Scientists crack the code on plastic deformation, opening door to tougher materials
Researchers have developed the first comprehensive model that accurately predicts how high-density polyethylene behaves under stress over time — a capability that could transform how manufacturers design plastic products and components. The breakthrough enables engineers to build more durable, reliable plastics by simulating real-world conditions before production, potentially reducing costly failures and extending product lifespans.
Originaltitel: Experimental and theoretical study of stress relaxation in high-density polyethylene
<p>Stress relaxation of high-density polyethylene is addressed both experimentally and theoretically. Two types of stress relaxation testing are carried out: uniaxial tensile testing at constant test specimen length and compression testing of a 3D structure producing inhomogeneous deformation fields and relaxation. A constitutive model for isotropic, semi-crystalline polymers is also proposed. The model has the ability to model stress relaxation at different time scales. The developed model was implemented as a user subroutine in Abaqus (UMAT). The implicit integration scheme including an algorithmic tangent modulus is described in detail. The material model is calibrated by use of the uniaxial tensile tests, and the model is then validated by simulating the compression tests of the 3D structure. The model is able to describe the uniaxial tension tests well, and the comparison between the simulations and experimental testing of the 3D structure shows very good agreement.</p>