Predicting Guar Seed Splitting by Compression between Two Plates Using Hertz Theory of Contact Stresses
Article first published online: 17 AUG 2012
© 2012 Institute of Food Technologists®
Journal of Food Science
Volume 77, Issue 9, pages E231–E239, September 2012
How to Cite
Vishwakarma, R. K., Shivhare, U. S. and Nanda, S. K. (2012), Predicting Guar Seed Splitting by Compression between Two Plates Using Hertz Theory of Contact Stresses. Journal of Food Science, 77: E231–E239. doi: 10.1111/j.1750-3841.2012.02861.x
- Issue published online: 7 SEP 2012
- Article first published online: 17 AUG 2012
- MS 20120152 Submitted 1/31/2012, Accepted 6/8/2012.
- apparent modulus of elasticity;
- contact stress;
- Guar seed;
- Hertz theory;
- mechanical properties;
Abstract: Hertz's theory of contact stresses was applied to predict the splitting of guar seeds during uni-axial compressive loading between 2 rigid parallel plates. The apparent modulus of elasticity of guar seeds varied between 296.18 and 116.19 MPa when force was applied normal to hilum joint (horizontal position), whereas it varied between 171.86 and 54.18 MPa when force was applied in the direction of hilum joint (vertical position) with in moisture content range of 5.16% to 15.28% (d.b.). At higher moisture contents, the seeds yielded after considerable deformation, thus showing ductile nature. Distribution of stresses below the point of contact were plotted to predict the location of critical point, which was found at 0.44 to 0.64 mm and 0.37 to 0.53 mm below the contact point in vertical and horizontal loading, respectively, depending upon moisture content. The separation of cotyledons from each other initiated before yielding of cotyledons and thus splitting of seed took place. The relationships between apparent modulus of elasticity, principal stresses with moisture content were described using second-order polynomial equations and validated experimentally.
Practical Application: Manufacture of guar gum powder requires dehulling and splitting of guar seeds. This article describes splitting behavior of guar seeds under compressive loading. Results of this study may be used for design of dehulling and splitting systems of guar seeds.