Study Of A Pre Tensioned Bolt
Analysis can be made of the stresses and strains produced in a bolt after different methods of tightening, and allows modelling of the behaviour of a bolted connection when axially loaded.
Teaching objectives
The apparatus allows the following experiments:
- Deformations in a bolt after tightening with a spanner or with a torque wrench.
- Effect of bolt pre-tensioning using a hydraulic loading system.
- Effect of varying the loading position.
- Effect of varying the materials on the loading torque.
- Static analysis of sliding with friction on a helical screw contact surface or plane.
- Simple loading and stresses on a plane section.
- Mohr’s Circles of stress, principal stresses and their directions.
Technical specifications
The pre-loaded bolt assembly is composed of :
- A 16mm bolt on which are fixed three pairs of diametrically opposed 45° strain. These permit the measurement of extension and tension in the bolt.
- A tubular component with 2 strain gauges mounted at 180° to measure the compression in the assembly at different heights.
- A loading tube to apply bolt pre-load or to apply loading force at various positions along the bolted assembly.
- A manually operated hydraulic pump.
- A micrometer dial gauge to measure extensions over the complete assembly.
- Nuts and washers of various materials.
Equipment Package :
- Pre-loaded bolt assembly with hydraulic loading system and manual pump.
- A set of washers.
- Technical manual and teaching notes.
Dimensions and weight
- 15 diam. x 37 cm – 12 kg
- Pump: 40 x 10 x 14 mm – 3,5kg
Essential requirements
- Electrical supply : 220V, 50 Hz
Additional required equipment :
- Extensometer bridge.
- A ring spanner 24 mm.
- A torque wrench of capacity 40 – 200 Nm with 24 mm nut.
