D18 vs D80

D80 is 2.5 times as stiff as D18. It is about twice as dense. Per unit mass D80 is 1.3 times as stiff. Strength: f_m,k = 18 MPa for D18, f_m,k = 80 MPa for D80.

D18 EN 338:2016 D80 EN 338:2016

Side by side

ratio = D80 / D18 · log scale

Property	D18	D80	Unit	Ratio
E₁ Modulus, direction 1	9.5	24	GPa	2.53×
E₂ Modulus, direction 2	0.63	1.6	GPa	2.54×
E₃ Modulus, direction 3	0.63	1.6	GPa	2.54×
G₁₂ Shear modulus 1-2	0.59	1.5	GPa	2.54×
G₁₃ Shear modulus 1-3	0.59	1.5	GPa	2.54×
E₀,₀₅ Modulus parallel to grain, 5 % fractile	8	20.2	GPa	2.52×
ρ Density	570	1080	kg/m³	1.89×
ρ_k Density, characteristic (5 % fractile)	475	900	kg/m³	1.89×
f_m,k Bending strength	18	80	MPa	4.44×
f_t,0,k Tension parallel to grain	11	48	MPa	4.36×
f_t,90,k Tension perpendicular to grain	0.6	0.6	MPa	1×
f_c,0,k Compression parallel to grain	18	38	MPa	2.11×
f_c,90,k Compression perpendicular to grain	4.8	13.5	MPa	2.81×
f_v,k Shear strength	3.5	5	MPa	1.43×
E/ρ Specific stiffness E/ρ · derived	16.67	22.22	MJ/kg	1.33×
c₀ Bar wave speed √(E/ρ) · derived	4082	4714	m/s	1.15×
f/ρ Specific strength f/ρ · derived	31.58	74.07	kJ/kg	2.35×

Values at the first thickness band or product form of each material (EN 338:2016; EN 338:2016). A minimum and a characteristic value are not the same kind of number — read the ratio as a guide. Each material's page lists every band and every source.