STEEL TACKLES WORLD’S TOUGHEST AUTO SAFETY STANDARDS
18 January 2000 - Corus Automotive

Anticipating that motorists, consumer groups, legislators and carmakers will in future place even more emphasis on vehicle safety, the Advanced Vehicle Concepts (AVC) programme by a consortium of leading steelmakers has challenged itself to meet the world’s toughest safety standards anticipated by the consortium for the year 2004 – without compromising the significant 25 to 36 per cent weight saving demonstrated by the first UltraLight Steel Auto Body (ULSAB) project.

Commenting during the first official briefing since the $10m (£6m) programme announcement, Frank Walker said:

'Our initial challenge is to make the popular midsize family car as safe as larger cars. We will demonstrate that at present it is only advanced steels that can cost-effectively address the conflicting demand for lower weight - and thus lower fuel consumption - whilst enhancing safety, performance and retaining comfort levels for mass production vehicles.

'It has become a major technological challenge to make cars not only strong and safe, but also as lightweight and affordable as possible. Despite carmakers’ best efforts to reduce vehicle kerb weights, the fact is they continue to increase as more equipment is introduced as standard – even for the smallest cars.

'Raising the safety standard has the potential to exacerbate this trend, at a time when there is just as much pressure to reduce fuel consumption, CO2 emissions and manufacturing costs. Our goal is to be in front of the curve and we are confident that we can help to reverse the increasing kerb weight trend by using advanced steel technologies to push back even further the boundaries of new car design.'

Main problem is ever-increasing kerb weights … solution is to increase the uptake of ULSAB technologies

The main problem is that European cars have got 20 per cent heavier over the last 20 years. Without applying even more intensively groundbreaking measures such as high strength steels and laser-welded tailored blanks to meet the safety challenge, the motor industry stands to lose half the weight savings already demonstrated through the original ULSAB project simply because of these increasing kerb weights.

The need to counter this trend has resulted in carmakers introducing in their latest models some of the advanced steel technologies revealed by ULSAB, but not yet to the level of application that the original ULSAB body structure was able to demonstrate. Given steel’s predominance as the benchmark material for high volume production, Corus is committed to working in partnership with its automotive customers actively to accelerate the introduction of these fundamental ULSAB technologies.

Corus also has programmes in place to introduce the other main ULSAB technologies comprising tube and sheet hydroforming and laser welding for assembly and aims to be equally pro-active at introducing additional innovations that may arise from the AVC project - such as hydro-mechanical forming and an even higher proportion of ultra-high strength steels.

Main goal is to pursue advanced steel solutions that will meet anticipated year 2004 safety standards

The principal goal of the AVC programme is to pursue sophisticated and highly developed steel solutions for use in vehicles that will meet anticipated year 2004 safety standards. Whereas the original ULSAB programme only considered steels that are currently available, the AVC programme will anticipate what will be technically feasible in the year 2004.

The project will focus on smaller C-class vehicles, which represent the largest market sector accounting for around a third of Europe’s 18.6 million annual car sales.

Alongside design concepts compatible for a midsize C-class vehicle (overall length 4.1 metres, width 1.75 metres) the AVC programme will simultaneously use a common platform strategy to develop a larger PNGV-class vehicle (length 4.75 metres, width 1.82 metres), using the same front-end structure and possibly a common rear end structure with a stretched mid-floor section. Despite its objective of meeting the toughest crash safety standards yet devised, suggesting the need to increase structural mass, the PNGV target weight for the main body structure will in fact remain consistent with the original ULSAB achievement of 203kg.

Mid-size C-class AVC using advanced steel technologies is targeted to match the kerb weight of current B-class vehicles

By concentrating its efforts on the popular midsize family hatch, AVC aims to reduce its kerb weight to 950kg for the petrol variant (993kg for the diesel variant)950kg or possibly lower, which is comparable to that currently achieved in the even smaller B-class (represented by cars such as the Vauxhall/Opel Corsa and Ford Fiesta).

The ULSAB-AVC programme has selected the Ford Focus as the benchmark C-class vehicle to represent current safety standards. The Focus 1.8-litre five-door model has a typical class kerb weight of 1,223kg. The Peugeot 206 from the smaller B-class was chosen as a second benchmark, because its kerb weight of 950kg is the same as the ULSAB-AVC C-class target.

A PNGV-class large family saloon provides a third benchmark (similar wheelbase and interior volume as the original ULSAB project), given that the programme concepts also aim to demonstrate that the steel industry can go a substantial way towards meeting the environmental standards stipulated within the US Programme for a New Generation of Vehicles (PNGV) and the European Consortium for Automotive Research (EUCAR) CO2 reduction programme – but without sacrificing safety or cost.

AVC takes holistic approach to the whole vehicle

'The original ULSAB project allowed us to take a holistic approach to the body,' said Frank Walker. 'With AVC we can take a holistic approach to the whole vehicle. And while continuing to pursue our light-weighting targets, the scope of the programme - which includes a large proportion of the vehicle including the body structure, closures, sub-frames and suspension systems - will offer vehicle manufacturers the opportunity to produce a car that also meets the most demanding safety standards.

To comply with what are seen as the increasingly important New Car Assessment Programme (NCAP) occupant protection ratings, carmakers are introducing secondary safety systems into the vehicle thereby potentially reintroducing weight into the primary structure.

Additionally, crash requirements are becoming more stringent, for example, in terms of impact velocity and barrier stiffness. That further suggests the need to strengthen the structure to comply with the latest NCAP test procedures.

Anticipating the likelihood of these tests becoming mandatory in 2004, the ULSAB-AVC programme attempts to set out these requirements to have a common goal and encourage a meaningful debate with the world’s major carmakers.

'Within this framework the consortium is certainly not promoting any extreme concepts,' a spokesman said. 'On the contrary, it aims to promote ideas that hopefully will achieve the appropriate balance for socially responsible cars for the 21st century.'

'If you take a cross-section of future society, I think that what motorists will continue to want to protect is their comfort and freedom of mobility. However, this desire for extra comfort has to be tempered with the need for safety. Additional creature comforts not only add weight, which runs counter to our environmental need to reduce emissions and fuel consumption, but we must be careful to ensure that lightweight vehicles continue to achieve the right levels of crashworthiness performance.'

'Our proposition is that if we can achieve our objective then the carmaker will have a head start in introducing secondary protection mechanisms to further enhance occupant safety. 'If we can achieve that cost-efficiently while keeping a watchful eye on weight, then we should attain our dual goals of the best possible body structure to maximise strength and safety, while minimising fuel consumption and vehicle emissions.'

Getting the balance right between safety and environmental issues … two-thirds of the influence on fuel consumption and emissions relates to factors other than vehicle mass

Another reason for getting the balance right between safety and environmental issues is that weight is but one factor in controlling emissions and improving fuel economy. This is illustrated by two-thirds of the influences on fuel consumption being related to factors such as the driving style, powertrain (engines and transmissions) efficiency and vehicle aerodynamics, while approximately a third relates to vehicle mass.

The objective for the steel industry of the AVC programme is to help produce concepts that will allow the optimum design of a vehicle taking into account the need for careful balance between driver and passenger comfort and safety, vehicle performance and environmental impacts.

AVC programme will help carmakers build safer vehicles … that are also fuel efficient

Carmakers are working continually to improve vehicle crash performance. The ULSAB-AVC programme will provide valuable engineering input that will add to their automotive customers’ effective use of steel in building safe vehicles.

ULSAB-AVC steel concept designs will be subjected to a mix of six computer-simulated crash events comprising front, rear, side and roof impacts, which represent expected future requirements that are far more demanding than those applied to cars driven today. In effect the programme is a technology demonstrator for advanced steels and new manufacturing processes that will help carmakers meet the world’s toughest safety standards.

According to professor Jon King, director of Corus Automotive Engineering, the fact that most cars are made of steel is because it’s the benchmark material for designing safe vehicles in high volume production: 'Steel is a material with a unique, inherent capacity to absorb an impact and thus diffuse crash energy. Steel can be engineered to collapse in a controlled manner. Steel also has the ability to become harder when crushed, which means it becomes stronger on impact, allowing the steel to absorb more energy.'

'The challenge for the automotive engineer is to optimise how much structure is required to achieve the right level of crashworthiness – which may increase the weight. The ideal now is not more structure in the vehicle but better, more intelligent structures.'

Safe Steel campaign

The AVC programme results from the steel consortium’s desire to continue the work of the ULSAB, ULSAC and ULSAS programmes.

'Following four years of close technical co-operation, we realised we had achieved a remarkable partnership throughout the steel industry that we shouldn’t throw away,' said Frank Walker reflecting on a preliminary meeting held in Yokohama last year. 'We started talking about possible drivers for the future; what were going to be the really powerful motivators for 2004 and beyond. We had a vision of a socially responsible vehicle and that despite it being a new millennium people would be less than enthusiastic to give up their personal freedom of movement.'

'So our future vision reflects the need to maintain individual mobility, to minimise the impact of the sustainability of that lifestyle on the environment, and to do so whilst retaining the affordability of vehicles as an essential pre-requisite, while concentrating particularly on not doing anything within that overall framework that would affect vehicle safety.'

'That is how we formulated the ‘safe steel’ campaign – an acronym that stands for safety, affordability, fuel economy and eco-friendliness.'

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