Predicting the Bending of 3D Printed Hyperelastic Polymer Components.

Area of Science:

• Materials Science
• Mechanical Engineering
• Additive Manufacturing

Background:

• 3D printing is widely used, with NinjaFlex® (thermoplastic polyurethane) being a popular flexible filament.
• The mechanical properties of 3D printed NinjaFlex® parts, particularly under bending, are not well-understood.
• Accurate prediction of flexible 3D printed part behavior is crucial for design and application.

Purpose of the Study:

• To predict the bending behavior of small 3D printed NinjaFlex® components.
• To compare experimental results with theoretical models and computational analysis.
• To assess the accuracy of the modified Euler-Bernoulli Beam Theorem (MEB) and finite element analysis (FEA) for flexible TPU parts.

Main Methods:

• 3D printing of rectangular NinjaFlex® specimens with varying dimensions.
• Loading specimens as cantilevers and measuring deflection using a computer.
• Comparing experimental deflection data with predictions from the modified Euler-Bernoulli Beam Theorem (MEB) and finite element analysis (FEA).

Main Results:

• Both MEB and FEA models demonstrated high accuracy in predicting the deflection of 3D printed NinjaFlex® specimens.
• Average differences between experimental data and MEB predictions ranged from 0.6% to 3.0%.
• Average differences between experimental data and FEA predictions ranged from 0.4% to 2.4%, with FEA showing higher retraction for highly flexible parts.

Conclusions:

• The modified Euler-Bernoulli Beam Theorem and finite element analysis are effective tools for predicting the mechanical behavior of 3D printed NinjaFlex® components.
• MEB slightly underestimated results for the most flexible specimens, while FEA generally provided accurate predictions.
• These findings support the use of computational and theoretical models in designing with flexible 3D printing materials.