This is a report founded on a project by Atlas Copco called NYSTAB.  The application Nystab is a calculation program that can calculate the stability of the Rockdrill-rigs made by Atlas Copco. The original version of Nystab is stored in a database from 1997 and the code is made in an old version of Visual Basic. My assignment was to develop the application in to a newer programming environment and make it last better in the upcoming years. The software I decided to use to accomplish this project is C# .NET in Visual Studio and Microsoft Access 2010. All the code is written in C# with some insertions from ADO.NET which helped me to easier connect the code with the database.The coding part was split into two pieces; the first was to develop the application scale done with Windows Forms, the second was to write the code for calculations in the application.

This master thesis consists of the creation of shock absorber models for percussive rock drills. A model of the rock was also developed. These models were connected to existing models of the rock drill to create a complete simulation of the rock drilling process.When the models had been created the rock model was evaluated by comparison with measured values from lab tests. The verified rock model was then used to evaluate the shock absorber models.Four new shock absorber concepts have been developed. Three of these have been modelled, while the fourth have only been sketched and described.The evaluation of the models showed the following:? Simulations of the single shock absorber don?t correlate to reality very well.