Tham khảo tài liệu 'crc press - mechanical engineering handbook- mechanics of solids part 9', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 1-80 Section 1 Shear Stresses in Beams Transverse loads on beams are common and they cause transverse and complementary longitudinal shear stresses in the beams. Schematically the transverse shear stresses are distributed on a rectangular cross section as shown in Figure . The shear stress is zero at free surfaces by definition. area A FIGURE Transverse shear stress distribution. The internal shear stress is calculated according to Figure from T VQ It where t shear stress value at any point on the line - at a distance y from the neutral axis V total shear force on cross-sectional area A Q y A A area above line - y distance from neutral axis to centroid of A I moment of inertia of entire area A about neutral axis t width of cross section where t is to be determined This shear formula gives Tmax V A if t is constant for the whole section rectangle . Note that the magnitude of the shear stress distribution changes sharply where there is an abrupt change in width t such as in an I-beam Figure . FIGURE Shear stress distribution for I-beam. Shear Flow In the analysis of built-up members such as welded bolted nailed or glued box beams and channels a useful quantity is the shear flow q measured in force per unit length along the beam VQ I
