Principal Consultant, Peter van Manen offers tips to get a head start on damage from deterioration
Detecting deterioration early is the key to a longer (asset) life. But acting early, while something still has much to give, can be an expensive luxury. The trick is to understand the environment, duty cycle and failure modes well enough to be able to get a head start on damage.
But it isn’t easy measuring deterioration directly. You don’t see the build-up of stresses and strains until it is too late, so you choose between replacing or repairing things that are still working perfectly, or waiting until the cracks or catastrophe appear.
We use mathematical models to help us manage deterioration. Models of the physical thing and probability to deal with uncertainty. In gas turbines, we use the temperature of the hot gases as a surrogate for accumulated damage of the expensive turbine blades. These blades will normally fail by combined creep and fatigue. We count the damage cycles whenever the turbine is running or standing idle and predict when the blades might fail. And then replace them before they do so.
The temperatures are measured and recorded in the control system of the turbine. The accumulated blade damage is calculated in real-time, providing an immediate measure of deterioration.
Developing this approach took time, with a lot of detailed analysis, testing and modelling. But the outcome is pretty special. The high cost of replacing blades across a global fleet of gas turbines is greatly reduced, without increasing any risk of harm. And we return five times the investment in under five years.
We sense trouble well in advance while it is easily remedied.