I am a final year PhD student in Mechanical Engineering. My PhD comprises only numerical work with a Finite Element Method software, and structural optimization with a developed MATLAB code. I have already a good number of publications, and a few innovations in my project, like structures with a new configuration. However, my supervisor tells me that I need to validate my numerical results with an experimental test. Do I really need to validate my results experimentally to have a "safe" work, I mean, work with results that I can trust? I did a mesh sensitivity analysis for every geometry I have tested.I am sure the mesh is fine enough to obtain converged results. Is it safe to assume the accuracy of the numerical results? And if numerical work alone is not enough, is there any alternative to experimental testing, that would delay my thesis defense and is expensive (allocation of funds is very difficult right now due to crisis in EU?"
I am asking this because I don't have any experience in experimental work, and this will delay my thesis defense 1 year or so. I don't plan on working with anything experimental after my PhD graduation. I would like to have arguments to convince my supervisor that I can do my PhD without experimental work, presenting results in my thesis that are accurate, and that anyone can trust.
I am asking for help of Mechanical Engineering PhD graduates, specialists in numerical work. I would also like to know if you did experimental testing to prototypes in your work, and if not, the arguments you had to defend yourselves in the thesis examination, if you confronted with questions like :"why haven't you done experimental work?"
P.S. I know someone that did his PhD without experimental work, but it was in a different field, like Biomedical Engineering, or so.