Automation of gearbox design

AbstractIn order to respond to a shortened development time of today’s transmission systems, the automation of certain steps in the design process is essential for ensuring an efficient development process. Computer-aided tools are widely used for analyzing given design configurations because standardized methods are available to evaluate the load carrying capacity of all key components of a simple gear train, namely bearings, shafts and gears. At an early stage of development, requirements and restrictions need to be synthesized to design concepts. During this step, engineers typically rely on their experience and proven practice. Design optimization usually is achieved through an iterative and time-consuming process of analyzing and tuning towards an optimization objective. In this paper a time-saving, automated and systematic method for the design of weight optimized helical gearboxes is proposed. The underlying method has been derived from both, norms and guidelines, which exist for the design and layout of shafts, bearings and gear wheel bodies. Starting with only few input parameters, a detailed shaft geometry with different diameter sections can be derived. A discrete set of values from standard tables and rolling bearing catalogs represents the method’s framework for all realizable shaft diameters in each section. A mixed integer nonlinear optimization problem results from the interdependence between these distinct values. For this purpose, a systematic iterative approach has been developed and implemented in an established design program for gearbox systems. The algorithm uses the results drawn from an analytical calculation of the shaft load carrying capacity to directly adjust the shaft’s diameter and length values. The dimensioning of the wheel body, the service life calculation of rolling element bearings and the selection of specific machine elements are embedded in a systematic sequence. As a result, the model is capable to work out a weight-optimized gearbox that consists of gear meshes, shafts and bearings, taking all three components into consideration at a time.

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Isothermal hydrodynamic pressure and load carrying capacity of parallel rough surfaces based on FFT techniques

Transactions of the Canadian Society for Mechanical Engineering ◽

10.1139/tcsme-2019-0174 ◽

2020 ◽

Vol 44 (4) ◽

pp. 602-612

Author(s):

Wan Ma

Keyword(s):

Carrying Capacity ◽

Hydrodynamic Lubrication ◽

Rough Surfaces ◽

Hydrodynamic Pressure ◽

Radius Of Curvature ◽

Real Surface ◽

Load Carrying Capacity ◽

Time Saving ◽

Lubricated Contacts ◽

Load Carrying

In lubricated contacts, the component macrogeometry (radius of curvature) determines the pressure generation, and the surface microgeometry (i.e., roughness) alters it somewhat. However, for parallel surfaces, the microgeometry completely determines the hydrodynamic lubrication. This paper extends earlier work to numerically solve the isothermal hydrodynamic pressure generation and load carrying capacity (LCC) of surfaces with more complicated roughness features. A fast Fourier transform (FFT)-based method is described to quickly obtain the pressure distribution. The method is applicable to both real surface topographies and artificially generated rough surfaces. Results show that it enables one to predict the hydrodynamic pressure, when cavitation is negligible. The relative error of the LCC over the central domain is smaller than 8% and a 500× time saving, compared with the numerical method, is obtained.

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Analysis of Gear Wheel-shaft Joint Characterized by Comparable Pitch Diameter and Mounting Diameter

Acta Polytechnica ◽

10.14311/472 ◽

2003 ◽

Vol 43 (5) ◽

Author(s):

J. Ryś ◽

H. Sanecki ◽

A. Trojnacki

Keyword(s):

Carrying Capacity ◽

Small Difference ◽

Design Procedure ◽

Gear Wheel ◽

Combined Loading ◽

Strength Analysis ◽

Load Carrying Capacity ◽

Load Carrying ◽

Load Intensity ◽

New Generation

This paper presents the design procedure for a gear wheel-shaft direct frictional joint. The small difference between the operating pitch diameter of the gear and the mounting diameter of the frictional joint is the key feature of the connection. The contact surface of the frictional joint must be placed outside the bottom land of the gear, and the geometry of the joint is limited to the specific type of solutions.The strength analysis is based on the relation between the torque and statistical load intensity of the gear transmission. Several dimensionless parameters are introduced to simplify the calculations. Stress-strain verifying analysis with respect to combined loading, the condition of appropriate load-carrying capacity of the frictional joint and the fatigue strength of the shaft are applied to obtain the relations between the dimensions of the joint and other parameters. The final engineering solution may then be suggested. The approach is illustrated by a numerical example.The proposed procedure can be useful in design projects for small, high-powered modern reducers and new-generation geared motors, in particular when manufactured in various series of types.

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Influence of Yield Strength Variability over Cross-Section to Steel Beam Load-Carrying Capacity

Nonlinear Analysis Modelling and Control ◽

10.15388/na.2005.10.2.15129 ◽

2005 ◽

Vol 10 (2) ◽

pp. 151-160 ◽

Cited By ~ 3

Author(s):

J. Kala ◽

Z. Kala

Keyword(s):

Yield Strength ◽

Cross Section ◽

Carrying Capacity ◽

Bending Moment ◽

Statistical Characteristics ◽

Load Carrying Capacity ◽

Load Carrying ◽

Strength Variability ◽

Hot Rolled ◽

Hot Rolled Steel

Authors of article analysed influence of variability of yield strength over cross-section of hot rolled steel member to its load-carrying capacity. In calculation models, the yield strength is usually taken as constant. But yield strength of a steel hot-rolled beam is generally a random quantity. Not only the whole beam but also its parts have slightly different material characteristics. According to the results of more accurate measurements, the statistical characteristics of the material taken from various cross-section points (e.g. from a web and a flange) are, however, more or less different. This variation is described by one dimensional random field. The load-carrying capacity of the beam IPE300 under bending moment at its ends with the lateral buckling influence included is analysed, nondimensional slenderness according to EC3 is λ¯ = 0.6. For this relatively low slender beam the influence of the yield strength on the load-carrying capacity is large. Also the influence of all the other imperfections as accurately as possible, the load-carrying capacity was determined by geometrically and materially nonlinear solution of very accurate FEM model by the ANSYS programme.

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Fuzzy Sets Theory in Comparison with Stochastic Methods to Analyse Nonlinear Behaviour of a Steel Member under Compression

Nonlinear Analysis Modelling and Control ◽

10.15388/na.2005.10.1.15135 ◽

2005 ◽

Vol 10 (1) ◽

pp. 65-75 ◽

Cited By ~ 5

Author(s):

Z. Kala

Keyword(s):

Fuzzy Sets ◽

Carrying Capacity ◽

Stochastic Methods ◽

Nonlinear Behaviour ◽

Load Carrying Capacity ◽

Load Carrying ◽

Input Parameters ◽

Stochastic Solution ◽

Fuzzy Solution ◽

Sets Theory

The load-carrying capacity of the member with imperfections under axial compression is analysed in the present paper. The study is divided into two parts: (i) in the first one, the input parameters are considered to be random numbers (with distribution of probability functions obtained from experimental results and/or tolerance standard), while (ii) in the other one, the input parameters are considered to be fuzzy numbers (with membership functions). The load-carrying capacity was calculated by geometrical nonlinear solution of a beam by means of the finite element method. In the case (ii), the membership function was determined by applying the fuzzy sets, whereas in the case (i), the distribution probability function of load-carrying capacity was determined. For (i) stochastic solution, the numerical simulation Monte Carlo method was applied, whereas for (ii) fuzzy solution, the method of the so-called α cuts was applied. The design load-carrying capacity was determined according to the EC3 and EN1990 standards. The results of the fuzzy, stochastic and deterministic analyses are compared in the concluding part of the paper.

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Pavement Damage Due to Conventional and New Generation of Wide-Base Super Single Tires

Tire Science and Technology ◽

10.2346/1.2174344 ◽

2005 ◽

Vol 33 (4) ◽

pp. 210-226 ◽

Cited By ~ 6

Author(s):

I. L. Al-Qadi ◽

M. A. Elseifi ◽

P. J. Yoo ◽

I. Janajreh

Keyword(s):

Carrying Capacity ◽

Material Properties ◽

Three Dimensional ◽

Fe Analysis ◽

Load Carrying Capacity ◽

Inflation Pressure ◽

3D Finite Element ◽

Load Carrying ◽

Pavement Damage ◽

New Generation

Abstract The objective of this study was to quantify pavement damage due to a conventional (385/65R22.5) and a new generation of wide-base (445/50R22.5) tires using three-dimensional (3D) finite element (FE) analysis. The investigated new generation of wide-base tires has wider treads and greater load-carrying capacity than the conventional wide-base tire. In addition, the contact patch is less sensitive to loading and is especially designed to operate at 690kPa inflation pressure at 121km/hr speed for full load of 151kN tandem axle. The developed FE models simulated the tread sizes and applicable contact pressure for each tread and utilized laboratory-measured pavement material properties. In addition, the models were calibrated and properly validated using field-measured stresses and strains. Comparison was established between the two wide-base tire types and the dual-tire assembly. Results indicated that the 445/50R22.5 wide-base tire would cause more fatigue damage, approximately the same rutting damage and less surface-initiated top-down cracking than the conventional dual-tire assembly. On the other hand, the conventional 385/65R22.5 wide-base tire, which was introduced more than two decades ago, caused the most damage.

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