×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Are you an
Engineering professional?
Join Eng-Tips Forums!
• Talk With Other Members
• Be Notified Of Responses
• Keyword Search
Favorite Forums
• Automated Signatures
• Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

#### Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

# Wedge Calculations

## Wedge Calculations

(OP)
Hi Guys,

Wondering if someone on here can help me I'm trying to calculate some wedge forces for 2 wedges acting together and the resultant force that comes from the rear of the top wedge. This is for an expanding item. I have attached a sketch which may make more sense.

Ian
Replies continue below

### RE: Wedge Calculations

Homework not allowed.

### RE: Wedge Calculations

(OP)
Hi Jboggs, thank you for the reply however it is not a productive one. This isn’t homework it’s something I’m trying to calculate for work.
Do you know how to do this?

### RE: Wedge Calculations

We have to assume that all friction is dynamic friction as a start. For certain if this was homework that should have been a given.

One problem is that, by specifying the 300 kN (little k, capital N for Isaac Newton) is that unless there is an exact balance the mass will be accelerated upwards, assuming the 300 kN is high enough not to slip backwards. Also, kg is not a force; it needs to be multiplied by G (~9.81 m/sec^2 near the surface of the Earth) to produce the force.

The side force is just the force required to push the weight up the 25º hill with the given amounts of friction on the upper wedge. I think it will require an iterative solution to make a guess, starting with the sideways force that would happen if friction was zero.

If the 300 kN is not enough to cause it to move then the side force could be zero.

### RE: Wedge Calculations

(OP)
Hi 3dDave,

Thank you for the info, to explain a little further which may help.
In the practical application I pull on the bottom wedge using a hydraulic cylinder in the 300kN direction, this moves and pushes the top wedge up, in order to control the movement it pushes against the plate highlighted by the vertical line on the wide side of the top wedge. I’m trying to work out how strong this plate needs to be, in my mind it doesn’t see a lot of force but I’m unsure how to calculate it.

Thank you

### RE: Wedge Calculations

It should be g-sub-c, but I forget which forums have subscript. and g/G was clear enough for the solution space.

#### Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

#### Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Close Box

# Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

• Talk To Other Members
• Notification Of Responses To Questions
• Favorite Forums One Click Access
• Keyword Search Of All Posts, And More...

Register now while it's still free!