# Torque Calculation to Open A Door

1. Aug 23, 2010

### yanikomer

Lets assume that we have a door, we know its weight, its geometry, we can calculate its inertia. It is a side opening door, from the materials for the hinge parts we can find the needed friction torque.

We want the door to be open for example 110 degrees in 4 seconds. what are the other calculations that we have to do in order to obtain a torque that is needed to open this door ?

Thanks very much...

2. Aug 24, 2010

### a.mlw.walker

power is torque times rotational velocity, power is also work done * rotational velocity in rads/s, i havent thought to hard about it, but surely that brings into account, speed, you can calculate the distance moved from the width of the door, and the angle you want to move it through - work done, torque is in there, and torque is just the force required to move the door times the distance from the pivot, shouldnt be that difficult from now

3. Aug 24, 2010

### john.phillip

I suggest you to adopt linear angular acceleration\deceleration phases with constant angular velocity in-between and ignore energy losses related to the interaction with the surrounding air or other fluid, hence considering the only parasitic resistance to movement is the hinge friction.

Assign a time period for acceleration\deceleration phases and deduce the remaining time from the 4 seconds limit, also estimate the angular range for each phase based on the time divisions you assigned.

Calculate both the angular acceleration and the angular velocity to achieve the required 4 seconds.

Workout the required torque to keep the door moving against the friction losses based on the door weight, center of gravity, the hinge parts geometry and material friction coefficient.

Workout the required torque to accelerate the door based solely on the mass inertia and angular acceleration.

Now you can add up both torques for your answer and calculate the required power considering both torques and the maximum angular velocity, if you wish.