The scope of this paper is the study of the crankshaft fatigue
strength under bench tests loads. When a crankshaft is running
inside the engine, it is subjected to radial forces and torsional
moments. These radial forces come from the fuel combustion and are
responsible for the crankshaft bending. The moments occur mainly
due to the torsional vibration phenomenon and are responsible for
twisting the component.
Once there are these two main loads which can damage the
component, both must be considered in the design phase. Moreover,
the crankshafts must be tested under these conditions to guarantee
that they will not fail during engine operation.
The finite element method is used to simulate the bending and
torsional experimental tests before the crankshafts manufacturing.
Fatigue calculations are performed using simulation results to
predict how the crankshafts will fail on the experimental bench
tests.
After the crankshafts have already been approved by the
simulations and prototypes have already been manufactured, the
bending and torsional tests are performed. Hence, the tests results
are correlated with simulations results comparing stress
distributions and stress measurements using strain gauges, which
are applied on the crankshaft surface at specific interested
regions, as well as the predicted position of the failure.
Similar results were obtained from simulations and bench tests,
what indicates a precise correlation once determined rightly the
boundary conditions. In this direction a reduced test can be
applied to validate a new design, saving money and time.