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Understanding Composite Bar Angle of Twist: Material Differences Explained
- Thread starter chetzread
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In summary, the angle of twist must be the same for two bars if they are to not come apart at junctions.
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BvU
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For a composite shaft, it is useful if the shaft pieces do not come apart at junctions (like point B) 
. That means ##\phi_1 = \phi_2## !
. That means ##\phi_1 = \phi_2## !- #3
chetzread
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Why?BvU said:For a composite shaft, it is useful if the shaft pieces do not come apart at junctions (like point B)
- #4
chetzread
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why the twisting angle are the same? they are different materials, when same twisting moment applied to them , both of them will have different twisting angle,right?BvU said:For a composite shaft, it is useful if the shaft pieces do not come apart at junctions (like point B)
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BvU
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What about T = T1 + T2 + T3 + ... ?
Can you check how 'twisting moment' is defined ?
Can you check how 'twisting moment' is defined ?
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chetzread
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ok,i noticed that the torsion(moment ) applied on both bar are not the same,but why are the twisting angle same?BvU said:
- #7
BvU
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If they are not the same, then the parts of the shaft have rotated wrt one another. That's not good at all.
Are we talking abouthttp://www.colorado.edu/engineering/CAS/courses.d/Structures.d/IAST.Lect07.d/IAST.Lect07.pdf here ?
Work out (7.10) and (7.11) for your composite bar ABC. Surely, at point B you want ##\phi## from bar AB to be the same as ##\phi## from bar BC at point B ?
I think that's what he means: at point B ##\phi## from bar AB is ##\phi_1## and ##\phi## from bar BC is ##\phi_2##.
Are we talking abouthttp://www.colorado.edu/engineering/CAS/courses.d/Structures.d/IAST.Lect07.d/IAST.Lect07.pdf here ?
Work out (7.10) and (7.11) for your composite bar ABC. Surely, at point B you want ##\phi## from bar AB to be the same as ##\phi## from bar BC at point B ?
I think that's what he means: at point B ##\phi## from bar AB is ##\phi_1## and ##\phi## from bar BC is ##\phi_2##.
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chetzread
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so, the torsion here don't allow the parts of the shaft have rotated wrt one another?BvU said:
It's not stated in the question, how do we know that?
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BvU
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They mention a (one) composite shaft - not two separate shafts that happen to be in each other's neigborhood. . So they are welded (or glued or screwed, or ..) together.
FAQ: Understanding Composite Bar Angle of Twist: Material Differences Explained
1. What is the definition of "angle of twist" in composite materials?
Angle of twist is a measure of the amount of rotation that a composite bar experiences when subjected to a torsional load. It is typically represented in radians or degrees and is dependent on the material properties of the composite.
2. How do material differences affect the angle of twist in composite bars?
Different materials used in composite bars have varying stiffness and strength properties, which can impact the angle of twist. For example, a stiffer material will experience less angle of twist compared to a more flexible material under the same torsional load.
3. What are the main factors that influence the angle of twist in composite bars?
The main factors that affect the angle of twist in composite bars include the material properties, cross-sectional shape and size of the bar, and the magnitude and direction of the applied load. Additionally, the type of composite manufacturing process used can also impact the angle of twist.
4. How is the angle of twist calculated for composite bars?
The angle of twist can be calculated using the torsion equation, which relates the applied torque, material properties and geometry of the bar to the angle of twist. It is important to note that the angle of twist is a function of the length of the bar, so longer bars will experience a greater angle of twist compared to shorter bars.
5. How can understanding the angle of twist in composite bars benefit the design and engineering process?
Understanding the angle of twist in composite bars is crucial in designing and engineering efficient and reliable structures. By predicting and controlling the angle of twist, engineers can ensure that the resulting structure will have the desired performance and meet safety requirements. This knowledge can also help in selecting the most suitable materials and manufacturing processes for a given application.