diff --git a/src/ComputationalModels/EvolutionFunctions.jl b/src/ComputationalModels/EvolutionFunctions.jl
index e77e2e6..1f82e91 100644
--- a/src/ComputationalModels/EvolutionFunctions.jl
+++ b/src/ComputationalModels/EvolutionFunctions.jl
@@ -1,4 +1,17 @@
 
+"The evolution functions have been designed to apply variable boundary conditions."
+module EvolutionFunctions
+
+export ramp
+export triangular
+export step
+export sigmoid
+export constant
+
+"Return an unbounded ramp function. By default, it is the identity. Otherwise, the scaling factor is 1/T."
+function ramp(T::Float64=1.0)
+  t::Float64 -> t/T
+end
 
 "Return a triangular evolution function ranging from 0 to 1, centered at T, having edges at 0 and 2T."
 function triangular(T::Float64)
@@ -40,3 +53,5 @@ end
 function constant()
   t::Float64 -> 1.0
 end
+
+end
diff --git a/test/data/StaticMechanicalDirichletSimulation.jl b/test/data/StaticMechanicalDirichletSimulation.jl
index 1bb0688..38627b5 100644
--- a/test/data/StaticMechanicalDirichletSimulation.jl
+++ b/test/data/StaticMechanicalDirichletSimulation.jl
@@ -5,6 +5,7 @@ using TimerOutputs
 using Gridap.FESpaces
 using HyperFEM
 using HyperFEM.ComputationalModels.CartesianTags
+using HyperFEM.ComputationalModels.EvolutionFunctions
 
 
 function static_mechanical_dirichlet_simulation(;writevtk=true, verbose=true)
@@ -32,7 +33,7 @@ function static_mechanical_dirichlet_simulation(;writevtk=true, verbose=true)
   # Dirichlet boundary conditions
   dir_u_tags = ["fixed", "moving"]
   dir_u_values = [[0.0, 0.0, 0.0], [0.08, 0.0, 0.0]]
-  dir_u_timesteps = [Λ -> 1.0, Λ -> Λ]
+  dir_u_timesteps = [constant(), ramp()]
   D_bc = DirichletBC(dir_u_tags, dir_u_values, dir_u_timesteps)
 
   #  FE spaces
diff --git a/test/data/StaticMechanicalNeumannSimulation.jl b/test/data/StaticMechanicalNeumannSimulation.jl
index 718863c..5bd25e3 100644
--- a/test/data/StaticMechanicalNeumannSimulation.jl
+++ b/test/data/StaticMechanicalNeumannSimulation.jl
@@ -5,6 +5,7 @@ using TimerOutputs
 using Gridap.FESpaces
 using HyperFEM
 using HyperFEM.ComputationalModels.CartesianTags
+using HyperFEM.ComputationalModels.EvolutionFunctions
 
 
 function static_mechanical_neumann_simulation(;writevtk=true, verbose=true)
@@ -32,13 +33,13 @@ function static_mechanical_neumann_simulation(;writevtk=true, verbose=true)
   # Dirichlet conditions 
   dir_u_tags = ["fixed"]
   dir_u_values = [[0.0, 0.0, 0.0]]
-  dir_u_timesteps = [Λ -> 1.0]
+  dir_u_timesteps = [constant()]
   D_bc = DirichletBC(dir_u_tags, dir_u_values, dir_u_timesteps)
 
   # Neumann conditions 
   neu_F_tags = ["force"]
   neu_F_values = [[0.0, 0.0, -1e-3]]
-  neu_F_timesteps = [Λ -> Λ]
+  neu_F_timesteps = [ramp()]
   N_bc = NeumannBC(neu_F_tags, neu_F_values, neu_F_timesteps)
   dΓ = get_Neumann_dΓ(geometry, N_bc, degree)
 
diff --git a/test/data/ViscoElasticSimulation.jl b/test/data/ViscoElasticSimulation.jl
index 73b07f7..a5ba220 100644
--- a/test/data/ViscoElasticSimulation.jl
+++ b/test/data/ViscoElasticSimulation.jl
@@ -4,8 +4,7 @@ using GridapSolvers
 using GridapSolvers.NonlinearSolvers
 using HyperFEM
 using HyperFEM.ComputationalModels.CartesianTags
-using HyperFEM.ComputationalModels:constant
-using HyperFEM.ComputationalModels:triangular
+using HyperFEM.ComputationalModels.EvolutionFunctions
 using HyperFEM.ComputationalModels.PostMetrics
 
 function visco_elastic_simulation(;t_end=15, writevtk=true, verbose=true)