Strength Evaluation of Polymer Composite Spur Gear by Finite Element Analysis

2008 ◽  
Author(s):  
Mohammad Robiul Hossan ◽  
Zhong Hu
Keyword(s):  
Finite Element ◽  
Polymer Composite ◽  
Volume Fraction ◽  
Gear Tooth ◽  
Axial Stress ◽  
High Stress ◽  
Element Model ◽  
Simulation Method ◽  
Spur Gear ◽  
Element Analysis

Modern advanced polymer composite materials have opened a new level of noiseless, lubricant free, high resilience and precision gearing in power and motion transmission. The proper understanding and evaluation of gear strength and performance is an important prerequisite for any reliable application. In this paper, a 20% short glass fiber reinforced nylon66 spur gear fabricated by injection molding has been carefully investigated. A three-dimensional finite element model was used to simulate the multi-axial stress-strain behaviors of a gear tooth under the dynamic load for a complete working cycle with a special geometry, operating condition, fiber orientation and volume fraction. The strength of composite gears has been compared with isotropic un-reinforced nylon66 and steel gears. The tooth root region of a gear which usually experiences high stress and potential to failure has been carefully investigated. This computer simulation method can be used as a useful tool for evaluating strength and predicting failure of the polymer composite gears.

scholarly journals A Method of Selecting Grid Size to Account for Hertz Deformation in Finite Element Analysis of Spur Gears

1982 ◽  
Vol 104 (4) ◽  
pp. 759-764 ◽  
Author(s):  
J. J. Coy ◽  
C. Hu-Chih Chao
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Gear Tooth ◽  
Spur Gear ◽  
Grid Size ◽  
Spur Gears ◽  
Element Analysis ◽  
Element Size ◽  
Full Effect ◽  
The Finite Element Analysis

A method of selecting grid size for the finite element analysis of gear tooth deflection is presented. The method is based on a finite element study of two cylinders in line contact, where the criterion for establishing element size was that there be agreement with the classic Hertzian solution for deflection. Many previous finite element studies of gear tooth deflection have not included the full effect of the Hertzian deflection. The present results are applied to calculate deflection for the gear specimen used in the NASA spur gear test rig. Comparisons are made between the present results and the results of two other methods of calculation. The results have application in design of gear tooth profile modifications to reduce noise and dynamic loads.

Investigation of Residual Stress Development During Swage Autofrettage, Using Finite Element Analysis

2009 ◽  
Author(s):  
Michael C. Gibson ◽  
Amer Hameed ◽  
John G. Hetherington
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Axial Stress ◽  
Slope Angle ◽  
Subsequent Development ◽  
Element Model ◽  
Pressure Vessels ◽  
Element Analysis ◽  
Reverse Yielding

Swaging is one method of autofrettage, a means of pre-stressing high-pressure vessels to increase their fatigue lives and load bearing capacity. Swaging achieves the required deformation through physical interference between an oversized mandrel and the bore diameter of the tube, as it is pushed through the tube. A Finite Element model of the swaging process was developed, in ANSYS, and systematically refined, to investigate the mechanism of deformation and subsequent development of residual stresses. A parametric study was undertaken, of various properties such as mandrel slope angle, parallel section length and friction coefficient. It is observed that the axial stress plays a crucial role in the determination of the residual hoop stress and reverse yielding. The model, and results obtained from it, provides a means of understanding the swaging process and how it responds to different parameters. This understanding, coupled with future improvements to the model, potentially allows the swaging process to be refined, in terms of residual stresses development and mandrel driving force.

Simulation of Microstructure Evolution and Deformation Behavior for Dual-Phase Steel by Multi-Phase-Field Method and Elastoplastic Finite Element Method

2013 ◽  
Vol 7 (1) ◽  
pp. 16-23 ◽  
Author(s):  
Akinori Yamanaka ◽  
◽  
Tomohiro Takaki ◽  
Keyword(s):  
Finite Element ◽  
Phase Field ◽  
Deformation Behavior ◽  
Volume Fraction ◽  
Simulation Method ◽  
Phase Field Method ◽  
Element Analysis ◽  
Dp Steel ◽  
Α Phase ◽  
Multi Phase

A coupled simulation method is developed by using a Multi-Phase-Field (MPF) method that is recognized as a powerful numerical method for simulating microstructure formation in material and ElastoPlastic Finite Element Analysis (EP-FEA) based on a homogenization method. We apply the developed simulation method to investigate the deformation behavior of DP steel that includes various volume fractions and morphologies of the ferrite (α) phase. To obtain morphological information on the α phase of DP steel, we performed MPF simulation of austenite-to-ferrite (γ → α) transformation during continuous cooling transformation. MPF simulation gives us the digital image of the distribution of the simulated α phase. Furthermore, we model the representative volume element, which describes the DP microstructure, on the basis of the obtained morphology of the α phase, and perform tension-compression testing of DP steel, including the simulated α phase. Through these simulations, it is confirmed that the developed simulation method enables us to clarify the effect of the volume fraction and the configuration of the α phase on macroscopic deformation behavior of DP steel, such as the Bauschinger effect.

Investigation of Broken Cut Spikes on Elastic Fastener Tie Plates Using an Integrated Simulation Method

2018 ◽  
Author(s):  
Yin Gao ◽  
Mike McHenry ◽  
Brad Kerchof
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Simulation Method ◽  
Operating Conditions ◽  
Analysis Model ◽  
Element Analysis ◽  
Integrated Simulation ◽  
Multibody Model ◽  
Track System ◽  
High Degree

Cut spike fasteners, used with conventional AREMA rolled tie plates and solid sawn timber ties, are the most common tie and fastener system used on North American freight railroads. Cut spikes are also used to restrain tie plates that incorporate an elastic rail fastener — that is, an elastic clip that fastens the rail to the tie plate. Elastic fasteners have been shown to reduce gage widening and decrease the potential for rail roll compared to cut spike-only systems. For this reason, elastic fastener systems have been installed in high degree curves on many railroads. Recent observations on one Class I railroad have noted broken cut spikes when used with these types of tie plates in mountainous, high degree curve territory. Broken screw spikes and drive spikes on similar style plates have also been observed. In this paper, a simulation method that integrates a vehicle-track system dynamics model, NUCARS®, with a finite element analysis model is used to investigate the root causes of the broken spikes. The NUCARS model consists of a detailed multibody train, wheel-rail contact parameters, and track model that can estimate the dynamic loading environment of the fastening system. For operating conditions in tangent and curve track, this loading environment is then replicated in a finite element model of the track structure — ties, tie plates, and cut spikes. The stress contours of the cut spikes generated in these simulations are compared to how cut spikes have failed in revenue service. The tuning and characterization of both the vehicle dynamics multibody model and the finite element models are presented. Additionally, the application of this approach to other types of fastening systems and spike types is discussed. Preliminary results have identified a mechanism involving the dynamic unloading of the tie plate-to-tie interface due to rail uplift ahead of the wheel and the resulting transfer of net longitudinal and lateral forces into the cut spikes. Continued analysis will attempt to confirm this mechanism and will focus on the severity of these stresses, the effect of increased grade, longitudinal train dynamics, braking forces, and curvature.

A Finite Element Approach for Study of Wave Attenuation Characteristics of Epoxy Polymer Composite

2018 ◽  
Author(s):  
Shank S. Kulkarni ◽  
Alireza Tabarraei ◽  
Pratik P. Ghag
Keyword(s):  
Finite Element ◽  
Polymer Composite ◽  
Polymer Matrix ◽  
Wave Attenuation ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Element Model ◽  
Loading Frequency ◽  
Macroscopic Properties ◽  
Attenuation Characteristics

The properties of the inclusions, viz. size, shape, and distribution significantly affect macroscopic properties of a polymer composite. Finite element (FE) modeling provides a viable approach for investigating the effects of the inclusions on the macroscopic properties of the polymer composite. In this paper, finite element method is used to investigate ultrasonic wave propagation in polymer matrix composite with a dispersed phase of inclusions. The finite element models are made up of three phases; viz. the polymer matrix, inclusions (micro constituent), and interphase zones between the inclusions and the polymer matrix. The analysis is performed on a three dimensional finite element model and the attenuation characteristics of ultrasonic longitudinal waves in the matrix are evaluated. The attenuation in polymer composite is investigated by changing the size, volume fraction of inclusions, and addition of interphase layer. The effect of loading frequency of the wave on the attenuation characteristics is also studied by varying the frequency in the range of 1–4 MHz. Results of the test revealed that higher volume fraction of inclusions gave higher attenuation in the polymer composite as compared to the lower volume fraction model. Smaller size of inclusions are preferred over larger size as they give higher wave attenuation. It was found that the attenuation characteristics of the polymer composite are better at higher frequencies as compared to lower frequencies. It is also concluded that the interphase later plays a significant role in the attenuation characteristics of the composite.

scholarly journals Effects of Rim Thickness on Spur Gear Bending Stress

1994 ◽  
Vol 116 (4) ◽  
pp. 1157-1162 ◽  
Author(s):  
G. D. Bibel ◽  
S. K. Reddy ◽  
M. Savage ◽  
R. F. Handschuh
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Power ◽  
Design Parameter ◽  
Gear Tooth ◽  
Spur Gear ◽  
Bending Stress ◽  
Element Analysis ◽  
Bending Stresses

Thin rim gears find application in high-power, lightweight aircraft transmissions. Bending stresses in thin rim spur gear tooth fillets and root areas differ from the stresses in solid gears due to rim deformations. Rim thickness is a significant design parameter for these gears. To study this parameter, a finite element analysis was conducted on a segment of a thin rim gear. The rim thickness was varied and the location and magnitude of the maximum bending stresses reported. Design limits are discussed and compared with the results of other researchers.

The Role of Fluid Dynamics in Distributing Ankle Stresses in Anatomic and Injured States

2016 ◽  
Vol 37 (12) ◽  
pp. 1343-1349 ◽  
Author(s):  
Kamran S. Hamid ◽  
Aaron T. Scott ◽  
Benedict U. Nwachukwu ◽  
Kerry A. Danelson
Keyword(s):  
Finite Element ◽  
Synovial Fluid ◽  
Principal Stress ◽  
Maximum Stress ◽  
High Stress ◽  
Distal Tibia ◽  
Element Model ◽  
Maximum Principal Stress ◽  
Ankle Injuries ◽  
Element Analysis

Background: In 1976, Ramsey and Hamilton published a landmark cadaveric study demonstrating a dramatic 42% decrease in tibiotalar contact area with only 1 mm of lateral talar shift. An increase in maximum principal stress of at least 72% is predicted based on these findings though the delayed development of arthritis in minimally misaligned ankles does not appear to be commensurate with the results found in dry cadaveric models. We hypothesized that synovial fluid could be a previously unrecognized factor that contributes significantly to stress distribution in the tibiotalar joint in anatomic and injured states. Methods: As it is not possible to directly measure contact stresses with and without fluid in a cadaveric model, finite element analysis (FEA) was employed for this study. FEA is a modeling technique used to calculate stresses in complex geometric structures by dividing them into small, simple components called elements. Four test configurations were investigated using a finite element model (FEM): baseline ankle alignment, 1 mm laterally translated talus and fibula, and the previous 2 bone orientations with fluid added. The FEM selected for this study was the Global Human Body Models Consortium–owned GHBMC model, M50 version 4.2, a model of an average-sized male (distributed by Elemance, LLC, Winston-Salem, NC). The ankle was loaded at the proximal tibia with a distributed load equal to the GHBMC body weight, and the maximum principal stress was computed. Results: All numerical simulations were stable and completed with no errors. In the baseline anatomic configuration, the addition of fluid between the tibia, fibula, and talus reduced the maximum principal stress computed in the distal tibia at maximum load from 31.3 N/mm2 to 11.5 N/mm2. Following 1 mm lateral translation of the talus and fibula, there was a modest 30% increase in the maximum stress in fluid cases. Qualitatively, translation created less high stress locations on the tibial plafond when fluid was incorporated into the model. Conclusions: The findings in this study demonstrate a meaningful role for synovial fluid in distributing stresses within the ankle that has not been considered in historical dry cadaveric studies. The increase in maximum stress predicted by simulation of an ankle with fluid was less than half that projected by cadaveric data, indicating a protective effect of fluid in the injured state. The trends demonstrated by these simulations suggest that bony alignment and fluid in the ankle joint change loading patterns on the tibia and should be accounted for in future experiments. Clinical Relevance: Synovial fluid may play a protective role in ankle injuries, thus delaying the onset of arthritis. Reactive joint effusions may also function to additionally redistribute stresses with higher volumes of viscous fluid.

Investigation of Residual Stress Development During Swage Autofrettage, Using Finite Element Analysis

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
Michael C. Gibson ◽  
Amer Hameed ◽  
John G. Hetherington
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Axial Stress ◽  
Slope Angle ◽  
Subsequent Development ◽  
Element Model ◽  
Pressure Vessels ◽  
Element Analysis ◽  
Reverse Yielding

Swaging is one method of autofrettage, a means of prestressing high-pressure vessels to increase their fatigue lives and load bearing capacity. Swaging achieves the required deformation through physical interference between an oversized mandrel and the bore diameter of the tube, as it is pushed through the tube. A finite element model of the swaging process was developed, in ansys, and systematically refined, to investigate the mechanism of deformation and subsequent development of residual stresses. A parametric study was undertaken, of various properties such as mandrel slope angle, parallel section length, and friction coefficient. It is observed that the axial stress plays a crucial role in the determination of the residual hoop stress and reverse yielding. The model, and results obtained from it, provides a means of understanding the swaging process and how it responds to different parameters. This understanding, coupled with future improvements to the model, potentially allows the swaging process to be refined, in terms of residual stresses development and mandrel driving force.

Finite element analysis of stress around a sternum screw used to prevent sternal dehiscence after heart surgery

2002 ◽  
Vol 216 (5) ◽  
pp. 315-321 ◽  
Author(s):  
R S Jutley ◽  
M A Watson ◽  
D E T Shepherd ◽  
D W L Hukins
Keyword(s):  
Finite Element ◽  
Contact Stress ◽  
Heart Surgery ◽  
High Stress ◽  
Median Sternotomy ◽  
Element Model ◽  
Element Analysis ◽  
Sternal Dehiscence ◽  
Cortical Shell ◽  
The Wire

The sternum screw has been proposed as a means of preventing sternal dehiscence, following heart surgery, by increasing the contact area between the wire used to close the median sternotomy and the surrounding bone; as a result, the contact stress is reduced. A finite element model was constructed of a cylindrical wire or screw passing through a block of sternum which consisted of cancellous bone sandwiched within a cortical shell. The thickness of the cortical shell and the material properties of bone were varied between reasonable values. The stress distribution in the sternum was calculated for each model when the wire was subjected to a tension (250 N) which would be required for six wires to withstand a strong cough (40kPa). Results were validated by comparison with a simple analytical model in which the bone and wire were considered incompressible. They show that the screw reduces the contact stress to almost one-seventh of its value when wire is used alone. Contact stresses are especially high if the cortical shell is thin. The high stress in the bone around a screw falls off within a few millimetres. As a result, no problems are anticipated in placing six screws in each half-sternum so that the sternotomy may be closed with the usual six wires.

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