# "Members of a frame are axially inextensible" implication?

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1. Mar 1, 2015

### Ashu2912

In analysis of frames, we say that "The members of the frames are axially inextensible". In context of frames with vertical legs, what I understand is that the length of the chord joining the member ends in the displaced condition would be same in the axial direction. However, what does it imply in frames with inclined legs?

2. Mar 1, 2015

### Staff: Mentor

Same thing. The distance between the ends doesn't change.

Chet

3. Mar 1, 2015

### Ashu2912

This is a diagram I found in "Structural Analysis" by Aslam Kassimalli. Here, if the member AC is inextensible, shouldn't the point c`in the deflected frame lie on the line CD in the original frame?

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4. Mar 1, 2015

### Staff: Mentor

I don't think so. I think that all that is required for AC to be inextensible is that the cumulative length along the line AC be the same as in the original frame.

Chet

5. Jul 10, 2015

### lingesh

" The members of the frames are axially inextensible". does that mean no axial deformation? Doesnt seem to be right..

6. Jul 11, 2015

### SteamKing

Staff Emeritus
Pretty much.

All you've provided is a diagram. Is it being used in your text to help explain a certain mechanics topic, by chance?

Often, in explaining a certain point of mechanics or whatever, a simplified model is used initially to explain the concept. Once enough concepts are understood by the student, more complex (and more realistic) models can be analyzed and discussed in more complete detail.