Long term effects of repetitive axial loads on DH pipes and their importance for service life

Today's district heating networks will be used for a long time, provided there will be an efficient and selective replacement of worn parts based on correct methods for status determination and service life prediction. We know the effect of temperature and recently that mechanically stressed pipes degrade significantly faster.

In this project we intend to investigate long term effects of cyclic mechanical loads on the rate of degradation and to develop a new model for calculation of life predictions that takes into consideration combined effects of high temperature and repetitive axial loads.

A basic knowledge of digitalisation, the relationship between different stress levels and the rate of degradation will be gained of laboratory experiments. The effects of mechanical stress will also be evaluated from field tests.

An important part will also be cooperation and exchange of experience regarding ageing and lifetime prediction with experts both within the country and internationally.