Bolt
Science can perform a range of tests on fasteners and bolted
joints to assist organisations in problem resolution, our
test capabilities include:
Torque-Tension
Tests
Determination of the torque-tension relationship for a
threaded fastener allowing the appropriate tightening
torque to be determined. Such tests will allow the nut
factor (sometimes referred to as the torque coefficient
or k factor) to be determined. and the overall coefficient
of friction. By completing several similar tests, the
variation in the torque-tension relationship, due to friction
variation, can be established for an application.
Friction
Determination Tests
Test fasteners can be mounted in a test rig to allow the
thread and head friction torques to be determined. From
these results the thread and nut face friction coefficients
can be determined. These values are of importance to allow
an assessment of what effect various joint surfaces can
have on the bolt torque-preload relationship. Such tests
can be completed, for example, to assess the effect the
introduction of new fastener finishes will have on a joint's
performance.
Torque/Preload
to Failure Tests
Tests can be performed by tightening the fastener to failure.
This can be completed on actual assemblies and/or test
fixtures to allow torque-angle-force characteristics to
be established. From this information torque-angle tightening
specifications can be derived allowing accurate controlled
tightening to be completed. Such tests can also be used
to determine what is the maximum preload that an assembly
will sustain.
Torque
to Yield Tests
Tests can be performed on actual assemblies to obtain
torque-angle graphs that can be used to establish the
torque to reach the yield strength of the bolt. Such graphs
can be used to establish the appropriate torque-angle
specification. They can also be used, with analysis software
such as our BOLTCALC program, to assist in assessing the
structural integrity of an assembly. The advantage of
measuring the applied torque and angle of rotation of
the fastener, is that tests on the actual joint can be
completed without having to change the joint stiffness
by introducing a load cell.
Vibration
Loosening Characteristics of Fasteners
Fasteners coming loose is a common problem across many
industries. We can complete an assessment of a fastener’s
self loosening characteristics using a transverse vibration
test machine (often referred to as a Junker machine).
The fastener preload decay graphs produced can allow an
assessment to be made of a fastener’s resistance
to self-loosening.
Click to View a Video on a Junker Test
A brochure detailing the test and consultancy services that
we can supply is available in Adobe pdf format that can be
viewed by clicking on the image at the side.
If you think that we could possibly
be of assistance to you with our test services, please contact
us.