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Pro / MECHANICAL motorcycle frame design experience

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Motorcycle motorcycle frame is the main bearing components, the strength and fatigue life is critical to the motorcycle, the traditional design method, the general structure and function is to carry out the design, prototype trial again, and then proceed to a prototype of the static strength test, modal test and dynamic response tests, examinations of the static and dynamic characteristics of the frame, if we can not meet the design requirements, need to re-design, & development of prototypes and testing, so on, the process cycle length, spend a lot of manpower, material and financial resources. Can not meet the current requirements of an increasingly competitive market. With the development of computer technology, finite element analysis techniques applied gradually to the design process.

Mechanicall as Pro / ENGINEER main analysis module, set movement, structure, thermodynamics in one, can be static, dynamic, fatigue, impact analysis and so on. Based on Pro / ENGINEER features of a single database, Mechanicall to avoid the traditional analysis of three-dimensional modeling software and the interface between the software problems, they can at any time at any stage in the design to facilitate the completion of the analysis, integration Mechanicall addition to the direct call mode modeling parameters to optimize the analysis, this is the other analysis software can not do.

In this paper, finite element technology, the use of Pro / ENGINEER mechanical model of the establishment of a motorcycle frame to carry out static analysis on the entire analytical process, as well as the End of the post-processing calculation process, in accordance with the principles of mechanics of materials, from the results of the analysis of car aircraft to evaluate the structural strength, the static characteristics of test frame and the frame of the safety check.

Chapter 1 frame structure and frame work load

1.1 Frame structure of motorcycle

The majority of motorcycle frame complex pipe, plate welding structure, is the support of motorcycle frames,

Frame should have sufficient strength, it should bear the engine, other parts and the weight of the crew. Different object frame is not the same as strength.

The stiffness of the frame should be sufficient. Refers to the so-called stiffness on the ability to resist deformation, compared with the four-wheeled vehicles, two motorcycles with a wider range of degrees of freedom of movement. Low stiffness of the frame, when the vehicle frame by shock deformation easy; but the frame just to some extent, the impact of the General Assembly through the system flexibility, thus affecting the crew's comfort.

The structure of the frame size to meet the requirement. Some parts of the frame is critical, affecting the smooth running of a motorcycle. Riser such as the former involves fork angle, drag from the wheels, offset distance, the two moments, such as wheel size problem. Front fork angle, and steering the direction of the handle at the point of view of the mobile will be small; drag from the large, front-wheel rotation the greater the torque, the car will feel more stable. However, the greater the drag shift away from the more heavy-handed, so the general light motorcycle drag from 85 millimeters in -120 mm.

Motorcycle in traffic generated by the shift in power, the centrifugal force and the car bumps along the way, will make appearance before the riser twist, such as resistance to lateral torsion, regular use of large frame beam and the strengthening of the control rod from the engine on both sides of extended to cover pre-stretch position welding riser.

At present, the form of a motorcycle frame is divided into three categories: the main beam structure Frame, Link-type form of the frame and the frame bracket.

Frame structure of the main beam, also known as spine type frame, with one or two main beam of the frame so the spine, this multi-application scooter frame.

Ling the shape of the diamond-shaped pattern of the frame, the frame, also known as diamond-type frame, which belongs to the space frame structure, in the diamond-shaped transverse engine as a supporting frame, the frame to enhance the intensity and rigidity, the application of more motorcycle road race.

The shape of the cradle-type frame brackets, also known as the cradle-type frame is also a form of spatial structure, the engine installed in the cradle-shaped, because of engine bearing pipe below the engine will be able to take the protective effect, so many off-road vehicles using this type of frame.

Discussed in this paper belong to the chassis frame forms the structure of turbot, and its structure as follows:

Pro / MECHANICAL motorcycle frame design experience

Figure 1.1 Frame structure

1.2 frame work load

By the motorcycle can be aware of normal working conditions, the frame in the normal working conditions, re-download two 75Kg in accordance with the standard of the quality of people, that is to say, 150Kg mass distribution in the frame of the cushion rail Department does not consider the set goods, other load on the vehicle chassis for the load, load on the beam pipe in the Department of the fuel tank and fuel quality 10Kg, hanging in the engine of the vehicle chassis weight 10Kg.

Table 1.1 Motorcycle overall load parameters

Parts Parameters
Members of the quality of driving 75Kg 2 people
Engine quality 10Kg
Fuel quality 10Kg

Frame work load as shown:

Pro / MECHANICAL motorcycle frame design experience

Figure 1.2 Figure load frame

As icons, the frame, fork angle of 26 degrees, the crew weight cloth in the seat rail, fuel weight cloth in the upper beam pipe, the engine center of gravity in the post-installation point left fork (186.5,43) Department.

Frame structure of Chapter 2 Static Analysis 2.1 Static analysis of frame structures to deal with the corresponding

Analysis of frame structures include the following main aspects:

2.1.1 Mesh division

Pro / MECHANICALL the use of P-method adaptive technology, and the traditional finite element software, the use of non-H-method adaptive technology. Technology in the P-method, each finite element of the displacement unit are higher polynomial equation (three or more times); in the H-method technique, each element of the finite element displacement equation is a linear equation, quadratic or up to three times Formula One Formula One. H-method non-adaptive technology and adaptive technology in the P-method mesh when the difference between Figure 2.1 and shown in Figure 2.2, it is easy to see that the H-method non-adaptive technology to draw the finite element mesh unit smaller number of more, but with the physical borders of a bad fit; adaptive technology to draw P-method finite element mesh of the larger units, the relatively small number of entities, but with better boundary fitting.

Pro / MECHANICAL motorcycle frame design experience

Figure 2.1 Figure 2.2

Frame is a symmetrical structure, mainly by the thin-walled tube plates and shell composition, which, before the riser, the next possession, the former to strengthen the pipe, the beam tube, seat rail, after the pipe, luggage rack and at the end of tube is thin-walled tube, the former to strengthen the board, after the shock absorber is installed ear pieces of shell plate, part of the seat frame rail as the main bearing components. Analysis of previous methods, the use of beam elements or shell equivalent unit to simplify the model, the equivalent result to simplify the calculation, or the results of poor accuracy. In the computer configuration to allow the case to the frame of the analysis model is not simplified, direct the use of automatic mesh generation method for automatically setting the grid will be set to solid unit tetra (tetrahedral) units.

2.1.2 processing engine

General motorcycle engine connected with the rigid frame, the engine itself is a lot of rigid parts, the actual installation of the engine in the first half of the frame stiffness and strength have improved greatly the role of the analysis frame , we must consider the impact of the engine. In this analysis to simplify the engine into a quality unit (mass), a mass of 10Kg, is located in the engine center of gravity location, connect it with the frame with elastic modulus higher than 1,000 times the normal material of the rigid beam element without quality (Beam) to to deal with.

2.1.3 deal with the shock absorber

Before and after the shock through the frame, fork and wheels after the flat surface on the support in order to improve the accuracy of frame analysis models need to consider before and after the shock, fork and wheels after the level of elastic deformation. After the ping because the stiffness of the wheel fork and a greater approximation to deal with as a rigid, impact on the calculation accuracy. The establishment of the elastic modulus higher than 1,000 times the normal material of the rigid beam element without quality (Beam) after analog-ping fork, and rear-wheel axis Department fully bound by the degree of freedom in the post-shock and post-installation ears flat spring between the fork After the shock absorber unit simulation. The first riser and the axis between the front spring element simulation of pre-shock absorbers, front wheel axis of Office will be fully bound by the degree of freedom, in the former legislation governing the establishment of upper and lower end-bound, retaining only along the axial direction before the riser of the translational freedom , the static load frame to simulate the actual binding conditions.

2.2 Static Analysis Frame Frame Model 2.2.1

The model exists in a number of non-bearing items, such as the installation of external ear, such as plastic parts, in the analysis of the loading process, the frame strength and stiffness have little effect, but because of the complexity of its structure, the grid division, as well as the subsequent process of solving a large number of computers are a waste of resources, thus the need for these non-bearing parts can be simplified, a good model to simplify the following as shown in Figure 2.3

Pro / MECHANICAL motorcycle frame design experience

Figure 2.3 Analysis Model

MECHANICALL mode in accordance with the spatial location as shown in Figure 1.2 the corresponding spring element and beam element.

2.2.2 the allocation of material

MECHANICALL mode in the model simulation, the model needs to specify a range of physical properties, such as density, stiffness and so on. The analysis of most of the frame structure of thin-walled tube plates and shell composition, the material Q235A, its yield limit for 235Mpa, Poisson's ratio 0.3, Young's modulus 200GPa, editing the material properties of steel for car plane distribution of material. Used to simulate the engine, after the fork of the Beam unit level, a new editor of its material properties material to the elastic modulus of 1,000 times for steel, its density of 1 ‰, in order to approximate the quality of simulation of non-rigid unit.

2.2.3 Constraints and loads

2.1.3 simplified shock absorber in the mentioned axisin the frame (that is, before the shock absorption under the endpoint, the endpoint after the fork after the ping) to the establishment of full-bound in the former legislation governing the establishment of upper and lower end-bound, retaining only along the axial direction before the riser of the translational degrees of freedom to simulate the actual working condition frame. Bound by the above processing, there is no rigid body displacement of the frame, there is no singular stiffness matrix.

Pro / MECHANICAL motorcycle frame design experience

Figure 2.4 Frame Model

This analysis, in static load conditions the load parameters in Table 1.1.

Do a good job in the corresponding equivalent, load and other constraints and the model treated above chassis as shown in Figure 2.4.

2.2.4 Analysis

The establishment of a new static analysis and run the analysis after the completion of the calculation can be the result viewer to view the calculated results. Frequently used view showing the deformation results showing equivalent stress (Von Mises) and so on.

Pro / MECHANICAL motorcycle frame design experience

Figure 2.5 Distribution of stress intensity image (Von Mises)

These are the results of the above program, the stress intensity distribution of cloud above 2.5 as shown in Fig.

The results from the above can be, carrying two crew members of the static load conditions, the frame rail and the seat cushion support tube connected to the local stress of the largest maximum 70MPa.

By the mechanics of materials, we can see that the plastic material, the allowable stress [σ], which, for the material yield limit, for the purposes of this case, check 235MPa, n for the material safety factor, in the case of static load , n = 1.2 ~ 2.5. The resulting effect of the static load, when the safety factor to obtain small, high-quality carbon structural steel hot-rolled steel sheet for the static allowable stress [] = 195.8MPa, when the safety factor to obtain large, high-quality carbon steel heat rolled steel sheet of the static allowable stress [] = 94MPa. Resulting in the frame under static load is relatively safe, a safety factor of the larger, is very abundant. The possibility of damage to the frame is relatively small.

2.3 Summary of this chapter

This chapter describes in detail the analysis of motorcycle frame, the model, the division of the grid, the boundary constraint conditions, as well as the frame based on the results of the analysis carried out on the frame of static mechanical analysis, and vehicle The strength of the frame check, come to the conclusion of the safety factor of the frame is relatively high, the possibility of damage to the frame is relatively small.

Chapter 3 Conclusions

In this paper, finite element techniques, the use of three-dimensional modeling tools and PRO-E analysis module Pro / MECHANICAL model of a motorcycle frame structure of the static analysis, and its static load safety discussed . Prior to this, I have used ANSYS for analysis of the frame, ANSYS has a relatively independent of pre-and post-processing module, to complete the analysis of many fields, but the pre-treatment ANSYS, as a result, unable to complete the modeling of complex parts, with other the use of CAD software. Because the model structure is too complex to model using the intermediate format into the ANSYS model after the fracture, the loss of such entities, a direct impact on the follow-up analysis of the model. Adoption of the Pro / MECHANICAL static analysis has been the experience of the following conclusions:

1 Pro / MECHANICAL as Pro / E analysis of the main module, set movement, structure, thermodynamics in one, can be static, dynamic, fatigue, impact analysis, etc., in the operation style is similar to other commonly used module for Pro / E users is very easy to use, has carried on a very good Pro / E to learn to use powerful features. With the traditional analysis software (such as ANSYS, etc.) is highly dependent on the comparison of trained experts, Pro / MECHANICAL ordinary design engineers familiar with the design in their own environment, we can design products to facilitate the study of mechanical properties.

2 directly in Pro / E model to operate, Pro / MECHANICAL eliminates the problem of data transfer, so that engineers can be more convenient at any time in the design process to assess, understand and optimize their designs. Design changes to make it easier and lower cost.

3 Pro / MECHANICAL simulation using the relevant features, design changes, the definition does not require re-analysis of design changes can be evaluated, thus greatly reducing the workload.

Due to space limitations, this article from the static analysis of the Pro / MECHANICAL had experience, the dynamic, fatigue, impact analysis and other functions and optimization of its parameters, and many other advantages in the design process of the application will prompt improve efficiency, reduce product design cycle, which greatly improved the competitiveness of products in the market.

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