RACE (Rapid Axle Concept Evolution) is a cloud based multibody simulation (MBS) / multibody dynamics (MBD) software for the development of suspension systems.
At RACE Software we believe the value add in any simulation and analysis activity comes from the time spent analysing results and deciding on the next design iteration. Time spent on model build, debug, parameterisation, post-processing, etc. does not improve your design, it is essential non-value add. RACE has been developed to minimise the time spent on these non-value add activities during the development of automotive and motorsport suspension systems.
RACE requires user inputs in the form of suspension hardpoints, joint types and wheel and tyre dimensions. Once complete the user submits the inputs to a dedicated cloud server for analysis. The server runs Kinematics and Compliance (K&C) simulations in which vertical, roll, cornering, steering, aligning torque, traction and braking loads are applied to the suspension system and the response of the system to each is recorded. Once complete RACE generates reports ( Pdf and raw CSV) to show the performance of the suspension against over 50 Key performance indicators (KPIs). The reports are then uploaded to the users account for review.
RACE Software currently has two different levels to cater for different use cases and user needs.
Both RACE Standard and Advanced level accounts come with preloaded demo simulations for all suspension types for the user to import them quickly and make changes to their desired design, for ease of use.
To get a glimpse of the RACE Software reports download here a PDF Demo STANDARD Report – Double Wishbone Suspension and here a PDF Demo ADVANCED Report – Double Wishbone Suspension. Besides the PDF Reports users will get raw CSV data outputs for further analysis and results interpretation for KPIs, KnC outputs and nonlinear bushes / joins (Advanced only).
This guide walks the user through the different sections of the input template which the user must complete to run an analysis in RACE. The first step is navigate to the ‘Run a simulation’ page on the RACE platform and select the suspension type you would like to simulate. This opens a new simulation template for your chosen suspension type.
At the bottom of the page you shall find quick explainer videos of both RACE Software Standard and Advanced levels.
Inputs can be loaded from a previously run simulation or suspension hardpoints can be loaded from a csv file. To load from a previously run simulation, click ‘load from a previous simulation’. This brings you to the previous simulations page. Find the simulation you would like to load and click ‘Load’. This populates a new simulation with a copy of the previous simulation inputs.
To load a csv file containing suspension hardpoints, first choose the file you want to load by clicking the ‘choose file’ button. Then click ‘Load hardpoints from the selected csv file’. If the load is successful, you will get a message saying ‘Success: csv file uploaded and hardpoint input fields updated’.
The CSV file should have one hardpoint per line in the format: hardpoint, x-coordinate, y-coordinate, z-coordinate. The csv example below loads three hardpoints for P3, P4 and P6:
3, 50, -400, 305
4, 100, -400, 300
6, 100, -700, 280
The hardpoints must be entered in the RACE Software coordinate system. The X-axis points towards the rear of the vehicle, the Y-axis points to the right of the vehicle and the Z-axis points upwards. The vehicle centre line is at Y = 0. The axis system is shown below:
Figure 1. RACE Software Vehicle X,Y,Z Coordinate System
Each suspension template uses a suspension hardpoint numbering convention to simplify the naming of the different hardpoints in the system. The hardpoint numbering convention is defined for each suspension type in the user input template as shown in the example below for a double wishbone suspension.
Figure 2. RACE Software Standard – Double Wishbone Suspension Hardpoint Numbering
In RACE Standard the joint types can be defined by selecting the appropriate stiffness for each joint in the suspension using the drop down boxes. The joint rate (or stiffness) terminology used in RACE is shown are in the diagram below.
Figure 3. RACE Software – Bush/Joint Diagram – Radial, Axial, Conical, Torsional Stiffness Directions
RACE Standard has a pre-populated set of joint options, these include standard bushes, compliance bushes, ball bushes and ball joints.
Some joints in the suspension has specialised options. These include:
In RACE Advanced nonlinear joint rates can be specified at key positions in the suspension. The nonlinear joints allow user defined radial, axial, conical and torsional rates, with the option to specify nonlinear rates in the radial and axial directions. The following inputs are required to define the nonlinearity of the joint:
The values above define three points on the nonlinear curve of the joint. RACE calculates a combined linear and cubic stiffness curve for the joint which passes through the three points. If the nonlinear parameters are not realistic (e.g. linear travel greater than total travel), the joint defaults to a linear joint.
Figure 4. RACE Software Advanced – Non-linear Bush/Joint Definition Example
Each suspension type has a topology section where the user can customise the layout of their suspension. The topology section allows the user to select the part that dampers, springs and anti-roll bar drop links are attached to. For example, on a Double wishbone suspension the damper can be attached to the knuckle, lower control arm or upper control arm. The topology is selected using drop down boxes.
When selecting the topology, the relevant hardpoints must be realistic for the chosen attachment. For example, if the spring is specified as a coilover spring (spring sits over and is attached to the damper), the spring hardpoints must be on or close to the damper axis. Failure to have an aligned set of suspension hardpoints and suspension topology may cause some or all of the RACE simulations to fail.
The tuning and test parameters section is used to define the tuning parts and test parameters for the suspension. Some or all of the following options are available depending on suspension type and RACE subscription level:
Figure 5. RACE Software Advanced – Anti-roll Bar Diagram
Static toe and static camber can be adjusted in RACE by defining the wheel rotation axis direction. The wheel rotation axis is defined by two hardpoints, P9 (wheel centre) and a second hardpoint outboard of wheel centre (P20). The wheel rotation axis is along a line joining P9 and P20. For a given P20 y coordinate, static toe is controlled by the x coordinate of P20 and static camber is controlled by the z coordinate of P20. The wheel rotation axis definition is shown below.
Figure 6. RACE Software Advanced – Camber Adjustment
When populating the input template, RACE runs validation checks on the data entered. If there is a potential issue with the data, RACE will generate an error or a warning when the user clicks ‘Submit and run simulation’.
As with any simulation and analysis activity, failed simulations are a possibility in RACE. The validation checks aim to minimise the chances of this happening but a suspension which passes all validation checks can still fail one or more of the kinematics and compliance simulations (RACE Standard runs 6 kinematics and compliance test events, RACE Advanced runs 7). For example, if you specify a suspension with a very short steering arm on the knuckle, the steering test event will fail because the steering geometry will be infeasible and not able to reach the full rack travel. If less than 3 of the kinematics and compliance test events fail, a key performance indicator report will still be generated but without the results from the failed tests. If more than 3 test events fail an error report is generated showing the simulation inputs to help the user debug the issue.