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A known factor which limits the life cycle performance of automotive front-end accessory serpentine belt drive is cracking of the elastomer located in the rib tip. In this paper, fracture mechanics was used to study crack growth in belt rib. Tearing energy and J-integral were employed to characterize the fracture behavior of rubber compound. A global-local strategy was adopted to predict the crack initiation in V-ribbed belt rib. The global finite element model of the belt was created with relatively coarse mesh. The local model with fine mesh around the crack tip region was used to evaluate the J-integral. The J-integral computed using finite element analysis was compared with the threshold value found by experiments to predict the onset of crack initiation in belt rib.

A general three-dimensional finite element model was built to simulate the tracking conditions inherent in automotive front-end accessory drives, specifically, serpentine V-ribbed belt drives. Commercial finite element code ABAQUS was used for the simulation. The analysis is based on a hyper-elastic material model for the belt, and includes the effect of the reinforced cords and fibers in the rubber compound. The model can be used to study different parameters of the belt drive system such as rib number, pulley misalignment, drive wrap angle and drive speed. Experiments were used to validate the finite element model. Belt misalignment force of two, four and six ribbed belts under different misalignment conditions was obtained from experiment and compared with the results from the finite element model. Good correlation between these results brings confidence to the finite element model. Finally, typical FEA simulation results for a six-ribbed belt are presented.

A three-dimensional dynamic finite element model was built to study the stress distribution in V-ribbed belts. Commercial finite element code ABAQUS was used for the simulation. The model consists of a pulley and a segment of V-ribbed belt in contact with the pulley. Different belt pulley tracking configurations can be obtained by varying the pulley diameter and the belt wrap angle. Belt tension and pulley rotating speed can be controlled by the load and boundary conditions. Both driving and driven pulley can be modeled by applying different sets of load and boundary conditions. Rubber is modeled as hyperelastic material. Reinforcing cord and fabric are modeled as rebar defined in ABAQUS. Emphasis was put on the belt rib tip stress because it causes belt wear and belt rib fatigue cracking. The stress at the belt rib tips depends on tension in the belt, pulley contact friction coefficients, rib rubber properties, pulley diameter and belt wrap angle.

This paper investigates the effect of ambient temperature on the performance characteristics of an automotive poly-rib belt operating in an under-the-hood temperature environment. A three-dimensional dynamic finite element model consisting of a driver pulley, a driven pulley, and a complete V-ribbed belt was constructed. Belt tension and rotational speed were controlled by means of loading and boundary inputs. Belt construction accounts for three different elastomeric compounds and a single layer of helical wound reinforcing cord. Rubber was considered as hyperelastic material. Cord is linear elastic. The material model was implemented in ABAQUS/Explicit for the simulation. Analysis was focused on rib flank and tip since stress concentrations in these regions are known to contribute to crack initiation and fatigue failure.

A quarter section of a circular torus with both ends fixed is used to geometrically model hydraulic hose commonly found in applications requiring directional change in fluid flow. Thin shell differential equations of equilibrium are solved with curvatures based on Donnell assumptions. Classical laminate analysis is used to determine peak layer stress for both wire reinforced braided and spiral elastomeric hose. Circumferential and axial stress intensity factors are documented for pressure, bend radius and hose size. Historical minimum bend guidelines obtained by testing and experience are shown to correlate satisfactorily with theoretical stress results.

Maximum wire stress in helically wound pressurized elastomeric spiraled hose subjected to large flexural bending is mathematically analyzed. Solution approach is to superimpose the state of stress of a straight pressurized hose and an unloaded hose bent to a small radius. Since helical wires during pressurization change both radial position and angle, stresses due to a change of radii of curvature and torsion are included along with axial stress. Bending stress is obtained by decomposing the hose into its basic element, a single helical wire, and applying a pure bending moment to it. Hose bending stiffness is approximated as a summation of the bending stiffness of each wire plus individual bending stiffness of the elastomeric cylinders representing the tube, jacket, and cover, respectively. Bending stiffness test data is provided for both four and six spiraled hose with inside diameters 1.0 and 1.25 inches (25.4 and 31.8 mm).