Table 1.

Constitutive Models for Gram-Negative Envelope

Part	Material Model	Parameter	Selection			Estimate	Reference
			Soft	Intermediate	Stiff
Outer membrane	isotropic neo-Hookean	C10	1.61 MPa	4.83 MPa	8.05 MPa	KA = 50–250 mN/m	(33,41, 42, 43)
		D1	0.018 MPa−1	0.006 MPa−1	0.004 MPa−1	vOM = 0.485	(44)
		tOM	4 nm (2 nm per leaflet)			3–5 nm	(43,45)
Cell wall	orthotropic elastic	E1 (=EG)	25 MPa	50 MPa	75 MPa	25–75 MPa	(46, 47, 48)
		E2, E3 (=EP)	10 MPa	20 MPa	30 MPa	10–30 MPa	(48, 49, 50)
		v12, v13,v23, v32 (=vGP)	0.35			0.32–0.67	(47,51)
		v21, v31 (=vPG)	0.14			0.01–0.23	(47,51)
		G12, G13 (=GGP)	5.3 MPa	10.5 MPa	15.8 MPa	3.55–17.95 MPa	(Supporting Materials and Methods, Section A)
		G23 (=GP)	3.7 MPa	7.4 MPa	11.1 MPa	3.7–11.1 MPa
		tCW	4 nm			2–6 nm	(46,50,52)