Express Model for Load Sharing and Stress Analysis in Helical Gears

2004 ◽  
Vol 127 (6) ◽  
pp. 1161-1172 ◽  
Author(s):  
Raynald Guilbault ◽  
Claude Gosselin ◽  
Louis Cloutier
Keyword(s):  
Computing Time ◽  
Three Dimensional ◽  
Load Sharing ◽  
Helical Gear ◽  
Design Tool ◽  
Design Stage ◽  
3D Fem ◽  
Early Design Stage ◽  
Stiffness Reduction ◽  
Tooth Base

The performance of a gear set is strongly influenced by the manufacturing and assembly quality. Therefore, detailed analyses at the design stage, where the effects of expected assembly and manufacturing errors can be simulated, are crucial. At an early design stage, when contact conditions are addressed, the widely used finite element method (FEM) may still result in unwanted computing time. The paper presents an Express model developed to serve as a fast design tool offering fine simulation and a high precision level. The model establishes load sharing, fillet stresses and pressure distribution along the contacting surfaces of meshing helical gear teeth. The calculations combine the finite strip method with a pseudo-three-dimensional (3D) model of the tooth base solved with finite differences to calculate tooth bending deflexion and fillet stresses. The accuracy of the procedure is demonstrated through 3D FEM models. A contact cell discretization completes the model. This very fast and accurate approach gives the contact pressure distributions resulting from the roll-slide motion of mating teeth. An analysis of a helical gear set in two different assembly positions reveals the effects of edge contact, and exhibits the influence of tooth stiffness reduction near tooth corners.

Fast approach to calculate the ballastless track impedance

2018 ◽  
Vol 37 (1) ◽  
pp. 176-188
Author(s):  
Hanhua Zhang ◽  
Jun Li ◽  
Jun Zou ◽  
Zhixin Wang ◽  
Jin Yang
Keyword(s):  
Computing Time ◽  
Three Dimensional ◽  
3D Fem ◽  
Decomposition Approach ◽  
Content Type ◽  
Ballastless Track ◽  
Fast Approach ◽  
Fem Method ◽  
Reinforcement Bar ◽  
Partial Element Equivalent Circuit

Purpose The track impedance is one of the most important parameters in designing the track circuit which is widely used in the railway signal control system to detect the presence of a train. This paper aims to calculate the ballastless track impedance by taking account of the influence of reinforcement bars. Design/methodology/approach This paper proposes a two-step decomposition approach to calculate the ballastless track impedance. The basic idea is evaluating the track impedance without the reinforcement bars by using two-dimensional (2D) finite element method (FEM), and the incremental impedance, because of the reinforcement bar, is calculated by the partial element equivalent circuit (PEEC) method. Findings The numerical examples show that the proposed approach can guarantee the accuracy and largely reduce the computing time, at least 20 times, compared with the direct three-dimensional (3D) FEM method. Research limitations/implications The study provides a fast approach to calculate the ballastless track impedance. However, compared with the 3D FEM method, the results are less accurate because of the approximation and assumption adopted in the method. A future study should pay more attention to improve accuracy of the model. Originality/value A fast approach is proposed to calculate the ballastless track impedance taking account of the influence of the reinforcement bars. The computing time can be largely reduced by using the method. With the proposed approach, the influence of insulation of the reinforcement bars on track impedance can be analyzed.

Response Comparisons of a Large Floating Structure by Grillage and Shell FE Models

2008 ◽  
Author(s):  
Kazuhiro Iijima ◽  
Junghyun Kim ◽  
Tetsuya Yao
Keyword(s):  
Stress Responses ◽  
Three Dimensional ◽  
Design Stage ◽  
Design Parameters ◽  
Beam Model ◽  
Floating Structure ◽  
Response Level ◽  
Design Work ◽  
Early Design ◽  
Early Design Stage

At the early design stage of a large floating structure, it is firstly important to know the hydroelastic response characteristics in waves. For this purpose, the structure is modeled by three-dimensional grillage, and hydroelastic analysis is performed in order to estimate the overall behaviour. At this stage, main design parameters are: floater shapes, their arrangement and rigidity distributions. They are optimized by referencing to the hydroelastic responses estimated by the analysis. As the design work develops, more detailed modelling is possible. At the final design stage, the design must be confirmed by checking the response against criteria. The structure is re-modeled by shell FE elements for skin structures and beam elements for stiffeners. It is considered that the more correct estimations are performed by employing the refined model. However, there might be significant differences in the modelling and also in the resultant estimations between the first and final stages even when the subject structure is identical. Then, it is necessary to evaluate the differences between the results estimated by using these two models in order to assure the actual response level estimated by using the beam model at the early design stage. In this paper, three-dimensional grillage and shell FE structural models of a large floating structure are prepared. Hydroelastic analyses are performed on the two models. The results are compared in terms of motion, member force and stress responses.

scholarly journals Efficient Structural Design of a Prefab Concrete Connection by Using Artificial Neural Networks

2020 ◽  
Vol 12 (19) ◽  
pp. 8226
Author(s):  
Jorge Navarro-Rubio ◽  
Paloma Pineda ◽  
Roberto Navarro-Rubio
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Structural Design ◽  
Precast Concrete ◽  
Computing Time ◽  
Plate Thickness ◽  
Economic Benefits ◽  
Design Tool ◽  
Design Stage ◽  
Artificial Neural

In the built environment, one of the main concerns during the design stage is the selection of adequate structural materials and elements. A rational and sensible design of both materials and elements results not only in economic benefits and computing time reduction, but also in minimizing the environmental impact. Nowadays, Artificial Neural Networks (ANNs) are showing their potential as design tools. In this research, ANNs are used in order to foster the implementation of efficient tools to be used during the early stages of structural design. The proposed networks are applied to a dry precast concrete connection, which has been modelled by means of the Finite Element Method (FEM). The parameters are: strength of concrete and screws, diameter of screws, plate thickness, and the posttensioning load. The ANN input data are the parameters and nodal stresses obtained from the FEM models. A multilayer perceptron combined with a backpropagation algorithm is used in the ANN architecture, and a hyperbolic tangent function is applied as an activation function. Comparing the obtained predicted stresses to those of the FEM analyses, the difference is less than 9.16%. Those results validate their use as an efficient structural design tool. The main advantage of the proposed ANNs is that they can be easily and effectively adapted to different connection parameters. In addition, their use could be applied both in precast or cast in situ concrete connection design.

Study of Metamodeling Techniques and Their Applications in Engineering Design

1999 ◽  
Author(s):  
Nanxin Wang ◽  
Ping Ge
Keyword(s):  
Engineering Design ◽  
Computing Time ◽  
Simulation Models ◽  
Surrogate Models ◽  
Design Stage ◽  
Academic Field ◽  
Early Design ◽  
Early Design Stage ◽  
Linear Partial Differential Equations ◽  
Design Alternatives

Abstract Physics based or mechanistic simulation models are frequently used in current engineering design to generate, evaluate and validate designs in order to shorten the design cycle time and reduce the cost. It often involves solving a set of none linear partial differential equations, which usually requires a lot of computing time to search for a solution. It can not satisfy the need to explore more design alternatives in the early design stage. Metamodeling is an active academic field and is attracting increased attention from the industry. Surrogate models built with the metamodeling techniques provide faster analysis alternatives to the mechanistic models. Using these surrogate models in the early design stage allows engineers to explore more design alternatives with less development time and therefore has the potential to enable better engineering decision to produce quality products for reduced cost. In this paper, we review the existing metamodeling techniques including design of experiments, response surface methodologies, machine learning, and kriging. The paper also documents the results of the performance evaluation of several different metamodeling tools using a vehicle greenhouse example.

scholarly journals APIX: Analysis From Pixellated Inputs in Early Design Using a Pen-Based Interface

2011 ◽  
Author(s):  
Sundar Murugappan ◽  
Vinayak ◽  
Karthik Ramani ◽  
Maria C. Yang
Keyword(s):  
Product Development ◽  
Early Stage ◽  
Three Dimensional ◽  
Geometric Constraints ◽  
Design Stage ◽  
Two Dimensional ◽  
Element Analysis ◽  
Early Design ◽  
Early Design Stage ◽  
Simulation Tools

Product development is seeing a paradigm shift in the form of a simulation-driven approach. Recently, companies and designers have started to realize that simulation has the biggest impact when used as a concept verification tool in early stages of design. Early stage simulation tools like ANSYS™ Design Space and SIMULIA™ DesignSight Structure help to overcome the limitations in traditional product development processes where analyses are carried out by a separate group and not the designers. Most of these commercial tools still require well defined solid models as input and do not support freehand sketches, an integral part of the early design stage of product development. To this extent, we present APIX (acronym for Analysis from Pixellated Inputs), a tool for quick analysis of two dimensional mechanical sketches and parts from their static images using a pen-based interface. The input to the system can be offline (paper) sketches and diagrams, which include scanned legacy drawings and freehand sketches. In addition, images of two-dimensional projections of three dimensional mechanical parts can also be input. We have developed an approach to extract a set of boundary contours to represent a pixellated image using known image processing algorithms. The idea is to convert the input images to online sketches and use existing stroke-based recognition techniques for further processing. The converted sketch can now be edited, segmented, recognized, merged, solved for geometric constraints, beautified and used as input for finite element analysis. Finally, we demonstrate the effectiveness of our approach in the early design process with examples.

A simplified daylighting design tool for high-density urban residential buildings

2001 ◽  
Vol 33 (4) ◽  
pp. 259-269 ◽  
Author(s):  
E Ng
Keyword(s):  
Residential Buildings ◽  
Building Blocks ◽  
Design Tool ◽  
High Density ◽  
Design Stage ◽  
Planning Stage ◽  
Early Design ◽  
Early Design Stage ◽  
Geometrical Properties ◽  
Daylight Performance

The paper describes a simple design tool for architects to estimate daylight performance of high-rise residential buildings in high-density urban sites during the early design stage. The tool is based on a modified version of the original split flux formulae. The tool resolves the formulae to a set of tables relating vertical obstruction angles with horizontal obstruction angles. Given the geometrical properties and the required daylight performances, an architect could work out, at the early design and planning stage, the design configuration of the building block itself, the spacing between building blocks, and the sizes of windows required. Working examples demonstrate how the tool might be used in design.

scholarly journals Adaptation of an Early Design Stage Tool for Assessment of Sustainable Energy Systems (SES) in Large UAE Buildings

2015 ◽  
Vol 07 (2) ◽  
Keyword(s):  
Sustainable Energy ◽  
Energy Systems ◽  
Design Tool ◽  
Design Stage ◽  
Design Development ◽  
Building Stock ◽  
Early Design Stage ◽  
Sustainable Energy Systems ◽  
Typical Design

he paper outlines a new design tool for the assessment of sustainable energy systems (SES) for large buildings that is being adapted for the UAE building stock and climate context. The structure and underlying framework is discussed for SES and building types appropriate to the UAE. The mapping of the various levels of input and output of the tool to a typical design development process are described and initial characterization of some components are presented.

Advanced noise modeling for future propulsion systems

2018 ◽  
Vol 17 (6-8) ◽  
pp. 576-599 ◽  
Author(s):  
Stéphane Moreau ◽  
Michel Roger
Keyword(s):  
Three Dimensional ◽  
Broadband Noise ◽  
Design Stage ◽  
Acoustic Analogy ◽  
Propulsion Systems ◽  
Modal Expansion ◽  
Early Design Stage ◽  
Strip Theory ◽  
Noise Models ◽  
Bypass Ratio

In order to meet noise specifications for future foreseen aircraft propulsion systems, such as for ultrahigh bypass ratio turbofans and contra-rotating open rotors, the dominant turbomachinery noise mechanisms need to be modeled accurately at an early design stage. Two novel methods are presented here, which could significantly improve the existing analytical noise models. For the high-solidity ultrahigh bypass ratio, a mode-matching technique based on a modal expansion of acoustic and vortical variables in each subdomain of a blade row is shown to accurately reproduce sound generation and propagation in two-dimensional bifurcated channels and in three-dimensional annular unstaggered flat-plate cascades. For the low solidity contra-rotating open rotors, several extensions to Amiet’s compressible isolated airfoil theory are coupled with Curle’s and Ffowcs Williams and Hawkings’ acoustic analogy in the frequency domain within a strip theory framework, to yield both far-field tonal and broadband noise. Including sweep in both tonal and broadband noise models is shown to significantly improve the comparison with experiments on a stationary swept airfoil in a uniform turbulent stream and on a realistic contra-rotating open rotor geometry at approach conditions.

Derivation of Design Guidelines for Miniature Machine Tools

2004 ◽  
Author(s):  
Nozomu Mishima
Keyword(s):  
Machine Tools ◽  
Metal Cutting ◽  
Evaluation Method ◽  
Design Guidelines ◽  
Design Tool ◽  
Design Stage ◽  
Local Error ◽  
Early Design Stage ◽  
The Difference ◽  
Micro Machine

As has been demonstrated the “microfactory”, which is a miniature manufacturing system proposed by the author and his research group, small machine tools that are comparable in size to their target products lead to large reductions in energy consumption and occupied space. They also increase the flexibility of system reconfiguration because of their low weight and small size. Although it had been thought that micro machine tools might not have sufficient metal cutting capability, experiments showed that were capable of micro mechanical fabrication. However, the design of miniature machine tools has not been fully optimized. For example, the design target of the first prototype, a performable miniature machine (“Micro lathe”), was to make the overall size as small as possible. The author proposed a design evaluation method to roughly estimate machine tool performances during its early design stage. In this paper, the above-mentioned design tool is applied to find suitable miniaturizing strategies. By applying the design tool to the miniaturization of machine tools, it is possible to determine which of the design candidates have the best theoretical performance and which of the local error factors would significantly affect machine performance. From the results of calculation, the tool can clarify the difference of effect of error sources on performances between normal machine tools and miniature machine tools. This leads to some suggestions regarding structures, sizes and suitable machine components. Design guidelines for miniature machine tools can be obtained from the information.

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