Titanium safety cages in the automotive racing industry Tomaz Bucar, Ph.D.
INTRODUCTION TITANIUM IN AUTO INDUSTRY Increasing demand for more fuel-efficient and environmentally friendly road vehicles. Weight reduction leads to fuel savings of a vehicle. 1% reduction in mass can result in 0.7% reduction in fuel consumption. In addition to weight savings, the visual appearance as well as performance with titanium attracts customers.
INTRODUCTION TITANIUM IN AUTO INDUSTRY Several automotive components can be replaced with titanium: engine valves valve springs and retainers connecting rods suspension springs exhaust systems turbocharger compressor wheels various fasteners. The application of titanium and its alloys to automotive components has grown in the last years.
INTRODUCTION TITANIUM IN AUTO INDUSTRY High price of titanium has prevented realization of all these applications in mass-produced passengers cars. A lot of applications were realized in racing cars where weight reduction is critical. Titanium has a long record of success in performance and racing cars (beginning of the 1980s).
INTRODUCTION AUTOMOTIVE RACING INDUSTRY Designers are constantly trying to save a few extra grams of weight in their design. Material choice plays a large part in the design equation. Safety cages represent an attractive entry point for titanium into the automotive racing industry.
INTRODUCTION SAFETY CAGES Multi-tubular structure installed in the cockpit and fitted close to the bodyshell of a wehicle: they help to stiffen the chassis reduce the deformation of the bodyshell (chassis) in case of an impact used in purpose-built race cars and cars modified for racing many different roll cage designs depending on the application different racing organizations have different specifications and regulations.
INTRODUCTION SAFETY CAGES Minimum configuration of a safety cage is defined according to the regulations: MAIN ROLLBAR FRONT ROLLBAR REINFORCEMENTS DOORBARS Weight of standard steel safety cage is more than 50kg!
TITANIUM SAFETY CAGES DEVELOPMENT TITANIUM SAFETY CAGES With direct substitution of steel cage with titanium an immediate weight reduction of 40% can be achieved. But safety cages are actually STIFFNESS CONSTRAINED! Successful application of titanium alloys for safety cages demands a thorough consideration of titanium's unique properties. Low modulus of titanium requires components redesign in this stiffness limited application.
TITANIUM SAFETY CAGES DEVELOPMENT DEVELOPMENT PROCEDURES The development starts with the safety cage design made by the help of CAD. ORIGINAL STEEL SAFETY CAGE REDESIGNED TITANIUM SAFETY CAGE Original steel safety cage was redesigned considering titanium unique properties.
TITANIUM SAFETY CAGES DEVELOPMENT DEVELOPMENT PROCEDURES The CAD model of the safety cage is the core element for all subsequent numerical analyses and test methods. FE MODEL Next step is 3D CAD model discretization. Attention to details discretization.
TITANIUM SAFETY CAGES DEVELOPMENT DEVELOPMENT PROCEDURES The complete safety cage must be subjected to the static load tests in accordance with the regulations: F Vertical load of F = 75 (w+150) [N], where w [kg] is weight of the car. Applied on the top of the main rollbar. RIGID CONSTRAIN Mounting points are rigidly constrained.
TITANIUM SAFETY CAGES DEVELOPMENT DEVELOPMENT PROCEDURES Finishing the CAD model discretization phase, structural numerical analyses based on the FEM follow. DEFORMATION STRESS
TITANIUM SAFETY CAGES DEVELOPMENT DEVELOPMENT PROCEDURES Finally the first prototype was made in accordance with the approved CAD model. TESTING DEVICE Measurements are carried out on the standardized testing device in order to prove corelation: FEM TESTING
CONCLUSION SUMMARY Using titanium in safety cages means weight reduction better results both in the vehicle performance and fuel efficiency. Weight reduction of the Porsche GT3 titanium safety cage compare to steel one is 35% (from 41 to 26.5kg) Weight is reduced in the upper part of the vehicle.