A New Design of Tooth Profiles Increases Synchronous Belt’s Fatigue Life

Author(s):  
Jianhua Guo ◽  
Hongyuan Jiang ◽  
Gang Han ◽  
Hui Yan

Synchronous belt and its driving pulley have non-conjugate tooth profiles. Because of non-conjugate motion and polygon effect, interference occurs during incomplete meshing, resulting in excessive wear and tear at tooth-root, which are the main forms of failure of synchronous belts. Tooth cracking also results from uneven stress distribution and/or increased maximal stress. In addition to discovering better materials to increase the strength of the belt’s teeth, optimization of the geometry of tooth profiles of belt and pulley to decrease the maximum tooth-root stress and to reduce interference during meshing is critical in improving the carrying capacity and increasing the belt’s life span. In the present study we proposed a new design of synchronous belt’s and pulley’s tooth profiles, modifying several key geometric parameters commonly used in synchronous belts’ designs. Applying the conformal mapping function and the theory of plane elasticity we systemically investigated the distribution of stress and distortion at the belt’s and pulley’s teeth of varying geometric parameters and analyzed the interference during meshing using an approach to investigating tooth profiles of non-constant pitch diameter. Finite Element Analysis showed that with the same load the maximum principal stress values of belt teeth in complete meshing in our design (STSB) were 54.4% and 67.8% of that of HTD (by Uniroyal) and STPD (by Good Year) belts with an 8 mm pitch commonly used in automobiles, respectively. The uneven distribution of stress along the edge of tooth profile was reduced, and the interference during meshing minimized with our design. We then experimentally tested belts made of the same materials with the three designs manufactured by the same factory. The belts were tested in the enclosed type of testing machine for synchronous belt’s fatigue-life, power = 6.5 kW and speed = 1500 r/min with test belt tension at 400 N. The fatigue lives of the belts (n = 5 each group) were 988 ± 36, 439 ± 21 and 665 ± 22 hours (mean ± SD) for STSB, HTD and STPD belts (p<0.0001), respectively, demonstrating the superiority of our design. We anticipate that the new design will have wide applications not limited to the automobile industry.

Author(s):  
Xiao-Dong Bai ◽  
Yun-Peng Zhao ◽  
Guo-Hai Dong ◽  
Chun-Wei Bi

The failure risk of fish cages has increased in the harsher environmental conditions as fish farms have moved into the open sea in recent years. Fatigue failure is an important limit state for the floating system of the fish cage under the long-term action of waves. This study is presented to investigate the applicable probability density function for estimating fatigue life of the high-density polyethylene (HDPE) floating collars. The stress response of the floating collars system in random wave is firstly analyzed based on the finite element analysis combined with a hydrodynamic model. The stress histories of floating collars under each sea state are counted using the rainflow method as a benchmark for fatigue frequency domain analysis. The distribution of stress range was fitted by various probability density functions including Rayleigh, Weibull, Gamma and generalized extreme value (GEV) distributions. Comparisons of the estimated fatigue life using different distributions with rainflow statistic results were performed. Results indicate fatigue estimation based on the GEV and Gamma distributions by removing the negligible low stress range give much more accurate fatigue damage results of the short-term stress range distribution. While Weibull distribution overestimates the fatigue lifetime of the floating collar based on the short-term distribution of stress ranges.


Author(s):  
S. Nallusamy ◽  
N. Manikanda Prabu ◽  
K. Balakannan ◽  
Gautam Majumdar

The vehicle may be towed without the engine but it is not possible without the wheels. Road wheel is a significant structural member of the vehicular suspension system that supports the static and dynamic loads encountered during vehicle operation. As in the case of an automobile wheel maximum load is applied on the alloy wheel. Proper analysis of the alloy wheel plays a significant role for the safety of the passenger cars. Alloy wheels which are intended for normal use on passenger cars, undergo three tests and have to pass before going into the production: Dynamic Cornering Fatigue Test, Dynamic Radial Fatigue Test and Impact Test. Most of aluminium alloy wheels manufacturing companies have done several testing of their product however information of their method on simulation test is often kept limited. During a part of research a static and fatigue analysis of aluminum alloy wheel A356.0 was carried out using FEA package. The 3-D model was imported from CATIA into ANSYS using the appropriate format. Finite element analysis (FEA) is carried out by simulating the test conditions to analyze stress distribution and fatigue life of the aluminium alloy wheel rim of passenger car. Experimental analyses are carried out by radial fatigue testing machine for evaluation of fatigue life under influence of camber angle. The test indicates that integrating FEA and nominal stress method is a good and efficient method to predict alloy wheels fatigue life. In this paper by observing the results of both static and dynamic analysis the aluminium alloy is suggested as better material.


2019 ◽  
Vol 893 ◽  
pp. 1-5 ◽  
Author(s):  
Eui Soo Kim

Pressure vessels are subjected to repeated loads during use and charging, which can causefine physical damage even in the elastic region. If the load is repeated under stress conditions belowthe yield strength, internal damage accumulates. Fatigue life evaluation of the structure of thepressure vessel using finite element analysis (FEA) is used to evaluate the life cycle of the structuraldesign based on finite element method (FEM) technology. This technique is more advanced thanfatigue life prediction that uses relational equations. This study describes fatigue analysis to predictthe fatigue life of a pressure vessel using stress data obtained from FEA. The life prediction results areuseful for improving the component design at a very early development stage. The fatigue life of thepressure vessel is calculated for each node on the model, and cumulative damage theory is used tocalculate the fatigue life. Then, the fatigue life is calculated from this information using the FEanalysis software ADINA and the fatigue life calculation program WINLIFE.


Author(s):  
Xian-Kui Zhu ◽  
Rick Wang

Mechanical dents often occur in transmission pipelines, and are recognized as one of major threats to pipeline integrity because of the potential fatigue failure due to cyclic pressures. With matured in-line-inspection (ILI) technology, mechanical dents can be identified from the ILI runs. Based on ILI measured dent profiles, finite element analysis (FEA) is commonly used to simulate stresses and strains in a dent, and to predict fatigue life of the dented pipeline. However, the dent profile defined by ILI data is a purely geometric shape without residual stresses nor plastic deformation history, and is different from its actual dent that contains residual stresses/strains due to dent creation and re-rounding. As a result, the FEA results of an ILI dent may not represent those of the actual dent, and may lead to inaccurate or incorrect results. To investigate the effect of residual stress or plastic deformation history on mechanics responses and fatigue life of an actual dent, three dent models are considered in this paper: (a) a true dent with residual stresses and dent formation history, (b) a purely geometric dent having the true dent profile with all stress/strain history removed from it, and (c) a purely geometric dent having an ILI defined dent profile with all stress/strain history removed from it. Using a three-dimensional FEA model, those three dents are simulated in the elastic-plastic conditions. The FEA results showed that the two geometric dents determine significantly different stresses and strains in comparison to those in the true dent, and overpredict the fatigue life or burst pressure of the true dent. On this basis, suggestions are made on how to use the ILI data to predict the dent fatigue life.


2011 ◽  
Vol 86 ◽  
pp. 566-569
Author(s):  
Jian Hua Guo ◽  
Hong Yuan Jiang ◽  
Dong Sheng Li

Conformal mapping with complex function based on plane elasticity mechanics is an analytical method for resolving stress and displacement at any point of a half-plane domain. Using complex function conformal mapping method in this article we investigated the relationship between load on tooth surface and maximum stress at tooth root for calculating the maximum compressive stress on the opposite side of working flank and maximum tensile stress on working flank side when loads are applied to tooth top and root of working flank side, respectively. The maximum tensile and compressive stress at the tooth root are the main forces that cause fatigue cracking of the tooth root, which may extend along the elastomer compound-cord interface resulting in shear cracking of the belt tooth. The results of our calculation reveal the mechanisms whereby tooth shear cracking causes fatigue failure of synchronic belt, which are consistent with the experimental research results of Lizuka.


2001 ◽  
Vol 42 (5) ◽  
pp. 809-813 ◽  
Author(s):  
Young-Eui Shin ◽  
Kyung-Woo Lee ◽  
Kyong-Ho Chang ◽  
Seung-Boo Jung ◽  
Jae Pil Jung

2000 ◽  
Vol 123 (1) ◽  
pp. 150-154
Author(s):  
John H. Underwood ◽  
Michael J. Glennon

Laboratory fatigue life results are summarized from several test series of high-strength steel cannon breech closure assemblies pressurized by rapid application of hydraulic oil. The tests were performed to determine safe fatigue lives of high-pressure components at the breech end of the cannon and breech assembly. Careful reanalysis of the fatigue life tests provides data for stress and fatigue life models for breech components, over the following ranges of key parameters: 380–745 MPa cyclic internal pressure; 100–160 mm bore diameter cannon pressure vessels; 1040–1170 MPa yield strength A723 steel; no residual stress, shot peen residual stress, overload residual stress. Modeling of applied and residual stresses at the location of the fatigue failure site is performed by elastic-plastic finite element analysis using ABAQUS and by solid mechanics analysis. Shot peen and overload residual stresses are modeled by superposing typical or calculated residual stress distributions on the applied stresses. Overload residual stresses are obtained directly from the finite element model of the breech, with the breech overload applied to the model in the same way as with actual components. Modeling of the fatigue life of the components is based on the fatigue intensity factor concept of Underwood and Parker, a fracture mechanics description of life that accounts for residual stresses, material yield strength and initial defect size. The fatigue life model describes six test conditions in a stress versus life plot with an R2 correlation of 0.94, and shows significantly lower correlation when known variations in yield strength, stress concentration factor, or residual stress are not included in the model input, thus demonstrating the model sensitivity to these variables.


Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1589
Author(s):  
Rongjia Li ◽  
Wang Xu ◽  
Dalin Zhang

The aircraft electro-thermal anti-icing system that can guarantee flight safety may be affected by periodic heating and cyclic aerodynamic force during long-term flight missions, which seems to be a potential threat to ice protection. This paper aims to investigate the impacts of thermal and mechanical cycles on heating elements of the electro-thermal anti-icing system. Specimens were manufactured with CFRP (carbon fiber reinforced polymer) laminated composite, glass fiber prepreg and copper screen, in which sprayable metal film (SMF) was embedded as the heating element. The study focuses on electric resistance variation of SMF and functional fatigue life under the cycling load. Thermal cycling tests were carried out in an insulated chamber where the specimens were heated up to 80 °C and then cooled down to −55 °C for 1000 cycles. Mechanical cycling tests were conducted on a fatigue testing machine where the specimens were imposed on tension-compression loading for 106 cycles. Results showed that the electric resistance of SMF increased with the number of loading cycles. The resistance was increased by 20% and the heating power was decreased by 16.67% after 1000 thermal cycles. During the mechanical cycling tests, it was found that the heating element was destructed before the structural failure, which indicated that the fatigue life of function was lower than that of the structure.


2019 ◽  
Vol 17 (1) ◽  
pp. 25-40 ◽  
Author(s):  
Hafida Kahoul ◽  
Samira Belhour ◽  
Ahmed Bellaouar ◽  
Jean Paul Dron

Purpose This paper aims to present the fatigue life behaviour of upper arm suspension. The main objectives are to predict the fatigue life of the component and to identify the critical location. In this analysis, three aluminium alloys were used for the suspension, and their fatigue life was compared to select the suitable material for the suspension arm. Design/methodology/approach CAD model was prepared using Solid Works software, and finite element analysis was done using ANSYS 14.0 software by importing the Parasolid file to ANSYS. The model is subjected to loading and boundary conditions; the authors consider a vertical force with constant amplitude applied at the bushing that connected to the tire, the others two bushing that connected to the body of the car are constraint. Tetrahedral elements given enhanced results as compared to other types of elements; therefore, the elements (TET 10) are used. The maximum principal stress was considered in the linear static analysis, and fatigue analysis was done using strain life approach. Findings Life and damage are evaluated and the critical location was considered at node 63,754. From the fatigue analysis, aluminium alloys 7175-T73 (Al 90%-Zn 5.6%-Mg 2.5% -… …) and 2014-T6 (Al 93.5%-Cu 4.4%-Mg 0.5%… …) present a similar behaviour as compared to 6061-T6 (Al 97.9%-Mg 1.0%-Si 0.6%… … .); in this case of study, these lather are considered to be the materials of choice to manufacture the suspension arms; but 7175-T73 aluminium alloys remain the material with a better resistance to fatigue. Originality/value By the finite element analysis method and assistance of ANSYS software, it is able to analyse the different car components from varied aspects such as fatigue, and consequently save time and cost. For further research, the experimental works under controlled laboratory conditions should be done to determine the validation of the result from the software analysis.


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