Best software for strength analyses?
One good redneck as I. Why, In strenght analysis is impossible to predict all load which can happen in part or construction lifetime. We are witnesses that investors demand lower prices, material in ours construction is about 75% of price, less material less price. Next fact is that we are forced that construction must work in plastic area, yes, - results show that a strength is good but what will be happened when you load again construction to plastic area. in most cases they will be broken. If someone will die , responsability is going to our soul and... You must imagine that situation when you give a written answer that construction is good and fullfill a design considerations. Strength analysis is only a tool but it gives a results that you must give a final assessment. When you a in a doubt it is necesery to consult with other members of team and higher instances.
Femap, Siemens`s monster child based on NX Nastran engine...see some examples on YouTube and decide your self
Nastran is a beast but unless you have the training it will likely not be worth the effort. SolidWorks with CosmosXpress is ok for estimations but if you need real working informating its calculations and ability to define the system well (depending on complexity) is not sufficient. I have used SolidWorks Simulation and Ansys for analysis of parts and assemblies in some cases using both to see the difference. Ansys is definately the more powerful of the two in my opinion but SolidWorks simulation is by no means weak.