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下面是官方实例的具体内容,我做了以后有几点不明白的地方,希望那位高手能给与指点,ths!同时也给与和我同样的新手一次练习的机会。
Overview:
This example presents a textbook type problem relating to a mechanism that is accelerating on a track. The problem requires finding the steady-state position of the mechanism with the given acceleration. Step-by-step instructions are given but do not include GUI help. Model consists of four moving parts and one imposed motion.
Problem:
Links A and B each weigh 8 lb, and bar C weighs 12 lb. Calculate the angle theta assumed by the links if the body to which they are pinned is given a steady horizontal acceleration a of 4 ft/sec^2.
Procedure:
1、Start ADAMS.
2、Create a new model. (Units = ips, Gravity = -y Earth)
3、Set the working grid units to inches.
4、Create main body. Box (length = 22 in., height = 3 in., depth = 1 in.)
Place the box on the working grid with the lower left corner at (-22, -1, 0).
5、Create bar C. Box (length = 22in., height = 2 in, depth = 1 in.)
Place the box on the working grid with the lower left corner at (-22, -19, 0).
6、Create Link A between points (-20, 0, 0) and (-20, -18, 0).
7、Create Link B between points (-2, 0, 0) and (-2, -18, 0).
8、Set the weight of links A and B to 8 lb each. Set the weight of bar C to 12 lb.
9、Make revolute joints between link A and the main body, and between link A and bar C.
10、Make spherical joints between link B and the main body, and between link B and bar C.
11、Make a translational joint in the x direction between the main body and ground.
12、Impose motion on the translational joint. (velo(time) = 48*time).
Add a torsional spring-damper at the revolute joint between link A and the main body. Set the stiffness to 0 and the damping to 10.
The damping will let the system reach steady state in fewer time steps.
Testing the ADAMS model.
Create an angle measure to measure the angle between the main body and one of the links.
Run simulation (end time = 50, steps = 500)
Observe angle measurement when the system reaches steady state.
Solutions:
Theoretical: Theta = 7.1 degrees
ADAMS: Theta = 7.1 degrees
下面左图是原理图,右图是实物图 |
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