VEHICLE BONNET

Assembly of large metal components, typically the lightly stressed panels of motor vehicles - bonnets, boot lids etc. 

Silicone gels have also been used effectively to protect automotive electronic modules in the severe environment under a vehicle bonnet, where hazards include high temperature, water and salt from road surfaces. 

For every 1 million vehicles the total savings achievable by replacing steel bonnets with plastic amounts to 23(X)0 tonnes of crude oil, considerably more than the energy content of the plastic bonnets. In Western Europe in the mid-1990s there are 130 million passenger cars with an average life le of 160000 km. 

For consumers, natural fibre composites in automobiles provide better thermal and acoustic insulation than fibre glass and reduce irritation of the skin and respiratory system. The low density of plant fibres also reduces vehicle weight, which cuts fuel consumption [72]. Alves et al. [73] studied the life cycle assessment (LCA) analysis of the replacement of glass fibres by jute fibres as reinforcement of composite materials to produce automotive structural components in the structural frontal bonnet of an off-road vehicle (Buggy). 

Complete body shells in plastics are not a feasible proposition due to the lack of torsional stiffness which is proportional to modulus (E) x thickness (t). Plastics materials have E-values 20 to 300 times less than steel (Table 15.6). Hence, plastics in the form of panels are considered more of a practical proposition, i.e. as secondary structures, for example bonnets and boot lids. The important parameter for panels is the flexural rigidity which is proportional to E x t. In this case the ratio of thickness of plastic to steel for equal flexural rigidity is more favourable at between 2.7 and 7. On this basis several plastics could become candidates as indicated in the table. It is a matter of judgement by the designer to what extent panels less rigid than steel will be technically satisfactory and acceptable to the vehicle users. Likewise, an assessment is required of toughness characteristics, impact, and puncture resistance (ref. 1). 

The health, safety and environment manager described to me how, despite a policy which forbade employees riding on the bonnet of certain of its vehicles, an employee was killed doing just that. There was considerable evidence that, despite the policy, the practice of free-riding was in fact widespread. Following the death, he said, everybody was going back looking for documentary... 

The harshest conditions of all are experienced in the engine compartment. In the average car however the total running time is typically only 5000 hours. The trends of low bonnets, reduced air flow and under-engine protection all increase the ambient temperature. The highest temperatures occur when the vehicle is standing after high-load use. 

During measurement of the corneal sensitivity with the Cochet-Bonnet aesthesiometer in both albino and pigmented rabbits the pressure base values for untreated, physiological saline solution treated, or vehicle solution treated animals was approximately 5 g/mm. In Beagle dogs the mean pressure to elicit a blink reflex was higher than in rabbits and reached approximately 9 g/mm. In human volunteers, where the subjective notification of the touch of the filament tip on the cornea was taken as criterion, pressure base values were much lower than in experimental animals, i.e. approximately 1 g/mm. ... 

Arming The system is armed 20 s after the vehicle is locked and the bonnet, luggage compartment and all doors are closed ... 

DSM Polymers B.V. Ronfalin ABS Applications Varies with grade. Automotive parts (exterior, interior under bonnet). Household goods. Safety equipment. Office equipment. Leisure goods.Transportation (air, sea, vehicles). Public buildings. Industrial pipes. Other Grades anti-static Cd-free colours food contact grades anti-squeak with Silicone oil additive UV stabilized. ... 

---