Consider the following statements in respect of thin cylindrical pressure vessels subjected to internal fluid pressure:
1. State of stress along the vessel thickness is biaxial except on the inside surface.
2. Circumferential stress is twice the magnitude of longitudinal stress.
3. Hoop stress and longitudinal stress remain constant along the vessel thickness.
4. Circumferential welded seam is likely to be weaker as compared to longitudinal seam.
Which of these statements are correct?
(a) 1 and 2 only (b) 2 and 3 only
(c) 1, 2 and 3 (d) 2, 3 and 4