Glossary (глосарій)

is the increase in length after fracture divided bу the initial length and multiplied bу 100 is the percentage elongation.

is a solid material composed of polymer molecules that has some structural rigidity under applied load; typically used in many general purpose applications (e.g., milk jugs, trash bags, disposable utensils, bike helmets).

is defined as the ratio of the strain in the lateral direction to that in the axial direction of bar 

is an organic compound of high molecular weight with a molecular structure composed of small repeating units (e.g., polyethylene is composed of repeat units of C2H4); polymer molecules are sometimes referred to as polymer “chains”, due to their predominantly linear physical dimensions.

are the axes, where we have the maximum and minimum values of moment of inertia for a given cross - section

are the moments of inertia, one of them has maximum and another of them has  minimum values for a given cross - section

 is given by the summation of the products of inertia about those same axes of all elements of area contained within the finite area