Fatigue testing of drill rig boom

Sandvik Mining and Construction Oy and Elomatic Ltd together designed a fatigue-testing device for a drill rig boom.

Sandvik Mining and Construction Oy in Tampere, Finland tests the welded structural solutions of its drill rigs in physical tests to verify the results of simulation and to learn more about the structure’s behaviour.  Sandvik selected us to do the mechanical engineering and load dimensioning of the device required to test the drill rig boom. They selected us based on our extensive experience of designing a wide range of testing devices and environments.

Our experience in designing the fatigue testing of large structures was limited when we started the project, so it was natural to look for a partner organisation in this regard. This also meant that we did not have to commit our own design resources to work that is not directly linked to Sandvik products.

– Arto Vento, Sandvik Mining and Construction Oy

We could freely design the testing device to test the structure of the boom and implement the required stress variations. The goal was for the device to be as easy to assemble and inexpensive to produce as possible.  It had to be ensured that the device would withstand the fatigue load cycles without failing. In addition, the space was restricted by the size of the T-slot table in use.

Fatigue-testing devices are typically required to have small tolerances and sufficient stiffness to produce reliable measurement results. In addition to design, we were also responsible for the specification of the fatigue load, in order to achieve the desired cyclic stress on the boom welds. In real use, the booms are exposed to transverse and torsional loads. Therefore, both these loads had to be included in the test load.

The cost of device was kept down by minimising the number of plate sizes and pipes used. The structural solutions were also simple and production-friendly to ensure that many workshops could produce them. This, in turn, facilitated putting production out to tender.

Elomatic had previously worked with demanding structures, so it was easy to start cooperating with them. It also helped that we got everything from them on a turnkey basis, starting from part dimensioning up to procurement. The cooperation was very successful and we have together learnt a lot about fatigue testing.

– Arto Vento, Sandvik Mining and Construction Oy

Together with Sandvik experts, simulation iteration was used to specify the fatigue load direction, magnitude and stroke to achieve the right fatigue load. We succeeded in implementing both the transverse and torsional loads with one load element, which represented a significant saving on the total cost of the device. Experienced Elomatic designers modelled an inexpensive, but durable and safe structure. The durability of the device was verified with static and fatigue simulation.

The boom testing device attached to the T-slot table. 

The Sandvik and Elomatic cooperation has continued on new test device and concept projects.

Sandvik drill rigs – https://www.rocktechnology.sandvik/en/products/underground-drill-rigs-and-bolters/

Elomatic’s technical analysis services – https://www.elomatic.com/en/services/technical-analysis/