Tham khảo tài liệu 'the behavior of structures composed of composite materials part 9', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 231 The terms are omitted in the above for brevity and 2 . - Af. b. Stresses in each lamina are calculated at two axial locations to show the stress distributions that occur in the bending boundary layer. Stresses are calculated at an axial location where the deflection is on half of the imposed edge displacement . w- 2 . Secondly stresses are calculated at an axial location of x l 2 where l is the axial distance at which w 0 nearest to the end of the shell. Results are shown in Figure . It is seen that the ÍT stresses are tensile on the outer layers and compressive on the inner layers. It is also seen that the circumferential stresses a. are maximum in the I yij layers which is logical because the circumferential stiffness is greatest in these layers and hence the circumferential load is carried in the 90 layers analogous to a stiff spring in a collection of parallel springs. Lastly even though the deflections and stresses are axially symmetric in-plane shear stresses do exist because of the stacking sequence of the laminate. 232 FIGURE . Stresses at selected points and or displacements within the bending boundary layer Sample Solutions EFFECTS OF SIMPLE AND CLAMPED SUPPORTS Consider the circular cylindrical shell composed of a transversely isotropic composite shown in Figure typical of many RTM fabric composites today. The end of the shell x 0 is simply supported the end x L is clamped. The ends of the shell are assumed to be rigid plates. The internal pressure is and .Ip I is written simply as V in this example. The following information is desired 233 a. What is the magnitude and exact location of the maximum stress that occurs in the bending boundary layer at the simply supported end b. The same information near the clamped end c. What is the magnitude of the maximum stress occurring outside the bending boundary layers say at x L 2 d. If the maximum principal stress failure theory is used would the shell be structurally sound if in .
