Anja
Bioengineer
- Apr 4, 2001
- 7
First of all, I am biologist and know NOTHING about mechanical engineering or finite element analysis - so please forgive my amateur approach.
I would like to model the stiffness of a single plant cell, a pollen tube. It could be described as a fire hose kind of pipe (length up to several hundred micrometers), diameter ca. 6 micrometers, with an apical, half-sphere shaped dome (same diameter tubular part). The other end of the tube is more complicated and irrelevant in this context. This cellular pipe is filled with cytoplasm (for simplicity: homogeneous liquid). The resistance to local lateral deformation consists of 1. the turgor pressure (internal pressure of a living cell), 2. the cell wall (thickness ca. 100-200 nm).
Hypothetical case: The plasticity and thickness of the cell wall is identical at the apex and the remaining part of the cell. How can I calculate the force I would need to locally deform the apical part of the cell (i.e. cylindrical part directly adjacent to the half-sphere), compared to the more distal part (i.e. the purely cylindrical part further down the pipe). A ratio would be good enough (just to know, whether the apical, dome-shaped part would be stiffer or not)!
One more detail: local indentation of the cylindrical part under pressure needs about 20 times the force compared to indentation of the cylindrical empty tube, i.e. the wall only, without pressure.
Any kind of input, also reference to basic engineering literature (textbook? web site?) would be VERY welcome!!
PS: Any substantial calculations and ideas that would make their way into the scientific paper I am trying to write, will be honored with co-authorship!
I would like to model the stiffness of a single plant cell, a pollen tube. It could be described as a fire hose kind of pipe (length up to several hundred micrometers), diameter ca. 6 micrometers, with an apical, half-sphere shaped dome (same diameter tubular part). The other end of the tube is more complicated and irrelevant in this context. This cellular pipe is filled with cytoplasm (for simplicity: homogeneous liquid). The resistance to local lateral deformation consists of 1. the turgor pressure (internal pressure of a living cell), 2. the cell wall (thickness ca. 100-200 nm).
Hypothetical case: The plasticity and thickness of the cell wall is identical at the apex and the remaining part of the cell. How can I calculate the force I would need to locally deform the apical part of the cell (i.e. cylindrical part directly adjacent to the half-sphere), compared to the more distal part (i.e. the purely cylindrical part further down the pipe). A ratio would be good enough (just to know, whether the apical, dome-shaped part would be stiffer or not)!
One more detail: local indentation of the cylindrical part under pressure needs about 20 times the force compared to indentation of the cylindrical empty tube, i.e. the wall only, without pressure.
Any kind of input, also reference to basic engineering literature (textbook? web site?) would be VERY welcome!!
PS: Any substantial calculations and ideas that would make their way into the scientific paper I am trying to write, will be honored with co-authorship!