Impact Loading on a 2D Reinforced Concrete Beam

Dear all,
 
I have already model a reinforced concrete beam in 2D and I have already assign the properties of concrete and reinforcement. Now I have to apply impact load (a free fall drop weight mass in the midspan of the beam). I know that it is very difficult to create an object that falls on my beam, but I think there is another solution to apply impact loading. I asked a PHD student in my university (Surrey University) and he told me that I have to produce a graph which will be my input data for impact. Can you please let me know if there is any procedure or commands in iDiana to do impact at the midspan of the beam?? I have all the properties of the impactor (weight, falling height, material, dimensions, velocity) but I do not know how to apply it.
This is the topic of my dissertation, to model a beam under impact loading and produce results similar to the experimental ones.
I am looking forward for your reply.
 
Best Regards,
Efstatthios Panetas