*Article* **Numerical and Experimental Analysis of Torsion Springs Using NURBS Curves**

#### **Young Shin Kim 1, Yu Jun Song 2 and Euy Sik Jeon 3,\***


Received: 28 March 2020; Accepted: 7 April 2020; Published: 10 April 2020

**Abstract:** Torsion springs, which transfer power through the twisting of their coil, provide advantages such as module simplification and e fficient use of space. The design of a torsion spring has been formulated, but it is di fficult to determine the local behaviors of torsion springs according to actual load conditions. This study proposes a torsion-spring design method through finite element analysis (FEA) using nonuniform-rational-basis-spline (NURBS) curves. Through experimentation, the angle and displacement values for the actual spring load were converted into useable data. Torsion-spring displacement values were obtained via experimentation and converted into coordinates that may be expressed using NURBS curves. The results of these experiments were then compared to those obtained via FEA, and the validity of this method was thereby verified.

**Keywords:** torsion springs; FEA; NURBS; applied load; local behaviors
