butadiene rubber, R2; thermoplastic rubber, TR) were considered. The effects produced by treatment of the rubber soles with DCI were compared with the standard halogenation method using trichloroisocyanuric acid (TCI) solutions in an organic solvent (ethyl acetate). The effects of chlorination on the rubber surfaces were studied using contact angle measurements, ATR-IR spectroscopy, and scanning electron microscopy. The adhesion strength was obtained from T-peel strength tests on canvas/PUD adhesive/treated rubber joints. The adhesive used throughout this study was a water-based polyurethane dispersion (PUD). The surface treatment with aqueous DCI solutions modified the surface chemistry of both the TR and R2 rubbers, creating C—Cl moieties on the surface and removing the zinc stearate from the R2 rubber surface. The use of a low DCI concentration in water was less effective in modifying the TR rubber, but was sufficient to obtain good T-peel strength values for the R2 rubber joints. On the other hand, heterogeneities and cracks were created on the rubber surface (mainly on the R2 rubber surface), which may contribute to an increase in the mechanical interlocking with the adhesive. A noticeable increase in the T-peel strength and a cohesive failure in the rubber for the joints produced with TR rubber were obtained when the rubber was treated with aqueous DCI solutions. For the canvas/PUD adhesive/chlorinated R2 rubber joint, the failure was located in a thin surface layer on the canvas. Finally, the surface treatment with TCI in ethyl acetate produced a more significant surface modification on both the TR and the R2 rubber, creating deeper roughness on the R2 rubber surface. Consequently, higher peel strength values were obtained using TCI solutions in ethyl acetate. Furthermore, the T-peel strength values were high in all joints produced with TR rubber treated with either TCI solution in ethyl acetate or aqueous DCI solution.

Elastomeric joint performance of PVC, VC, and FRC Pipes

For rubber ring joints to resist plant root penetration in drier countries, it has been reported and promulgated into some national standards that a sufficiently high contact pressure between the rubber and the pipe must be maintained. The evaluation of the appropriate interfacial pressure to be used has been under discussion for some time and different values have been stated in different standards. This matter has been the subject of considerable controversy, and decisions on the interface pressure used will affect the performance and ease of insertion of a rubber ring joint. This paper reports and discusses previous and current research on root penetration past elastomeric joints, the existing test requirements of elastomeric pipe joints for resisting root penetration given in standards, and the inconsistencies in performance requirements across the different pipe material types. The initial interface sealing pressures for commonly used PVC. VC and FRC joints were assessed and these are discussed in light of the accelerated root intrusion tests performed in Black Hill Flora Centre in Adelaide, South Australia.

Photoelastic Studies on Rubber-to-Rubber Joints

Abstract Photoelasticity is a method which yields information on the principal stress difference and orientation in a composite structure. Various problems associated with this technique, especially those concerning the fundamental relationship between the fringe order and the stress, have yet to be investigated. A few studies of this relationship in a universal stress state have been presented, particularly in the field of rubber-to-metal and rubber-to-fabric composites, but no evaluations have so far been made in the field of rubber-to-rubber joints. Applying the photoelastic method, we report our observations on the stress distribution in a natural rubber to natural rubber joint subjected to uniaxial tension. A comparison between the results of experimental photoelastic studies and the corresponding computer modelling has been illustrated. The theoretical displacement pattern of the angular joints of bi-rubber part has also been highlighted.

Multi-stage mixer-settler planet centrifuge : Preliminary studies on partition of macromolecules with organic-aqueous and aqueous-aqueous two-phase solvent systems

A rotary-seal-free planetary centrifuge holds a separation column which consists of multiple partition units ( ca. 200) connected in series with transfer tubes. In the cavity of each partition unit the transfer tube extends to form a mixer which vibrates to stir the contents under an oscillating force field generated by the planetary motion of the centrifuge. Consequently, solutes locally introduced at the inlet of the column are subjected to an efficient partition process in each partition unit and separated according to their partition coefficients. The mixer tube equipped with a flexible silicone rubber joint was found to produce excellent results for partition with viscous polymer phase systems. The capability of the method was demonstrated on separation of cytochrome c and lysozyme using a PEG-aqueous dibasic potassium phosphate-aqueous two-phase solvent system.

Production of Brick Veneer Precast Concrete Panels

T he continued interest in brick veneer panels has resulted in many different methods of brick positioning to ensure proper location and secure fit during production. All of these methods involve a grid system, the most popular consisting of either a rubber form liner or a wooden base tray with shaped wood joint sections. In some cases, this grid system has successfully incorporated rubber joint sections and it is conceivable that other systems using urethane, plaster or sand may be common, However, these latter grid systems are not within the experience of the author. The appearance of brick veneer panels is principally achieved by the selected brick with type, size and texture contributing to overall color. Also, the clarity with which the brick is featured will depend upon the profile of the joint between bricks, thus requiring a choice between recessed, flush or concave-tooled joints. The final element in the appearance of the panel is the mortar or concrete used in the joints. The blending of the above factors into unit sections and proportions suitable for a given structure is within the scope of the architect. Panel sections shown in this article will illustrate the freedom of expression available through precasting techniques, which could not economically be accommodated in field applications. Freedom of aesthetic expression is only one advantage precasting affords over site laid-up masonry, Other advantages include less efflorescence since precasting techniques do not require chloride accelerators in the mortar; absence of unsightly galvanized shelf angles to support site laid-up masonry; absence of the scaffolding network; and lower unit costs afforded by precasting techniques. Any disadvantages in using brick veneer precast units lie with the precast manufacturer. The inflexibility of the joint-forming method in plant work does not compare to the simplicity of site laid-up brick which may be readily seated and moved in a bed of mortar. The precast manufacturer is also casting

A chamber preserving cellular function of the isolated rabbit retina suited for extracellular and intracellular recordings.

The isolated retina of rabbit lies on nylon tissue fixed in a ring, which is placed in a chamber. The lower side of the retina, by choice the receptor or ganglion cell side, is superfused by a plasma saline mixture kept at 35 degrees C. At the upper side of the retina, warm humidified oxygen is added. The two sides are isolated from each other by a rubber joint. ERGs with b waves of about 1 mV indicate a good function of retinal cells. The receptor potential is recorded extracellularly between an intraretinal microelectrode and a reference electrode at the receptor side (amplitude typically about 300 microV). The few intracellular records were hyperpolarizations to white and red light with an initial overshoot and a plateau.

Fatigue life determinations of rubber springs

A method for the determination of fatigue lives of rubber springs is described which is based on a fracture mechanics approach. Fatigue experiments have been performed on model components consisting of solid rubber cylinders bonded between metal endpieces of the same diameter. Crack growth in uniaxial compression followed an approximately parabolic locus. Tearing energies were determined both experimentally and theoretically. The results could be plotted on a unique curve of tearing energy, T. versus crack growth rate, dc/dN, as could results from tests on thin strips of rubber fatigued in simple extension. Application of the approach is described to two case histories. The first is the design of a large spherical rubber joint to support an offshore oil-production platform, and the second is the fatigue analysis of a rubber antivibration mounting for a rail car after 2·5 years service.

Durability of Silicone Implants —An In Vivo Study

SUMMARY The durability of silicone rubber joint implants has been analyzed in the light of the chemical and physical properties of Silastic 372, the design of the finger joint distributing load flexible hinge, and a long term in vivo lipid absorption study of retrieved implants. In a series of 95 finger joint implants and 28 implants retrieved from other joints, it was clearly demonstrated that there is no correlation between lipid levels in the implants and either the incidence of breakage or the duration of implantation. It was shown that most fractures have occurred in a small group of severely ill rheumatoid patients and were related to surgical pitfalls or exacerbation of the disease process. We have demonstrated that the present implant has proved to be durable in the majority of cases. We have concluded that fracture of these implants has no relation to lipid absorption levels and that they are the result of tear propagation occurring following lacerations of the implant surface. Newer technological advances in silicone chemistry will further refine and insure the durability of these flexible joint implants.

In vivo testing of silicone rubber joint implants for lipid absorption.

AbstractSilicone rubber implants removed from patients undergoing revision arthroplasty were examined for breakage and cracks and analyzed for lipid content. No relationship was observed between lipids extracted from the implants and the implantation time. Neither was the absorption of lipids and the incidence of breakage of the implants found to be related. Various factors contributing to the possible failure and breakage of the joint implants are discussed.

Rubber Gaskets for Pipe

This article discusses the development of several types of flexible joints for all sizes of concrete pressure and sewer pipe. The behavior of rubber gasket joints and the material properties required for successful performance are described. Except for the 44‐durometer gaskets tested for contact pressure and compression set of stretched specimens, all results and conclusions are based upon the rubber and steel joint in which the fully confined 60‐durometer gasket fills the gasket groove.

The Dictating Machine in the Schools

The dictating machine' is the most improved type of phonograph used for recording and reproducing the spoken word. Its principal use is to enable the business man to dictate to the machine at any time or place or speed, and have it typewritten at a later time without the use of stenography. Its use in business offices has forced our schools to instal the machine in order to give proper training to the pupils of the commercial department. It also removes a great burden from the typewriting teacher, since one dictation can be used by a number of pupils at different times, and at varying speed. By use of a multiple hearing device, ten, or sometimes thirty, pupils can take the same dictation at the same time, and reproduce it on the typewriter. Why not increase our efficiency by using this machine in our language department, when the commercial students are not using it ? It seems to be of most value in a Latin class, because of the limited vocabulary needed there. The ordinary phonograph, however, has long been used in the teaching of modern languages. The present article rests upon experience in the Latin class alone. The most important use in the Latin class is in vocabulary, inflections, and grammar. The record prepared by speaking into a tube in an ordinary tone can be heard by the entire class when a large flaring horn is attached by a rubber joint. This same record is afterward repeated to slow or absent pupils, or new pupils, either individually or in groups, with a single, or multiple, hearing device. By inclosing the machine in a tight box with only the hearing tube protruding, experiments are now being made to enable pupils to study with it in the back of the room while others are reciting in the room.