material elastic [
	 name = steel
	 rho = 1e3   # density
	 E   = 1e3   # young's modulus
	 nu  = 0.001 # poisson's ratio
]

material cohesive_linear [
	 name = cohesive
	 beta = 1
	 G_cI = 100
	 G_cII = 100
	 sigma_c = 100
	 volume_s = 1
]

material cohesive_linear [
	 name = cohesive2
	 beta = 1
	 G_cI = 100
	 G_cII = 100
	 sigma_c = 1000
]