The automotive trade continues its efforts to cut back automobile gas consumption and emissions. The simplest technique to obtain each objectives is to lower automobile weight. A 25% discount in automobile weight lessens gas consumption by round 10%, whereas a 25% lower in aerodynamic drag yields solely a couple of 5% discount.
Early efforts at chopping weight centered on the biggest and heaviest assemblies, akin to altering from forged iron to aluminium engine blocks. With such massive weight reductions already achieved, vehicle authentic tools producers (OEMs) and suppliers now give attention to squeezing each final pointless ounce out of smaller components.
KSR International engineers used Ansys topology optimisation to largely automate the method of redesigning a brake pedal. In comparison with standard design strategies, digital exploration utilizing topology optimisation decreased structural optimisation time from seven to 2 days and achieved a 21% weight saving – significantly greater than may have been achieved utilizing standard strategies.
Position of the brake pedal
KSR Worldwide is an trade chief within the design, engineering and manufacture of quite a few automotive sensors, together with accelerator pedal modules, digital throttle management sensors, adjustable and glued pedals, electrical steering management models and energy modules for vehicles, gentle vehicles and all-terrain automobiles (ATVs).
The corporate makes greater than 14 million fastened brake and clutch pedal modules a yr.
The brake pedal is the first driver interplay level with the braking system and should switch all regular and irregular loading that may happen in panic conditions whereas remaining absolutely purposeful.
On this mission, the brake pedal that was optimised is designed to resist a pushing drive exerted by the driving force of greater than 2,000 Newtons and vital lateral and reverse masses.
Finite ingredient evaluation with Ansys Mechanical confirmed low stresses in lots of areas of the pedal beneath all 4 load instances, which indicated the potential for weight elimination.
The standard strategy to cut back the load of the pedal was to develop new designs for simulation, both separately by manually defining their geometry, or dozens at a time by parametrically various their dimensions.
Utilizing this strategy, it might take an engineer about one and a half weeks to attain substantial weight financial savings by lowering materials in low-stress areas, rerunning the simulation, then modifying the design based mostly on the simulation outcomes. For this utility, standard strategies would have been prone to obtain vital weight financial savings, however the ultimate design wouldn’t be absolutely optimised from a weight standpoint.
Redesigning the half
The Ansys topology optimiser goes past incremental adjustments, akin to adjusting the dimensions or thickness of particular person options, by basically beginning with a clean sheet of paper and designing the half from the start to fulfill aims specified by the engineering group.
The topology optimiser is built-in with Ansys Mechanical inside Ansys Workbench. KSR engineers outlined the options to be maintained within the ultimate design because the outer boundaries and mounting surfaces (the place the pedal is connected to different components) of the preliminary design.
They arrange the simulation in order that thickness all through the half was the identical because the earlier design, a requirement to fulfill manufacturability constraints of the stamping operation used to provide the pedal. They then outlined the optimisation goal as minimising the half’s weight whereas holding stress to a specified most worth based mostly on the fabric properties.
The Ansys topology optimiser outlined a geometry for all 4 load instances that met the design necessities on the lowest potential weight. KSR engineers carried out one other structural evaluation of the brand new design and decided that stresses had been at acceptable ranges all through the half.
Additionally they noticed that stresses had been very low alongside one edge, indicating the potential for extra weight financial savings.
As a result of these low stresses had been attributable to sustaining all the outer boundary within the ultimate half, they achieved extra weight financial savings by eradicating this boundary.
Saving weight and time
The optimised design weighs 694 grams, a discount of 192 grams from the 886-gram authentic design. The brand new design could be applied at no extra value as a result of a brand new stamping die have to be constructed each time a pedal is designed for a brand new mannequin automobile.
These enhancements had been achieved in just one and half days, far much less time than would have been required to optimise the design utilizing conventional strategies. It needs to be famous that this determine refers back to the time required to fulfill structural necessities for a particular configuration of a pedal.
Further time is required to package deal a pedal for a particular automobile configuration. The load financial savings that had been achieved through the use of topology optimisation had been a lot better than people who may very well be achieved by altering design parameters with both guide or automated optimisation.
The automotive OEM that buys the brake pedals from KSR could be very happy with the load financial savings. KSR plans to make use of topology optimisation sooner or later to attain substantial weight financial savings with out having to speculate vital engineering sources.