Tube geometry
Request requires outer and inner diameter, length and tolerances. The wall thickness follows from a matched pair of diameters, but this is still not sufficient to conclude suitability.
Indicate whether the tube is a beam, strut, shaft, housing, or part of a frame. The distance between supports and the location of the load change the problem even if the length is the same.
Load and connection
| Question | What to convey | What is being checked |
|---|---|---|
| How the tube is loaded | Bending, torsion, tension/compression, combination | Work scenario and direction of reinforcement |
| Where are the supports | Pattern, distance and contact areas | Effective length and local loads |
| How to connect | Glue, clamp, sleeve, fastener | Surface preparation and force transfer |
| What's limited | Weight, deflection, outer clearance, inner passage | Geometry selection criterion |
| How to control | Dimensions, edge, straightness, sample | Acceptance of delivery or part |
Tube vs. Rod: Basic Difference
The tube has a cavity, the rod is a solid long form. Choice cannot be reduced to the statement that one option is always easier or tougher. It is necessary to compare elements with the same function, length, supports, restrictions on external size, weight and method of connection.
The internal passage can be functional: another element or communication is placed through it. If a passage is not needed, they still evaluate how the material is distributed relative to the axis and how the ends will be arranged. For compressed long elements, stability is checked separately, and for bending, deflection and local support zones are checked.
Changing the length between supports changes the behavior of the element, even if the diameter and material remain the same. Therefore, a dimension from someone else's project cannot be transferred without checking your own diagram.
Selection order
- determine the function of the tube and the design of the supports;
- fix the outer clearance and the required internal passage;
- describe the load, number of cycles and environmental conditions;
- select and check the connection node;
- agree on length, end finishing and tolerances;
- confirm the solution by calculation or test for a critical problem.
Applications
Tubes are used in frames, beams, struts and other long elements. The practical meaning of the form is to obtain a closed section and place the material relative to the axis of the structure, but the result depends on the structure of the particular tube and components.
For an FPV or robotic design, the tube is not selected in isolation: adapters, clamps, holes, free span and repairability are checked.
Example of a request without a ready-made calculation
The customer can describe the tube as a frame member: specify the overall length and distance between supports, available outer clearance, required internal passage, clamping locations, load direction and allowable deflection. Attach a sketch of the node and note which values are mandatory and which can be changed.
If the diameter or wall has not yet been selected, you do not need to guess it. The request is formulated as a selection by function, followed by confirmation by calculation or sample. For the series, the processing of the ends, markings, completeness and a clear method of incoming inspection are additionally agreed upon.
Selection errors
- compare tubes only by outer diameter;
- do not take into account the length between supports;
- consider the clip or insert to be a secondary part;
- machine an end without consistent edge requirements;
- transfer the result of one node to another load circuit.
Frequently asked questions
What dimensions are needed for the request?
Outer and inner diameter, length, quantity and tolerances, as well as load and connection diagram.
Is it possible to select a wall by mass?
Weight may be a limitation, but the solution requires checking stiffness, load, geometry, and joints simultaneously.
How to connect a carbon tube?
The type of connection is selected for power transmission and maintenance. The geometry of the insert, clamp or sleeve must be part of the specification.
Is it possible to shorten the tube?
Machining is only possible with suitable process and face requirements. Before the series, it is worth agreeing on the control result.
What to specify for FPV design?
Beam/Strut Purpose, Length, Attachments, Components, Weight Limits, and Load Scenario.