EMS5CAE – Computer Aided Engineering ANSYS (2019)

Individual Assignment

Manufacturing Engineering

Due Date: Monday, 16 May 2019

Analysis of an RC Automotive Suspension Setup

1 Outline Automotive components can be exposed to multiple loading conditions as well as

having to operate in – and withstand harsh environments. With the increases in competition between various organisations, there is an ever-growing pressure to deliver changes in design requirements within small time frames. However, the nature of this competitive environment also requires designs to withstand expected conditions and meet minimum service life requirements, therefore placing high demand on engineering teams to apply computer aided engineering tools to analyse the effects of different conditions and designs before constructing physical prototypes for experimental testing.

Double wishbone suspension systems are common automotive components, even used on smaller scale RC models. Not only does a double wishbone suspension system consist of multiple parts, but also a range of connection types and damping mechanisms.

Many factors need to be considered when designing components with such these complex assemblies. These include; cost, design life, loads, deflections, dynamic behaviour, material etc. – all of which have to be analysed to ensure the safety and reliability of the assembly.

For the RC suspension system considered in this task, the main boundary conditions consist of:

▪ Directional forces caused from steering ▪ Moments that are the result of loading and support conditions ▪ The effect of spring stiffness on the system ▪ The effect of different joint conditions

2 Objectives The aim of this project is to conduct a finite element based structural, modal and harmonic response analysis of an RC double wishbone suspension system. The system and

each component in the assembly must be scoped and investigated for the given boundary conditions and spring stiffness.

You will need to perform a mesh convergence study and show a plot of element size (side length) vs max principle stress in the region of interest.

Each student is assigned a length for the front lower arm and spring stiffness that you are to use, meaning each student must adjust the geometry and model accordingly, Figure 1.

Then, you are to assign appropriate materials to the given model. The initial study must use structural steel for each component. Then, apply a different material for the rim and for the wishbones (such as ABS, PLA, Nylon, aluminium alloy etc.). Each wishbone arm must have the same material.

For the modal, harmonic response and structural analysis, you are to consider –

▪ The vibrational frequency of members at different mode shapes with application of Standard Earth Gravity. (No Frequency is Zero Hz)

with the first cut.geometries to align Then modify these

at this location.per your individual value Adjust the geometry as

1Figure

▪ Assigning appropriate materials for the rim and wishbone arms. ▪ What and where are the maximum stresses due to the given loading conditions. ▪ Where are the maximum stresses and is the solution independent of the mesh

(conduct a mesh study). ▪ The range of operating frequencies that the structure will experience is up to

~50Hz. Is it likely there will be a problematic frequency for this force input within the given range of frequencies?

▪ Conduct a harmonic analysis to understand the change in stresses and deformations at the given problematic frequency.

▪ The boundary conditions (loads and supports) that are modelled must provide accurate representation for the following loading cases;

1. Force defined by components on the outer mid surface of the rim. 2. Moment on the 2 outer surfaces of the rim. 3. Remote displacement simulating a fixed location where a steering arm

would be connected. 4. Spring fastened to the lower wishbone arm with the opposite end fastened

at a given offset location. 5. Representation of the spherical and pin-type joints connecting the

suspension assembly to the rim and vehicle.

During post processing you must analyse the stress and deformation contours of the suspension, comment on the stress development within the assembly.

Based on the results of initial analysis modify the material of both wishbones and evaluate the effect on the stress and deformation. Are you able to change material and reduce the overall weight of the system while all the supports and boundary conditions remain the same?

Having done the analysis and looked at the effect of the different materials and mesh, write a technical report of the design process.

3 Loading Conditions

arm assem lowerFront

Front upper arm assem

Front Hub Carrier R assem

connections. oints and Part names, j

N20-Z Component: Y Component: 5 N

X Component: 0N Face of force component:

Force component

N.mm0Z Component: N.mm0Y Component:

.mmN 050X Component: of Moment component: esFace

Moment

All others: Free Z Component: 0 mm

displacement:Face of remote

Remote displacement.

4 Technical Report Layout

The report can be laid out as follows:

• Use size 12 font for the body text, and format section and titles accordingly. • Font can be Timed New Roman, Calibri or similar. • Use spell check and read your assignment before submitting. • Reference figures and other sources of information. Use a referencing tool such as

Zotero https://www.zotero.org/ • Use the numeric IEEE style type.

• MAX 2000 words! Be concise!

To ensure your submission fits the page/word count ranges, make certain to count words in the body using your word processor and then add in the equivalent word counts for your tables and images. References do not count towards the wordcount. Figures and tables are counted by the amount of words they replace. A good rule of thumb is 50 words per image (picture, graph, spectrum, etc.). Figures with two images (e.g. 1A and 1B) are counted as 100 words. Three images amount to 150 words and so on. Brief tables are counted as 100 words each, while longer or wider tables can be up to one full page (200 words). Make sure you include only highly relevant images and remove non-essential images to help your manuscript be more reader-friendly while fitting within the page/word limits.

A Technical Report can contain the following sections: Section Details Title page Title of the report. Student details including name, ID, date and subject, the

main text word count. Summary A summary of the whole report including important features, results and

conclusions Contents Numbers and lists all section and subsection headings with page numbers

Introduction States the objectives of the report and comments on the way the topic of the report is to be treated. Leads straight into the report itself. Must not be a copy of the introduction in this handout.

The sections which make up the body of the report

Divided into numbered and headed sections. These sections separate the different main ideas in a logical order

Conclusions A short, logical summing up of the theme(s) developed in the main text References Details of published sources using the IEEE style. Acknowledgements List of people who helped you research or prepare the report, including your

proof-readers Appendices (if appropriate)

Any further material which is essential for full understanding of your report (e.g. large-scale diagrams, computer code, raw data, specifications) but not required by a casual reader

Systéme International (SI) units are to be used. Non-SI measurements can be

included, but they should follow the SI measurement in parentheses. An example is 2.54 cm (1.00 inch).

NOTE: For each there are different dimensions given. The measurements given to me are mentioned below;

{Length(mm): 0.65; Stiffness(N/mm): 14.3}