How to calculate the bearing force
Publish: 2021-04-14 18:26:00
1.
The general steps to calculate the bearing reaction are as follows: (1) according to the type of bearing
2. A simple statically determinate structure can establish two equations by force balance and moment balance. Each equation can find an unknown quantity, that is to say, a simple statically determinate structure can only find two unknown forces
for statically indeterminate structures, the calculation is complicated, but the balance and moment balance should be used to establish the equations. In addition, other equations should be added to solve according to the specific situation, that is, as many equations as there are unknown forces
for example, if a simply supported beam is l in length and ab at both ends is simply supported, and there is a P-down concentrated force at 1 / 3L from left to right, calculate the reaction force of supports at both ends
this is a simple statically determinate structure, and the solution is as follows:
let the reaction forces of supports at both ends be RA and Rb respectively
according to the balance condition of vertical force:
RA + RB = P
according to the balance condition of vertical moment, taking a as the origin,
RB * l = P * 1 / 3L (clockwise moment equals counter clockwise moment, a's support reaction force passes through the origin, The solution of the two equations is:
RA = 2 / 3P
RB = 1 / 3P
diagrams are not available here. All books on structural mechanics have calculation methods. It's better to look for them, which is much better than our painstaking explanation here.
for statically indeterminate structures, the calculation is complicated, but the balance and moment balance should be used to establish the equations. In addition, other equations should be added to solve according to the specific situation, that is, as many equations as there are unknown forces
for example, if a simply supported beam is l in length and ab at both ends is simply supported, and there is a P-down concentrated force at 1 / 3L from left to right, calculate the reaction force of supports at both ends
this is a simple statically determinate structure, and the solution is as follows:
let the reaction forces of supports at both ends be RA and Rb respectively
according to the balance condition of vertical force:
RA + RB = P
according to the balance condition of vertical moment, taking a as the origin,
RB * l = P * 1 / 3L (clockwise moment equals counter clockwise moment, a's support reaction force passes through the origin, The solution of the two equations is:
RA = 2 / 3P
RB = 1 / 3P
diagrams are not available here. All books on structural mechanics have calculation methods. It's better to look for them, which is much better than our painstaking explanation here.
3. Draw the support reaction FA and FB, the support reaction FB when all forces are moment balanced to a, and the support reaction FA when all forces are moment balanced to B.
4. This problem can be solved as a whole:
1 Σ Fx=0
2, Σ M＝0
1 Σ Fx=0
2, Σ M＝0
5. /link?url=UT2-w_ IAwWpSWT7uGaOZReQmMOYonVn_ 3pv13 hope to adopt, thank you, in addition, simply supported beam can use static balance, that is, in the vertical direction, the constant equation ∑ f = 0, for the hinge point ∑ M = 0, how to calculate the support reaction
6. First determine the type of support and draw the stress diagram. Write the balance equation again (X-direction balance, Y-direction balance, fulcrum couple balance)
7. Support reaction
is a term in theoretical mechanics, which can also be called constraint reaction of support,
is the support force of a support to the supported object
bearing reaction (1 piece) bearing (including)
(1) movable hinge bearing
(2) fixed hinge bearing
(3) fixed bearing
(4) sliding bearing
calculation of bearing reaction
simply supported beam can be statically balanced, that is,
∑ f
= 0
,
for hinge joint, ∑ M = 0
,
for continuous beam,
, and The statically indeterminate rigid frame should be calculated by force method or displacement method
the calculated vertical force is the fulcrum reaction, and the specific calculation of each support reaction is the calculated vertical force of fulcrum divided by the number of supports
is a term in theoretical mechanics, which can also be called constraint reaction of support,
is the support force of a support to the supported object
bearing reaction (1 piece) bearing (including)
(1) movable hinge bearing
(2) fixed hinge bearing
(3) fixed bearing
(4) sliding bearing
calculation of bearing reaction
simply supported beam can be statically balanced, that is,
∑ f
= 0
,
for hinge joint, ∑ M = 0
,
for continuous beam,
, and The statically indeterminate rigid frame should be calculated by force method or displacement method
the calculated vertical force is the fulcrum reaction, and the specific calculation of each support reaction is the calculated vertical force of fulcrum divided by the number of supports
8. Let me give you a simple answer: first, draw the reaction force RX and ry of the fixed hinge bearing, and the reaction force rby of the movable hinge bearing upward. All the forces on the fixed hinge support are taken as the moment balance equation, and the rby solution is obtained. And then you ask for something else, OK?
9. The calculation of bearing reaction force of simply supported beam can be calculated by static equilibrium, that is, the equation ∑ f = 0 in the vertical direction,
for the hinge point ∑ M = 0,
for the continuous beam, rigid frame and other statically indeterminate, the force method or displacement method should be used
the calculated vertical force is fulcrum reaction, and the specific calculation of each support reaction is the calculated vertical force of fulcrum divided by the number of supports
support reaction
is a term in theoretical mechanics, which can also be called constraint reaction of support,
is the support force of a support to the supported object
judge the direction of bearing reaction force
statically determinate structure: three balance equations can be used to directly calculate the bearing reaction force, and its direction can be assumed at first. For example, the vertical bearing reaction force can be assumed to be up or down, and the calculation result is positive, which means that your assumed direction is correct, and vice versa
statically indeterminate structure: in case of external statically indeterminate structure, the bearing reaction can not be calculated directly, so it needs to be known after solving statically indeterminate structure. For example, the bearing reaction is regarded as unknown force (excess force) by force method, and the direction of excess force is assumed at first. The method of judging the actual direction is the same as the above.
for the hinge point ∑ M = 0,
for the continuous beam, rigid frame and other statically indeterminate, the force method or displacement method should be used
the calculated vertical force is fulcrum reaction, and the specific calculation of each support reaction is the calculated vertical force of fulcrum divided by the number of supports
support reaction
is a term in theoretical mechanics, which can also be called constraint reaction of support,
is the support force of a support to the supported object
judge the direction of bearing reaction force
statically determinate structure: three balance equations can be used to directly calculate the bearing reaction force, and its direction can be assumed at first. For example, the vertical bearing reaction force can be assumed to be up or down, and the calculation result is positive, which means that your assumed direction is correct, and vice versa
statically indeterminate structure: in case of external statically indeterminate structure, the bearing reaction can not be calculated directly, so it needs to be known after solving statically indeterminate structure. For example, the bearing reaction is regarded as unknown force (excess force) by force method, and the direction of excess force is assumed at first. The method of judging the actual direction is the same as the above.
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