Fiber-Reinforced Compliant Closed-Cell Joint Using Geodesic-Isotensoid Designs

Abstract

Compliant closed-cell joints do not buckle under compression and exhibit a higher axial-to-rotational stiffness ratio than conventional compliant joints by using a fluid encapsulated in a flexible cell as the main load-bearing element. However, the axial and shear stiffness are still insufficient to replace spherical or universal joints in high load-bearing applications. This thesis aims to address this by using a fiber-reinforced cell wall. To make optimal use of the fiber strength, adapted geodesic-isotensoid designs are proposed.
To evaluate the performance of different geodesic-isotensoid designs, an axial mathematical model was developed and validated with a finite element model. Furthermore, both models were used to evaluate the axial, rotational, and shear stiffness, as well as the load-bearing capacity of the joint across a range of designs. The results can be used to guide the design of future fiber-reinforced compliant closed-cell joints. Additionally, it was found that adding extra fibers increases axial stiffness without affecting rotational stiffness, enabling high axial-to-rotational stiffness ratios.