Determining Modulus of Elasticity in Agricultural Products by Handy Spring Loaded Type Hardnessmeter

Abstract

A handy spring loaded type hardnessmeter with hemispherical die was used for measuring Young's modulus of elasticity of fruits and vegetables.
The measuring principle is based on the Hertz's theory dealing with the contact of two bodies, and Hooke's law for the spring.
The hardness or the compressive force was calculated in E/(1-μ²) theoretically, and the results were grphically represented.
The hardnesses of onions, taroes, radishes, carrots, kakis and apples were measured, and the values of E/(1-μ²) were calculated from the hardnesses, using the hardness vs. E/(1-μ²) curve.
The Young's modulus may be calculated, if the Poisson's ratio is determined.