Poisson’s Ratio and Shear Stresses
Warning: if you’re not a Mechanical, Matieral, or Civil engineer this might make absolutely no sense because I’m going to talk as if you have prior knowledge of the two concepts in the post title. Sorry. I had an epiphany.
So, I’m a Civil engineering grad student and one class I’m taking this semester is on composite materials, specifically fibrous materials (like fiber glass and such). Lately we’ve been studying single ply laminas (only one layer, with fibers running in only one direction) and how applying stresses at different angles creates different amounts of strain. Just like BIAS FABRIC.
Bam. Molly’s mind = Blown.
Fabric cut on the bias or sewn on the bias is reacting to a shear stress (pulling) applied to it, causing it to strain (or stretch) and due to Poisson’s ratio at a 45 degree angle the fabric will contract in the perpendicular off-axis direction (or perpendicular to the true bias)!
You have no idea how excited I was when I thought of this. And again, I’m sorry if you didn’t understand a word I just said, I just really had to get it out of my system because none of the guys at school would have known what bias cut fabric is… It’s like I live in two completely different worlds.