# Simple static load problem giving me hell (sketch provided)

• FreeBodyDiag
In summary, the person is facing a design evaluation problem and is using software to find solutions for the loads at different pins. However, the solutions provided by the software do not make sense and do not match with the hand calculations. The person is questioning the validity of the software's solutions and is wondering if they are missing something or if the software is incorrect.

## Homework Statement

This is not actually a homework problem but a design evaluation problem I have encountered.
I am trying to solve for all the loads at the pins and have used WorkingModel to try and give me some quick answers. However, the solutions offered by the software do not make sense to me/can't verify with hand calcs.

The image below shows the values of Fx, Fy and F as calculated by the software at each pin. I have added the co-ordinates of where the pin joints are and where the load acts (in mm). +X is to the right, +Y is to up. The load acting on this system is a 10kgF acting directly down as shown. Each grid square is 50mm wide. The mass of the elements is set to zero.

[PLAIN]http://img833.imageshack.us/img833/7528/forces.jpg [Broken]

The unknowns are the reaction forces (Fx, Fy) at each of fixed pins 11 and 3 and the force acting on the pin at 13.

## Homework Equations

Ʃ forces in X direction = 0
Ʃ forces in Y direction = 0
Ʃ moments about any point = 0
M=F.x
cos(θ)=A/H
sin(theta)=O/H
tan(θ)=O/A

## The Attempt at a Solution

Unless I have severely overlooked something, I immediately dismiss the solutions offered by the software because a simple check of the equation:

Ʃ forces in X direction = 0
...reveals that this is NOT the case.

Ʃ forces in X direction = Fx@pin11 + Fx@pin3 + Fx@LOAD
= (-5.186) + (16.305) + (0)
≠ 0!

??

What is going on here? Am i going loco or is this solution just plain out wrong?

Thanks

Last edited by a moderator:
(hand calc removed because of error)

Last edited:

## 1. What is a simple static load problem?

A simple static load problem involves calculating the forces exerted on a structure or object that is not in motion. This can include finding the weight, tension, compression, or other forces acting on the object.

## 2. How do I solve a simple static load problem?

To solve a simple static load problem, you will need to identify all the forces acting on the object, draw a free body diagram, and use equations such as Newton's laws of motion or equilibrium equations to solve for the unknown forces.

## 3. What information do I need to solve a simple static load problem?

To solve a simple static load problem, you will need to know the weight of the object, the direction and magnitude of any applied forces, and the properties of the object such as its shape and material.

## 4. What are some common mistakes when solving a simple static load problem?

Some common mistakes when solving a simple static load problem include not properly identifying all the forces acting on the object, not drawing an accurate free body diagram, and using incorrect equations or not setting up the equations correctly.

## 5. Can I use software or calculators to solve a simple static load problem?

Yes, there are many software programs and online calculators available that can help you solve a simple static load problem. However, it is important to understand the concepts and equations used in these tools to ensure accurate results.