Can I justify my PhD if I have mostly adapted existing code instead of writing it myself? My PhD in computational mechanics (field is materials science) involves writing Fortran subroutines for implementing new constitutive equations. More specifically, my research involves continuum mechanics, finite-element analysis and other numerical methods. Though theoretically I have a decent understanding of the subjects, I find it impossible to implement them in code.
I have published a paper on implementing a modified model through a subroutine. But the truth is that I have not written the code from scratch. More than 80% of the code was written by someone else. Here's the original code. I just modified the hardening law to suit my purpose. I did not change the integration method or the structure of the code. I have cited their paper of course.
Truth is, I would not have been able to write the code from scratch even if I had been given five years to do that. I just can think of how to implement theory to code.
Now, I am about to defend my PhD, which is based on this code.
I feel like a charlatan and that I can’t justify my PhD. My advisor doesn’t know this. I am not suited for a career in computational mechanics or materials science. How can I reconcile this?
You weren’t earning a PhD in FORTRAN Coding (gasp – I shudder to think of it). You were working in continuum mechanics. That is where your contribution was, and is.
If I read it correctly, you took an existing tool and adapted it for a new purpose. I can’t find anything wrong with that, especially as you cited the creators of the original version. If you keep it up and continue to make contributions to continuum mechanics you will do fine. You didn’t screw up. You did what any sensible person should do. FORTRAN was my first computing language. I doubt that I would even recognize it anymore.
Relax, have a culturally appropriate beverage and celebrate your success.