Jay Sim

I’ve always loved working with my hands. As a kid I played with building toys like Lego and K'NEX and got a kick out of seeing how many shapes I could create. After taking some engineering classes in high school, it clicked that it was the right field for me because, with mechanical engineering specifically, the field is so broad that it allows me to incorporate that sense of play I love into myriad real-world constructions and to improve people’s lives with what I made.

I knew I wanted to join Stanford’s mechanical engineering program after a campus visit showed me how tight-knit the department was. Being part of a smaller group, especially at a school that places as much emphasis on and pours as many resources into graduate education as Stanford does, was a huge draw. I’m now in the third year of my PhD and I’m happy to report I know most of the faces in my cohort. 

I used to work in a 3D printing lab and have long had an interest in manufacturing advanced materials, so when I visited Professor Renee Zhao’s Soft Intelligent Materials Laboratory and saw their ongoing projects, I knew I wanted to join. We’re a device-driven lab, which naturally requires us to tinker more. I spend 70% of my time just tinkering with my hands and investigating how different stimuli – like heat, magnetic fields, and mechanical loads – affect functional or soft materials, which all have unique properties and are the base components for many innovative technologies. The other 30% of the time I try to replicate my findings using simulations so that the work also has some grounding. 

The lab works on a number of leading-edge material projects, like a biomedical device called the milli-spinner that uses compression to alter the microstructure of blood clots and shrink them safely and effectively. But I have to say I’m most passionate about my dissertation topic: material programming. Computer coding, as we know, is made of bits with zeros and ones, but if we consider our functional material as our bit, we can basically start to replicate what I like to call mechanical computing. I’m looking at whether or not I can selectively program material to perform a very fine-tuned response, much like programmed code. 

Professor Zhao knows that I plan to pursue a career outside academia, so in addition to working on my own research, she encourages me to have a hand in everything happening in the lab. I’ve learned a lot from her mentorship, and now as a teaching assistant, I get to mentor my own students. I’ve found that teaching helps me with my own mastery of fundamental concepts. Whenever you’re trying to learn something, the best way to test yourself on whether you truly understand it or not is to make sure that you’re able to teach it effectively to others. That’s a philosophy I developed after years of teaching a class on soft composites and soft robotics, in which we have students do finite element analysis using the software Abaqus, which is known – both in academia and in the industry – for having a notoriously high learning curve. Almost every time you run simulations on it, some kind of error pops up. When I first taught this class in my second year, there were a lot of errors that I didn’t know how to troubleshoot, but now it’s easy for me to look at a student’s computer, note their error, and immediately know how to help them. 

I still remember the teaching evaluations I get every quarter, and a positive note will stick with me for a while. I’m really happy with the progress I’ve made as a teaching assistant, so it was an honor to be recognized with a 2025 Centennial Teaching Assistant Award. 

I feel really good about my doctoral life because I’m passionate about my research and, because I spend so much time in the lab, my labmates and I have grown so close that we even enjoy grocery shopping together. I also love to play tennis, which I’ve been playing since I was 10. At Stanford, the court reservation system is competitive, so you have to be quick about booking your slot. I’ve seen the schedule fill up for the week within minutes! I’m happy to hold a racket once a week because that’s one of my favorite ways to unwind.