Hosting CEED students for research projects on liquid crystal elastomers (Sept-Dec, 2022)  

    In 2022 Fall, we took part in Center for Excellence in Engineering and Diversity (CEED) at UCLA and welcomed three undergraduate students, Joy Uchegbu, Maritza Fuentes, and Ruth Reyes to work in our lab. The students are trained to measure the local strain field under uniaxial tension via the digital image correlation (DIC) method. Chen Wei, as a graduate research mentor, guided students through the process of preparing materials, experimental tests, and data post-process. 

The students first learned the basic background and fabrication of liquid crystal elastomers (LCEs), a special soft material combing the ordinary rubber network, and rod-like liquid crystals (LCs). Then they learned to uniaxial stretch the specimen with an Instron universal machine. After they got familiar with the mechanism of LCEs as well as how to post-process stress-strain curves, they applied the DIC method to measure the local strain. They learned to spray ink on the samples, track the speckles during stretching, and plot the strain components after processing the data. Finally, students reviewed the results of stress-strain curves, and strain components, getting a better understanding of LCEs.  

This experience inspires the interest of students in researching and provides them skills beneficial for further study.  

Photo taken at the lab (from left to right: Lihua Jin, Maritza Fuentes, Joy Uchegbu, and Ruth Reyes)

(a) Polydomain (left) and monodomain (right) LCEs. (b) The specimen sprayed with ink ready for DIC test. (c) Setup for DIC measurement.

Panel discussion with girls from Linda Marquez High School (Feb, 2020) 

Hosting CEED students for research projects on soft robotics (Sept-Dec, 2018) 

    In 2018 Fall, we partnered with Center for Excellence in Engineering and Diversity (CEED) at UCLA and hosted six freshmen to work on a research project, as a part of their class ENGR 87 Introduction to Engineering Disciplines. The six freshmen are: Emmanuel Boitey, Mya Cross, Rebecca Cielo Cruz, Susana Rastelli, Jasmine Raya, and Sarah Sleboda. They were assigned to build pneumatically-actuated soft actuators that can achieve both bending and twisting motions. Yuzhen, as a graduate research mentor, supervised them through the process of creating and testing a soft actuator.

    These students went through the whole procedure of building a soft actuator, including design, fabrication, control and testing. They learned to create a solid model for the molds in CAD, and to print their designs using 3D printers. After they got familiar with the silicone casting process, the students molded component parts and assembled them together. Meanwhile, they learned how to fix the broken parts and seal the intersections. They also built a control system that can adjust the pressure inside the air chambers. The control system contains an air pump, a voltage regulator and two solenoid valves. Finally, they tested the actuators with a multimeter, and showed how their actuators could be utilized to grasp various objects.

    This project provides the students a brief overview on designing soft actuators, as well as some hands-on activities. It would inspire these freshmen’s interest in soft robotics and encourage them to pursue a career in engineering.

Photo taken at the lab (from left to right: Jasmine Raya, Susana Rastelli, Sarah Sleboda, Cielo Cruz, Mya Cross, Emmanuel Boitey, Lihua Jin, Yuzhen Chen)

Yuzhen is demonstrating how to test the soft actuators

(a). 3D-printed molds used for casting the soft actuators, (b). Electro-pneumatic circuit for inflating and deflating a soft actuator, which contains an air pump, a voltage regulator and two solenoid valves (not included in this photo). The shape of a soft actuator (c) before and (d) after actuation. (e). A soft actuator twining around a marker.