Multidisciplinary design optimization is a fancy way of saying that a bunch of different people with different skills work together to make something really awesome.
Think about making a sandcastle at the beach. You might need someone to help dig the moat, someone to help you pile up the sand, someone to help decorate with seashells, and someone to help fill the moat with water. Each person is doing their own job, but together, they make an awesome sandcastle.
In a similar way, multidisciplinary design optimization means that lots of different experts work together to make a really good product. Maybe you need people who are good at designing the shape of something, people who can predict how it will perform, people who can figure out how to make it strong, people who can make it work with other things, and people who can test it to make sure it's safe.
Together, all of these people work together to design something that is not only cool, but also works really well. It's like a real-life example of the saying "two heads are better than one," except it's more like 100 heads working together!