Bolt Science Web Site

BOLTCALC

Training Presentations

A series of training presentations, including video and PDF guides have been created to show how the BOLTCALC program can be used to solve common bolting problems. If you have any question regarding the presentations or the BOLTCALC program - please contact info@boltscience.com

Torque Analysis

Presentation on a Torque Analysis - Metric Units

Presentation on a Torque Analysis - Inch Units

YouTube Video on a Torque Analysis - Metric Units

YouTube Video on a Torque Analysis - Inch Units

Screenshots of a Torque Analysis - PDF

Thread Stripping Analysis

A couple of case studies looking at a bolt being secured into a blind hole. The tapped hole is in a part made from spheroidal graphite cast iron with a certain length of thread engagement. As part of weight reduction proposals, aluminium instead of cast iron is being considered for the tapped hole material. The question the engineer is considering is whether the thread engagement length used on the cast iron part will also sufficient to prevent thread stripping of the aluminium from occurring. More details are available at:

Thread stripping analysis - metric bolt.

Thread stripping analysis - inch bolt

Joint Analysis

The first presentation covers a simple analysis using BOLTCALC, it presents an example of a basic bolted joint analysis using the BOLTCALC program. Metric units and thread sizes are used in this presentation, and shows how the BOLTCALC program can be used to check whether a bolted joint will be capable of sustaining the applied forces.

The example shown is a basic joint analysis of a simple joint, more complex joints can be modelled using BOLTCALC. Which is shown in some later examples. The analysis is of a seat securing joint on a roller coaster that must sustain dynamic forces. To prevent self-loosening, wear and fatigue, the joint must not slip, nor the plates comprising the joint separate.

An analysis of a joint consisting of M10 bolts (metric units)

Bolt Loosening Case Study

Self-loosening of bolts and nuts is extremely common. In some situations it is an inconvenience, in others, disasterous consequences can arise. When bolts do come loose, it is due to specific causes, address those causes, and loosening will not occur. The link presents a case study investigating the reason why bolt loosening was occurring on a drive sprocket on a tracked vehicle.

Essentially, research indicates that self-loosening is the result of insufficient bolt preload to prevent joint movement when the forces applied to the joint and relaxation losses are taken into account. What this case study does is to investigate whether there is sufficient bolt preload to prevent joint movement. In general for the vast majority of joints, prevent joint movement from occurring and self-loosening won't occur.

Loosening Case Study (metric units)

Loosening Case Study (inch units)

Clevis Joint Analysis

A clevis type joint consists usually of two parts, a rod or member that is trapped between two supports. Such joints are used to transmit primarily shear loads. There are a wide range of uses of such joints, the one shown in the image consists of a spring on a vehicle suspension being secured between two supports. There must initially be a gap between the bush in the spring and the supports to allow it to be installed.
The gap is closed by tightening the through bolt so that there is metal to metal contact through the joint. Accordingly, the gap is usually small so that the force needed to pull the plates together is achievable and that the supports are not over-stressed by the clamp load from the tightening process.

The joint that under study transmits the load using friction grip. In the application, bolts had been found to fail by fatigue. The joint analysis performed here looks at the cause of the failure and how it may be fixed.

Analysis of a Clevis Joint

Further Information