Coach Side Impact
Vectayn assisted in the development of a double decker coach to meet strong levels of side impact protection. European regulations did not leglislate for coach side impact performance but federal regulations for school buses were applicable:
‘The bus shall withstand a 25 mph impact by a 4,000 pound, post 1973, American automobile at any point, excluding doorways and turntable area, along either side of the bus with no more than three (3″) inches of permanent structural deformation at seated passenger hip height. This impact shall not result in sharp edges or protrusions in the bus interior’.
For test repeatability and comparability, an ECE type, deformable side impact trolley was used as the post 1973 American automobile. The mass of the trolley was increased to 4000lb.
The worst case (maximum deformation) location was found to be on the staircase side of the vehicle with the impact centred midway between the staircase moulding and the forward rear wheel.
Impact analysis of the baseline design showed the structural performance to fall some way short of the required standard with excessive deformation and rupture of the body side
A change in layout to provide increased wheel chair capacity with side mounted folding seats presented the opportunity to use the seat frame to strengthen the side structure but the issue of body side rupture was still evident.
Good side impact performance was achieved through two further changes:
A switch from not structural trim panels to bonded aluminium giving a double skinned side wall, &
The addition of a partition spanning the two main side members and linking to the under floor rail
A change in layout to provide increased wheel chair capacity with side mounted folding seats presented the opportunity to use the seat frame to strengthen the side structure but the issue of body side rupture was still evident.