How strong is spider silk? Spider silk is pretty darn strong and all sorts of comparisons are made to steel. I'm more curious about the various moduli of spider silk and how it compares to other materials. What is the Young's modulus of spider silk? What is the bulk modulus of spider silk? What is the shear modulus of spider silk? In general how do those moduli describe the material properties of spider. A simpler way to ask the question, what does it mean when it is said that spider silk is strong?

Wikipedia has a remarkably well-cited article on the subject of silks and their various biological isoforms and mechanical properties. With respect to tensile strength, spider's silk is as tough as high-grade steel.

Explcitly, dragline silk was measured by Pérez-Rigueiro _at al._ to be 600 ± 50 MPa with a comparison to silkworm silk.

Reference:

* **Pérez-Rigueiro J, Elices M, Llorca J, Viney C**. 2001. Tensile properties ofArgiope trifasciata drag line silk obtained from the spider’s web. Journal of Applied Polymer Science 82: 2245–2251 [pdf]