Robbins management edition 13 video online is full of paragraphs, which need complete HD, and the answer is satisfactory with high scores!
Hello, the full version of Robbins Management 13 video is rare on the Internet. I downloaded it from Key Research Learning Network. It's high-definition and complete, not paragraph by paragraph, but there is no room for video here. Please copy and paste some supporting instructions for you. There are many materials. Just download it directly.
2 shear stress reciprocity theorem
On two planes perpendicular to each other, the shear stress must exist in pairs with equal values, both perpendicular to the intersection of the two planes, and the direction is * * * pointing in the same direction or * * * deviating from the intersection.
B 3 shear Hooke's law
(1) pure shear
If there is only shear stress and no normal stress on both sides of the unit body, this situation is called pure shear.
(2) Shear strain
For a cylinder with a length of 1, the relative torsion angle at both ends is o, and the shear strain is y=ro/ 1.
(3) Shear Hooke's Law
When the shear stress does not exceed the shear ratio limit of the material, the shear strain is proportional to the shear stress, that is, t=Gy, where G is the shear modulus of the material.
(4) the relationship between elastic constants
For isotropic materials, the relationship among elastic modulus e, Poisson's ratio u and shear modulus g is G=E/2( 1+u).
The above two-dimensional code can be directly read from the seventh edition of advanced mathematics teaching video of Tongji University.
Tongji university advanced mathematics seventh edition teaching video full set of topics 3:
Fifth, the concept of torsion of non-circular cross-section bar.
① Basic concepts
(1) Warp: The phenomenon that the cross section of a bar is no longer flat after torsional deformation.
(2) Free torsion: torsion in which both ends of an equal straight bar are subjected to the action of a torsion couple and the warpage is unrestricted.
Deformation and stress characteristics: the warping degree of each section is the same, and the longitudinal fiber length is unchanged; There is only shear stress in the cross section.
(3) Constrained torsion: torsion with limited warping due to stress or constraint.
Deformation and stress characteristics: the warping degree of each section is different, and the longitudinal fiber length between adjacent sections changes; There are shear stress and normal stress on the cross section.
Tongji University Advanced Mathematics Seventh Edition Teaching Video Complete Works Topic 4:
Second, the shear and bending moment
① Shear force
Shear force refers to the internal force resisting the shear action, which is the resultant force of the distributed internal force system tangent to the section.
Symbol stipulates: if the left side has a tendency of upward dislocation or clockwise rotation relative to the right side, the shear force is positive; Conversely, the shear force is negative. The shear force caused by the upward external force of the left beam section is positive, and the shear force caused by the downward external force of the right beam section is positive; On the contrary, it is negative.
For a plane curved bar (the axis is a plane curve and the load acts on the longitudinal symmetry plane), it is stipulated that any point in the curved bar under consideration should take the shear force as the moment, and if the moment is clockwise, the shear force is positive.
② Bending moment
Bending moment refers to the moment resisting bending action, which is the moment of the resultant force couple of the distributed internal force system perpendicular to the section.
The symbol stipulates that the moment of external force acting on the centroid of the section makes the beam convex downward and concave upward, and the bending moment is positive; On the contrary, the bending moment is negative. The clockwise bending moment caused by the external force of the left beam section is positive, and the counterclockwise bending moment caused by the external force of the right beam section is positive; On the contrary, it is negative.
For plane curved bar, the bending moment of increasing axis curvature is positive.
B③ Shear equation and bending moment equation
(1) Shear force (bending moment) equation: the abscissa represents the position of the section on the beam axis and the functional expression of the shear force (bending moment) on each section.
(2) Method: ① Segmenting according to the external force on the beam and its change.
I also gave the notes, and the place where I downloaded them also said that your problem should be solved. If it helps to confirm, please try to come back and adopt the next point. Thank you!