Design and analysis of Outside-Deployed Lamina Emergent Joint (OD-LEJ)

Abstract

Lamina emergent mechanisms (LEMs) can be fabricated in plane, while achieve motion that emerges out of fabrication plane. This paper presents a new flexure hinge called Outside-Deployed Lamina Emergent Joint (OD-LEJ) with a small equivalent spring constant and a large angular displacement. The closed-form model is given and a finite element analysis (FEA) model is created. The FEA results show that this joint can achieve nearly 170.17˚ of rotation without plastic deformation. Stress analysis is done and the results gotten from theoretical calculation and FEA coincide with each other very well. Safety analysis and fatigue analysis are done as well. An Inside-Deployed Lamina Emergent Joint (ID-LEJ) is also proposed. The joint is analyzed through FEA and theoretical calculation. The joint shows a similar bending property as OD-LEJ. Comparisons between these two joints and Lamina Emergent Torsional (LET) joint are made. OD-LEJ and ID-LEJ do better than LET joint in large angular displacement and have a smaller equivalent spring constant. Finally, the movement of the center of rotation and some other problems are discussed.