material elastic [
	 name = aggregate
	 rho = 2.7e-9   # density
	 E   = 40000	# young's modulus
	 nu  = 0.0	# poisson's ratio
]

material cohesive_linear [
	 name = cohesive
	 beta = 1
	 G_c = 60e-3
         penalty = 1000000
         sigma_c = 10
]