D70 vs D80

D80 is 1.2 times as stiff as D70. It is 1.1 times as dense. Per unit mass they are about equally stiff (20.83 and 22.22 MJ/kg). Strength: f_m,k = 70 MPa for D70, f_m,k = 80 MPa for D80.

D70 EN 338:2016 D80 EN 338:2016

Side by side

ratio = D80 / D70 · log scale

Property	D70	D80	Unit	Ratio
E₁ Modulus, direction 1	20	24	GPa	1.2×
E₂ Modulus, direction 2	1.33	1.6	GPa	1.2×
E₃ Modulus, direction 3	1.33	1.6	GPa	1.2×
G₁₂ Shear modulus 1-2	1.25	1.5	GPa	1.2×
G₁₃ Shear modulus 1-3	1.25	1.5	GPa	1.2×
E₀,₀₅ Modulus parallel to grain, 5 % fractile	16.8	20.2	GPa	1.2×
ρ Density	960	1080	kg/m³	1.12×
ρ_k Density, characteristic (5 % fractile)	800	900	kg/m³	1.12×
f_m,k Bending strength	70	80	MPa	1.14×
f_t,0,k Tension parallel to grain	42	48	MPa	1.14×
f_t,90,k Tension perpendicular to grain	0.6	0.6	MPa	1×
f_c,0,k Compression parallel to grain	36	38	MPa	1.06×
f_c,90,k Compression perpendicular to grain	12	13.5	MPa	1.12×
f_v,k Shear strength	5	5	MPa	1×
E/ρ Specific stiffness E/ρ · derived	20.83	22.22	MJ/kg	1.07×
c₀ Bar wave speed √(E/ρ) · derived	4564	4714	m/s	1.03×
f/ρ Specific strength f/ρ · derived	72.92	74.07	kJ/kg	1.02×

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.