What is the binding force

1. First take the whole, take the moment for point a, then take the right half as the research object, take the moment for point C, and combine these two equations, then the horizontal and vertical constraint reaction of the right bearing can be obtained. Finally, taking the whole structure as the research object, taking the horizontal and vertical force balance, the two constraint reactions of a bearing can be obtained.

2. According to the balance relationship between force and moment, the distributed load section can be simplified to the load center, that is, the force of QA acting on the midpoint of BC< Then assume that there is an upward force Fay at support a and an upward force fby at support B. for the moment balance of point a, we can get
QA * (a + A / 2) + QA ^ 2 = fby * a, and find that fby is equal to 5qa / 2. For the balance of force, the upward force is equal to the downward force
that is, Fay + fby = QA, and Fay = - 3qa / 2, so the actual direction of Fay is downward

3. The calculation of binding force is often related to specific problems. The general calculation method includes de binding and adding force. For statically indeterminate structures, it is necessary to supplement the corresponding displacement continuity or deformation compatibility conditions.

4. According to engineering mechanics, the bearing binding force of each beam:
(b)
a-end shear force: FQA = fsin30 °+ Q * 1m = - 0.5f + Q (make the isolator rotate clockwise)
a-end bending moment Ma = fsin30 °* 1m + Q * 1m * 1.5m = f / 2 + 1.5Q (pull up and press down)
a-end axial force Na = - f * cos30 °= √ 3F / 2 (compression)
(c)
support reaction at B FB = (f * 3A + M-Q * a * A / 2) / (2 * a) = 3F / 2 + 2m / a-qa / 4 (upward)
reaction at X direction at a fax = 0
reaction at Y direction at a Fay = F + QA FB = - F / 2-2m / A + 5qa / 4 (upward)

5. 1. When I was in high school, the plane problem was regulated as follows: the couple that makes the object rotate counterclockwise is positive, and the couple that makes the object rotate clockwise is negative
2. Theoretical mechanics determines the direction of couple according to the right-hand screw rule. The specific method is to bend the four fingers of the right hand, so that the rotation direction of the fingers is consistent with the rotation direction of the couple, then the thumb points to the direction of the couple
in the simplification of plane force system, you can specify the positive direction first. For example, if the positive direction of the coordinate axis is positive, then the direction judged according to the right hand rule is the same as the positive direction of the coordinate axis, then the couple is positive, otherwise it is negative
3. In the mechanics of materials, it is positive to make the two ends of an object incline upward, and negative to make the two ends of an object bend downward.

6. First of all, you should be able to calculate the shear force and bending moment, and remember that "the upper left and the lower right, the shear force is positive. Then write the shear force equation and bending moment equation. Remember FS, m chart feature table! No load section, uniform load, concentrated force, concentrated couple four graph features are OK! It's very simple! A lot of steps is the kind of one plus one belt!

7. First, according to the force balance, horizontal and vertical force balance, and then according to the moment balance. If it is statically indeterminate, then force method or displacement method!

8.

take the whole:

∑ FX = 0, NaX + p-ne.cos45 degree = 0, (1)

∑ FY = 0, nay-q.2a-ne.cos45 degree = 0, (2)

∑ Ma = 0, M & # 39- Pa-2q. A ^ 2 + m-ne.2a = 0, (3)

take CD, de: ∑ MC = 0, - ne.2a + M = 0, (4)

to solve the above four equations simultaneously, we can get: four reaction forces NaX, nay, NE, M & # - 39

* if the solution of a reaction force is negative, the actual direction of the force is opposite to that in the figure

9. Find the reaction force of support a (let it be both upward and downward), that is, take the moment for point B, and set the positive and negative moment (if clockwise is positive), and set up the moment balance equation, which can be solved. The bearing reaction is positive, which is in the same direction as the original assumption; The bearing reaction is negative, which is opposite to the original assumption
for example: find FRA, set upward, set clockwise as positive, and take moment for point B
fra × 6-q × six × 3 + 2) + me = 0
the solution is FRA = [q] × six × 3 + 2) - me] / 6
calculate FRB, set upward, set clockwise as positive, and take moment for point a
- FRB × 6+q × six × 1) + me = 0
and FRB = - [q] × six × 1+Me]/6

10. Did you learn it? Why not< Suppose you are new to learn:
draw the up reaction RA and Rb of supports a and B.
the external force of the structure takes moment balance for B: 6 ra - 15 + 24 = 0, RA = - 3 / 2 (KN) (down)
the external force of the structure takes moment balance for a: 6 RB - 24 + 15 = 0, Rb = 3 / 2 (KN) (up)