If you are a graduate student or a practicing mechanical/civil engineer, you have likely heard the phrase: "Solids and Fluids are not different subjects; they are just different special cases of Continuum Mechanics."
You will likely find that you already paid for access through your tuition. Continuum Mechanics For Engineers 4th Edition Pdf
The 3rd Edition (Mase & Mase) is available on AbeBooks or eBay for as little as $15 shipped. The page numbers changed, but the tensor derivations have not. You can then use a free online errata sheet to catch the updates. "Continuum Mechanics for Engineers, 4th Ed" is the best "first principles" book for engineers who need to use FEA or CFD professionally. Is the PDF out there? Yes. Is it worth the legal headache and security risk? Probably not. If you are a graduate student or a
Cauchy’s stress principle. You will derive why stress is a tensor and how to find principal stresses without looking at a Mohr's circle. You can then use a free online errata
The hardest part. You will learn index notation (Kronecker delta, permutation symbol). Pro tip: Don't skip this chapter. If you fail tensors here, you fail the rest of the book.
Have you used this text for a course? Drop a comment below about which chapter you found the most challenging—I usually hear "Chapter 2: Tensors" wins that prize.