WBM Gippsland has been using Strand7 to investigate structural deformations that were occurring in their clients' paper roll lifting mechanism.
The bucket mechanism is used to lift three-tonne rolls of paper onto a conveyor system for further handling and processing.
The client identified that permanent deformation of some of the main structural members had occurred over repeated operation of the lift. Some local pull-out of holding down bolts had also occurred.
WBM was contracted to investigate the potential cause of this deformation and devise remedial changes.
Strand7 was used to create a global model with sufficient detail to investigate some of the local stresses close to the bucket hinge and ram points.
The paper bucket is hinged about two support points and lifted via two hydraulic rams.
The model was essentially divided into two zones. The first zone was the area away from the zone of influence. This incorporated the conveyor system behind the main lift bucket. This was modelled using Strand7 beam elements.
The second area, the zone of interest, was modelled in detail with shell elements and the 3 tonne paper roll represented as lumped mass.
A nonlinear static analysis was run. The load increments were chosen such that the bucket was lifted through its full operation cycle by applying appropriate strains to the lifting rams.
The Strand7 model was used by WBM to identify the most appropriate remedial measures to ensure ongoing structural integrity.
The Strand7 consulting service can be accessed in South Africa through Allyson Lawless and Associates.