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You are here: Home / Mechanical Engineering / Solid Mechanics / Mechanics of Continuous Materials / STUDY OF A PRE-TENSIONED BOLT ER420


This equipment investigates the behaviour of a pre-tensioned bolt and allows studies of bolted assemblies.


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

Standard equipment ER420
- 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: EI616
- A ring spanner 24 mm

A torque wrench of capacity 40 - 200 Nm with 24 mm nut