 energy absorption

# Industrial

### Rotational Impact Kinetic energy to be absorbed Energy due to drive force Total energy to be absorbed ET = Ek + Ed Maximum impact force Design mass for buffer #### Summary of notation

To avoid confusing conventions within calculations always use SI units in formulae then convert to more appropriate units if required.

 Notation Quantity SI Unit M Mass of body kg Me Buffer design mass kg S Buffer stroke m K Radius of gyration m Ek Kinetic energy J Ed Energy due to drive force J Et Total energy J ω Angular velocity rad/s I Moment of inertiaa kg.m2 T Torque Nm F Impact force N N Number of buffers in parallel – ξ Efficiency -

#### Worked example

Eg. Consider a swing bridge, having a moment of inertia (I) of 7500000 kgm2, buffer arm radius (r) 8m, angular velocity (ω) of 0.174 rad/sec and a driving torque (T) of 1500000 Nm. Using 2 buffers.

To find the energy to be absorbed: Let us select a Type 4 with 114mm stroke: Total energy to be absorbed:
Therefore ET = Ek + Ed = 113535 + 21375 = 134910 J = 134.91 kJ

To find the maximum impact force: §To find the equivalent mass for metering pin selection: Therefore select metering pin code 08 for masses up to 80000kg (80 tonnes).