[2]재료역학 : 중립축 도심축

 

#중립축 #도심축

#소성중립축 #소성도심축

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용어

#PNA : Plastic Netural Axis

#PCA : Plastic Centroidal Axis

#PBA : Plasitc Bending Axis

​중립축 : Stress 및 Strain이 0이 되는 지점이 중립축

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Before defining neutral axis, just imagine a long rubber (eraser) painted with color. Now bend it by applying load on its centre. You can see that color on top side gets darker and that on bottom side gets lighter. So you can see that top side gets darker because it is under compression and color concentrates. On bottom side, color gets lighter because bottom surface is under tension and color gets dispersed.

It can be seen that 2 opposite surface of an objects are under compression and tension respectively. So if we make stress and strain diagram, it can be seen that at a specific point, stress changes its sign from positive (compression) to negative (tension). Which also means that, at that level, all fibres are neither in tension nor in compression, i.e. strain value is zero.

So neutral axis ( or plane) can be defined as a line passing through point of zero stress value!

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In the above pic a section of a beam is shown. When the beam is subjected to clockwise bending stress on the left face and anti clockwise on the right one the beam will deflect. Under the action of bending stress the upper portion will be in compression and lower in tension. However, along one axis in the middle there will be no stress nither compression nor tension. That axis is neutral axis. No Strain

 

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도심축 : 도형의 중앙이 도심축

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Centroidal axis is any axis passing through the centroid of the body.

It’s not necessary that neutral axis and centroidal axis are always coincident.

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Reference from QUARA.