Influences of Thermo-Mechanical Properties of Polymeric Cords on Tires with and without Post-Cure Inflation

2002 ◽  
Vol 30 (3) ◽  
pp. 156-179 ◽  
Author(s):  
B. Chen

Abstract During manufacturing, tires are naturally cooled to room temperature after release from their molds. The manner in which the post-cure cooling process is performed can greatly influence a tires overall performance. As an effective procedure, post-cure inflation (PCI) had been commonly used during the post-cure cooling process to control dimensions and shapes of tires. However, since the introduction of dimensionally stable polyester as tire carcass cord material, PCI has been considered an unnecessary step and has been eliminated from some tire manufacturer's lines. By convention, tires manufactured with PCI are designated as PCI tires whereas tires manufactured without PCI are designated as no-PCI tires. As a result of the different loading histories experienced during the post-cure cooling process, PCI and no-PCI tires exhibit different behavioral aspects including dimensions and footprint shape. More specifically, when the same mold is used, the most prominent difference between PCI and no-PCI tires is the profile. No-PCI tires have smaller section widths and inflated crown radii than PCI tires due to the thermal shrinkage occurring in the cords during the post-cure cooling process. On the other hand, no-PCI tires exhibit more dimensional change than PCI tires when subjected to exercise. In this study, experimental passenger tires (235/75/R15) with and without PCI are built using the same curing mold, and a series of tests are conducted to establish the differences between these two kinds of tires. Meanwhile, material characterizations of the polyester tire cords used in the tire construction are conducted with various thermal-mechanical loading histories, and the influences of the post-cure cooling process on the cord properties are determined. Then an axisymmetric and a three-dimensional finite element model are constructed and the post-cure cooling processes with and without PCI are simulated. With the input of the cord material properties obtained through the material characterization, the numerical analyses successfully predict the tire dimensions, profile, and footprints for both PCI and no-PCI tires. The analytical results obtained are in agreement with the experimental measurements obtained from the experimental tires.

Author(s):  
A. Ibrahim ◽  
C.C. Berndt

Abstract The effect of WC-Co coating on the high cycle fatigue (HCF) behavior of SAE 12L14 steel and 2024-T4 aluminum was investigated. The fatigue tests were performed at room temperature and 370°C. The fatigue life distributions of specimens in the polished, grit blasted, peened, and coated conditions are presented as a function of the probability of failure. HVOF sprayed WC-Co coating has influenced the fatigue life of aluminum and steel. Factors contributing to this influence, which include grit blasting, elastic modulus, and residual stress, are discussed. A three-dimensional finite-element model (FEM) of the coated specimen was used to calculate the stress distribution across the coating and the substrate. The results of the analytical model are in good agreement with fatigue lives observed experimentally.


2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.


2021 ◽  
Vol 11 (5) ◽  
pp. 2225
Author(s):  
Fu Wang ◽  
Guijun Shi ◽  
Wenbo Zhai ◽  
Bin Li ◽  
Chao Zhang ◽  
...  

The steel assembled support structure of a foundation pit can be assembled easily with high strength and recycling value. Steel’s performance is significantly affected by the surrounding temperature due to its temperature sensitivity. Here, a full-scale experiment was conducted to study the influence of temperature on the internal force and deformation of supporting structures, and a three-dimensional finite element model was established for comparative analysis. The test results showed that under the temperature effect, the deformation of the central retaining pile was composed of rigid rotation and flexural deformation, while the adjacent pile of central retaining pile only experienced flexural deformation. The stress on the retaining pile crown changed little, while more stress accumulated at the bottom. Compared with the crown beam and waist beam 2, the stress on waist beam 1 was significantly affected by the temperature and increased by about 0.70 MPa/°C. Meanwhile, the stress of the rigid panel was greatly affected by the temperature, increasing 78% and 82% when the temperature increased by 15 °C on rigid panel 1 and rigid panel 2, respectively. The comparative simulation results indicated that the bending moment and shear strength of pile 1 were markedly affected by the temperature, but pile 2 and pile 3 were basically stable. Lastly, as the temperature varied, waist beam 2 had the largest change in the deflection, followed by waist beam 1; the crown beam experienced the smallest change in the deflection.


2007 ◽  
Vol 129 (6) ◽  
pp. 1028-1034 ◽  
Author(s):  
Liang Wang ◽  
Sergio Felicelli

A three-dimensional finite element model was developed to predict the temperature distribution and phase transformation in deposited stainless steel 410 (SS410) during the Laser Engineered Net Shaping (LENS™) rapid fabrication process. The development of the model was carried out using the SYSWELD software package. The model calculates the evolution of temperature in the part during the fabrication of a SS410 plate. The metallurgical transformations are taken into account using the temperature-dependent material properties and the continuous cooling transformation diagram. The ferritic and martensitic transformation as well as austenitization and tempering of martensite are considered. The influence of processing parameters such as laser power and traverse speed on the phase transformation and the consequent hardness are analyzed. The potential presence of porosity due to lack of fusion is also discussed. The results show that the temperature distribution, the microstructure, and hardness in the final part depend significantly on the processing parameters.


2013 ◽  
Vol 336-338 ◽  
pp. 760-763
Author(s):  
Hui Yue

A short explanation of the finite element method as a powerful tool for mathematical modeling is provided, and an application using constitutive modeling of the behavior of ligaments is introduced. Few possible explanations of the role of water in ligament function are extracted from two dimensional finite element models of a classical ligament. The modeling is extended to a three dimensional finite element model for the human anterior cruciate ligament. Simulation of ligament force in pitching motion of basketball player is studied in this paper.


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