BS ISO 22140:2021 pdf download – Passenger cars — Validation of vehicle dynamics simulation — Lateral transient response test methods 6 Simulation tool requirements 6.1 General The simulation tool used to predict behaviour of a vehicle of interest shall include a mathematical model capable of calculating variables of interest (see Clause 5) for the test procedures being simulated. In this document, the mathematical model is used to simulate an open-loop test series as specified in ISO 7401 and provide calculated values of the characteristic variables and functions of interest. The simulation tool shall be able to cover the lateral acceleration level of time domain tests where lateral acceleration value starts from the nominal value of 4,0 m/s 2. The procedure for obtaining input data from experiments may differ for simulation tools, however, the input data shall not be manipulated for better correlation. Nonetheless, adaptation of input data to actual testing conditions such as road friction should be allowed. 6.2 Mass and inertia The mathematical model should include all masses, such as the chassis, engine, payloads, unsprung masses, etc. The value of the mass, the location of the centre of mass, and moments and products of inertia are essential properties of the vehicle for the tests covered in this document. Vehicles with significant torsional frame compliance require a more detailed representation that includes frame-twist effects that occur in extreme manoeuvres. 6.3 Tires The vertical, lateral, and longitudinal forces and aligning and overturning moments where each tire contacts the ground provide the main actions on the vehicle. The fidelity of the prediction of vehicle movement depends on the fidelity of the calculated tire forces and moments. Differences between the tire force and moment measurements used for the model and those used in vehicle testing can be expected due to different wear and aging histories. Although it is difficult to account for these differences, it is important to acknowledge and understand them. Large lateral slip angles and camber angles can occur under the conditions covered in this document. The tire model shall cover the entire range of slip (lateral and longitudinal), inclination angle relative to the ground, and load that occur in the tests being simulated. The tire lateral force reduction at high slip angles is a critical characteristic that shall be comprehended by the tire testing and modelling. The effect of combined tire lateral and longitudinal slip on forces and moments shall...

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