Stress, Strain-Rate Analysis of Sub-Surface Driveway Plants

Abstract

Sub-surface driveway plants are strong enough to penetrate a macadam surface of thickness 7 -9 cm. The mechanics of how the Taraxacum officinale accomplishes this feat remain a mystery. Using the Maxwell model for pavement yielding over time, data are presented which may shed some light on this phenomenon. The post-buckling behavior of the plant stalk is quantified. Euler bending and buckling theory enables calculation of the cellular stress field, compared to turgor pressure, indicating impending cell buckling. Post-buckling plastic strain of the plant stem is 19%. At the cell wall, the stress concentration factor is 3-times greater than the applied external field, so the cell's internal turgor pressure is overwhelmed by imposed external stress. An Impulse Integral is developed for the surface whereby the product of applied FORCE times TIME is CONSTANT, in order to produce a given amount of surface deflection. Taraxacum officinale stems and leaf stalks are strong enough, in buckling mode, to lift and push apart the fractured macadam crater through which they erupt, but not strong enough to initially crack the surface. The purpose of this work is to determine the mechanisms underlying this unusual plant survival phenomenon, backed by quantified data.

Narcissus (Daffodil) Phototropism, Applications to Alzheimer's Drug Development

“…In the mechanical domain, mechanosensing (Greene et al(2015(Greene et al( , 2017) is a phenomenon whereby the stalks react, growing stronger (or weaker) in response to stress, strain, and buckling loads imposed by the environment, typically wind and rain driven forces. In this instance for the daffodil, mechanosensing is possibly a matter of arresting or slowing growth, because buckling causes "crimping" of the stems when the plant is collapsed to the ground, as happens several times during April showers.…”

Scaling Laws for Vascular Buckling, Axial and Circumferential: Applications to Pulse Wave Velocity

“…Greene and Greene [14] present experimental buckling data for tubes of radius 0.25 " (6 mm) , lengths 1" to 6" (2.5 to 15 cm) during axial buckling, yielding Young's moduli in compression of 3 to 14 MPa for Taraxacum and 1600 to 1700 MPa for Hypochaeris plant tubes in vitro. These stem and leaf tubes are inflated in vivo to 1 atmosphere [15][16][17][18][19][20].…”

Statistical Distribution Functions for Daffodil Plants – Directions & Numbers

“…f (x) dx = A exp ( -a x )dx = 0.12 exp ( -0.1 x ) dx [1] where A = 0.12 and a = 0.1 Example 1 -As an example of how such a function is used, as a practical matter, say that you want to calculate the % percentage of plants that fall in the range of1 to 10 flowers per plant. This then is simply a matter of evaluating the integral over the limits x = 1 to x = 10: In words, this simply means that 93% percent of the daffodil plants will yield from 1 to 20 flowers per plant.…”