Viscoelastic Loss Characteristics of Cord-Rubber Composites

1986 ◽  
Vol 14 (2) ◽  
pp. 75-101 ◽  
Author(s):  
F. Tabaddor ◽  
S. K. Clark ◽  
R. N. Dodge ◽  
J. M. Perraut

Abstract Calculated and experimentally generated complex moduli of tire cord-rubber composites are compared. Halpin-Tsai equations in complex form are defined and used to calculate the elastic and loss components of the composite moduli. Additionally, stress-strain relationships for bias ply composites are included. Experimental techniques consisted of prestrained cyclic tensile and torsional tests on tubular specimens. Composite properties of typical polyester and steel tire cord reinforcements were evaluated as functions of end count, cross-ply angle, and thickness of rubber filler between plies.

1982 ◽  
Vol 10 (1) ◽  
pp. 37-54 ◽  
Author(s):  
M. Kumar ◽  
C. W. Bert

Abstract Unidirectional cord-rubber specimens in the form of tensile coupons and sandwich beams were used. Using specimens with the cords oriented at 0°, 45°, and 90° to the loading direction and appropriate data reduction, we were able to obtain complete characterization for the in-plane stress-strain response of single-ply, unidirectional cord-rubber composites. All strains were measured by means of liquid mercury strain gages, for which the nonlinear strain response characteristic was obtained by calibration. Stress-strain data were obtained for the cases of both cord tension and cord compression. Materials investigated were aramid-rubber, polyester-rubber, and steel-rubber.


Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2534
Author(s):  
Sriharish Malebennur Nagaraja ◽  
Sven Henning ◽  
Sybill Ilisch ◽  
Mario Beiner

A comparative study focusing on the visco–elastic properties of two series of carbon black filled composites with natural rubber (NR) and its blends with butadiene rubber (NR-BR) as matrices is reported. Strain sweeps at different temperatures are performed. Filler network-related contributions to reinforcement (ΔG′) are quantified by the classical Kraus equation while a modified Kraus equation is used to quantify different contributions to dissipation (ΔGD″, ΔGF″). Results indicate that the filler network is visco-elastic in nature and that it is causing a major part of the composite dissipation at small and intermediate strain amplitudes. The temperature dependence of filler network-related reinforcement and dissipation contributions is found to depend significantly on the rubber matrix composition. We propose that this is due to differences in the chemical composition of the glassy rubber bridges connecting filler particles since the filler network topology is seemingly not significantly influenced by the rubber matrix for a given filler content. The underlying physical picture explains effects in both dissipation and reinforcement. It predicts that these glassy rubber bridges will soften sequentially at temperatures much higher than the bulk Tg of the corresponding rubber. This is hypothetically due to rubber–filler interactions at interfaces resulting in an increased packing density in the glassy rubber related to the reduction of free volume. From a general perspective, this study provides deeper insights towards the molecular origin of reinforcement and dissipation in rubber composites.


1985 ◽  
Vol 58 (4) ◽  
pp. 830-856 ◽  
Author(s):  
R. J. Cembrola ◽  
T. J. Dudek

Abstract Recent developments in nonlinear finite element methods (FEM) and mechanics of composite materials have made it possible to handle complex tire mechanics problems involving large deformations and moderate strains. The development of an accurate material model for cord/rubber composites is a necessary requirement for the application of these powerful finite element programs to practical problems but involves numerous complexities. Difficulties associated with the application of classical lamination theory to cord/rubber composites were reviewed. The complexity of the material characterization of cord/rubber composites by experimental means was also discussed. This complexity arises from the highly anisotropic properties of twisted cords and the nonlinear stress—strain behavior of the laminates. Micromechanics theories, which have been successfully applied to hard composites (i.e., graphite—epoxy) have been shown to be inadequate in predicting some of the properties of the calendered fabric ply material from the properties of the cord and rubber. Finite element models which include an interply rubber layer to account for the interlaminar shear have been shown to give a better representation of cord/rubber laminate behavior in tension and bending. The application of finite element analysis to more refined models of complex structures like tires, however, requires the development of a more realistic material model which would account for the nonlinear stress—strain properties of cord/rubber composites.


1993 ◽  
Vol 28 (2) ◽  
pp. 125-133 ◽  
Author(s):  
A Navarro ◽  
M W Brown ◽  
K J Miller

A simplified treatment is presented for the analysis of tubular specimens subject to in-phase tension-torsion loads in the elasto-plastic regime. Use is made of a hardening function readily obtainable from the uniaxial cyclic stress-strain curve and hysteresis loops. Expressions are given for incremental as well as deformation theories of plasticity. The reversals of loading are modelled by referring the flow equations to the point of reversal and calculating distances from the point of reversal using a yield critertion. The method has been used to predict the deformation response of in-phase tests on an En15R steel, and comparisons with experimental data are provided. The material exhibited a non-Masing type behaviour. A power law rule is developed for predicting multiaxial cyclic response from uniaxial data by incorporating a hysteretic strain hardening exponent.


1970 ◽  
Vol 185 (1) ◽  
pp. 1149-1158 ◽  
Author(s):  
K. Bitans ◽  
P. W. Whitton

Shear stress-shear strain curves for o.f.h.c. copper at room temperature have been obtained at constant shear strain rates in the range 1 to 103s-1, using thin walled tubular specimens in a flywheel type torsion testing machine. Results show that, for a given value of strain, the stress decreases when the rate of strain is increased. Moreover, the elastic portion of the stress-strain curve tends to disappear as the rate of strain is increased. It is postulated that these effects are due to the formation of adiabatic shear bands in the material when the given rate of strain is impressed rapidly enough. A special feature of the design of the testing machine used is the rapid application of the chosen strain rate.


1971 ◽  
Vol 44 (5) ◽  
pp. 1227-1248
Author(s):  
A. F. Blanchard

Abstract The theory of Part I is developed by application to filler reinforcement of NR and SBR. For unswollen but prestretched networks it quantifies entire stress-strain curves and applies new concepts of extensibility and strain hardening. Constraint of swelling is expressed by a constant Ø, termed linkage reinforcement, and by an effective hard fraction Cm per cm2 of compound. For rubber-filler swelling vc the modified Flory functions F(νc) in Part I need 3% correction.


2018 ◽  
Vol 92 (2) ◽  
pp. 219-236 ◽  
Author(s):  
Naresh D. Bansod ◽  
Bharat P. Kapgate ◽  
Pradip K. Maji ◽  
Anasuya Bandyopadhyay ◽  
Chayan Das

ABSTRACT Functionalization of non-polar ethylene propylene diene monomer (EPDM) rubber by melt grafting of maleic anhydride (MA) and in situ incorporation of sol–gel derived silica in the MA grafted EPDM has been done to prepare EPDM/silica composites to use dual benefits of both the approaches, which results in adequate rubber–filler compatibility, good filler dispersion, and enhanced composite properties. Controlled growth of silica up to 25 parts per hundred rubber (phr) is carried out with the solution sol–gel process using tetraethoxysilane (TEOS) as a silica precursor. Mechanical and dynamical properties of the composites are found to improve consistently as silica content increases. Furthermore, treatment of maleic anhydride grafted EPDM by γ-aminopropyltrimethoxysilane (γ-APS) results in remarkable improvement in composite properties even at the same silica content. This is attributed to the generation of uniformly dispersed spherically shaped nanosilica throughout the rubber matrix as observed in a transmission electron microscopic (TEM) study. This contributes to enhanced crosslinking density and improved rubber–filler interaction. In fact, the reinforcement effect brought by in situ silica relative to unmodified in situ silica/EPDM composites is found to be much higher than that reported in recent work on EPDM/in situ silica composites even with higher silica loading. The mechanical, rheological, and dynamic mechanical behaviors of all the composites are evaluated and compared in detail.


1981 ◽  
Vol 54 (1) ◽  
pp. 72-90 ◽  
Author(s):  
D. C. Prevorsek ◽  
R. K. Sharma

Abstract Dynamic mechanical measurements have been carried out on samples of rubber and PET cord-rubber composites, with and without adhesive, as a function of strain amplitude, temperature, pretension, angle of strain application and time of cycling. The results show that mechanical loss and dynamic modulus depend on these variables as well as the presence and type of adhesive at the cord-rubber interface. Based on these results, we conclude that adhesion plays a significant role in the viscoelastic properties of a composite and it is an important factor along with the properties of components in the analysis of tire performance in terms of composite properties. This study clearly shows that the maximum adhesion may not be the optimum adhesion in tire technology. The most relevant question, i.e., the determination of the optimum level of adhesion for a specific tire, however, remains unanswered. The viscoelastic properties of the composites decrease with time of cycling but the rate of decrease depends upon the level of adhesion in the starting material. This result could be important in the development of a more realistic dynamic adhesion test. Attempts to use the viscoelastic experiments with small amplitude, high frequency strain to determine the onset of fracture in the composite specimen appears to be promising. Work is in progress to determine the potential of this method in the analysis of adhesion.


Sign in / Sign up

Export Citation Format

Share Document