# Torque tube sizing for stiffness

• sierramog
In summary, you can use various online calculators to determine the necessary dimensions and strength of the components for the adapter to secure a container to off road moving dolly. It is important to consider dynamic loading and keep the weight of the adapter low.
sierramog
Hi All,
Sorry for the cross post, I had an earlier version of this in Classical Physics which has errors. Please disregard.

Problem Description:

The drawing shows an adapter to secure a container to arms which connect to an off road moving dolly (not shown). A 6x6 beam has two arms (6" deep and 2" wide) welded to the ends that support the container at the sides and two opposing arms (4" deep and 8" wide) offset 2' toward the center that connect to the dolly. The dolly has air bags and shock absorbers. The dolly axle (8000 lb max) is 4 feet from the end of the container. The container side arms are pinned to the bottom corner sockets. Chains hooked to the container top corners connect via chain binders (not shown) to a 7/16" cable routed through guides on the arms and under the container. The cable should never contact the bottom of the container. It is strictly anti torque. This arrangement keeps the arms secure to the sides of the container. The concept is to let the cables oppose the twist but not load the bottom of the container. This arrangement twists the beam in the two foot section between the ends and the dolly connection arms. The support assumes positive g's. The moving dolly axles can support 8000 lbs at 4 feet from the container which I translate to 16000 ft lbs of torque on each arm.

It is important to keep adapter weight low.

Questions:

1. How can I determine if a 6x6x1/4 inch hollow mild steel tube that is 8 feet long is stiff enough to keep beam twist low (one degree will move the axle about an inch) at 16000 foot lbs of torque?

2. How can I determine how much the square tube could rotate (radians) per foot length to provide a safety factor of 5 at 16000 foot lbs of torque?

3. How do I determine the length of the outer arms to minimize the required strength of the anti torque cables?

Hope I have stated the problem correctly.

#### Attachments

• torque tube support.jpg
26.8 KB · Views: 528

## 1. How do I determine the appropriate size for a torque tube for my project?

The size of a torque tube depends on various factors such as the material used, the desired stiffness, and the operating conditions. It is important to consult with a structural engineer or use engineering software to calculate the required size for your specific application.

## 2. What is the relationship between torque tube size and stiffness?

The size of a torque tube directly affects its stiffness. A larger diameter or thicker wall will result in a stiffer torque tube, while a smaller diameter or thinner wall will result in a more flexible torque tube.

## 3. Can I use a smaller torque tube if I increase the wall thickness?

While increasing the wall thickness will increase the stiffness of a torque tube, it is important to also consider the material's weight, cost, and manufacturing limitations. It is best to consult with an engineer to find the most suitable size for your project.

## 4. What are some common materials used for torque tubes?

Some common materials used for torque tubes include steel, aluminum, titanium, and carbon fiber. Each material has its own unique properties and cost considerations, so it is important to select the most appropriate material for your specific application.

## 5. How do I ensure the stiffness of my torque tube meets my design requirements?

The stiffness of a torque tube can be verified through testing or analysis. It is important to accurately simulate the loading conditions and use appropriate testing methods to ensure the torque tube meets the desired stiffness requirements.

• Mechanical Engineering
Replies
15
Views
3K
• Mechanics
Replies
1
Views
2K
• Mechanical Engineering
Replies
7
Views
3K
• Mechanical Engineering
Replies
8
Views
2K
• Mechanical Engineering
Replies
2
Views
1K
• Engineering and Comp Sci Homework Help
Replies
10
Views
2K
• Mechanical Engineering
Replies
7
Views
2K
• Mechanics
Replies
9
Views
1K
• Mechanical Engineering
Replies
1
Views
3K
• General Engineering
Replies
2
Views
2K