How do you do a bolted joint analysis?
The bolted joint works by inducing an initial clamping force (“preload”) on the joint by threading the fastener into either a nut or into threads that have been tapped into one of the parts….Preload Uncertainty.
| Tightening Method | Accuracy |
|---|---|
| Bolt elongation | ±3-5% |
| Strain gages | ±1% |
| Ultrasonic sensing | ±1% |
What are the basic components of bolted joints?
Clamped bolted joints are often used on pipe flanges, automotive engines and chemical reactors. In all of these applications, the bolted joint has three mechanical components: the flange parts, the fasteners (bolts and nuts), and the seals or gaskets.
How do you design a bolt size?
A typical rule of thumb . . . Use a bolt diameter that is 1.5 – 2.5 times (up to three times) the thickness of the thinner material you are bolting together. So, for 1/8″ material, a 1/4″ diameter is often a good bolt choice. For 1/4″ thick material, perhaps a 3/8″ or 1/2″ bolt.
How does a bolted joint work?
When fastened, the bolt is stretched (just a little) to create clamp force. This is called elastic stretching. Elastic stretching provides tension in a bolted joint. When a nut is over-tightened, the bolt can stretch beyond the elastic limit and become permanently deformed.
How are bolt loads calculated?
The tensile load a fastener can withstand is determined by the formula P = St x As. To find the tensile strength of a particular bolt, you will need to refer to Mechanical Properties of Externally Threaded Fasteners chart in the Fastenal Technical Reference Guide.
What are the failure modes of bolted joints?
The Failure of Bolts and Bolted Joints, in particular, can be a significant source of concern for engineers….Excessive bearing stress under the nut face, bolt head, or within the joint itself.
- Insufficient Joint Clamp Force.
- Bolt Thread Stripping.
- Bolt Fatigue Failures.
- Bolt Overload.
- Excessive Bearing Stress.
What tools are needed for bolts and nuts?
Wrenches are essential tools used to tighten and loosen fasteners, like nuts and bolts.
How do bolts work?
Bolts often rely on axial force causing sufficient friction at the threads to remain in place. A torque is applied to the head to generate this axial force. The force acts between the bolt head and whatever the bolt is screwed into, whether that is a nut or one of the parts being fastened.
How long should bolts be?
Many studies have found that there is a simple rule of thumb for standard pitch fasteners. The depth of a fastener should be at least two times its nominal diameter. For example a 1/4in (0.25in) fastener should be threaded at least 1/2in (0.50in) deep.