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chore(legacy): remove orphaned truss Problem implementation
Delete the Dict-field truss assembler that remained disconnected from the `Legacy` entry module. - Drop `src/legacy/problems_truss.jl`.
This commit is contained in:
Jukka Aho
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# This file is a part of JuliaFEM.
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# License is MIT: see https://github.com/JuliaFEM/FEMTruss.jl/blob/master/LICENSE
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""" Truss implementation for JuliaFEM. """
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# Truss element - consolidated from FEMTruss.jl
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get_unknown_field_name,
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get_formulation_type,
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assemble!
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"""
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This truss fromulation is from
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Concepts and applications of finite element analysis, forth edition
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Chapter 2.4
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Cook, Malkus, Plesha, Witt
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# Features
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- Nodal forces can be set using element `Poi1` with field
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`nodal force i`, where `i` is dof number.
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- Displacements can be fixed using element `Poi1` with field
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`fixed displacement i`, where `i` is dof number.
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- Temperature loads can be set by setting field `thermal expansion coefficient`
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and field `temperature difference`
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"""
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mutable struct Truss <: FieldProblem
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end
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function get_unknown_field_name(::Problem{Truss})
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return "displacement"
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end
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function get_formulation_type(::Problem{Truss})
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return :total
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end
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"""
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get_truss_1d_and_Tg(element::Element{M,Seg2})
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This function sets up the local truss 1d element needed for
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the integration points to be used for the stiffness and forces
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It also sets up the coordinate transformation matrix
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Will need to change allocation strategy to pre-allocation later
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"""
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function get_truss_1d_and_Tg(element::Element{M,Seg2}, ndim) where M
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node_id1 = element.connectivity[1] #First node in element
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node_id2 = element.connectivity[2] #second node in elements
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pos = element("geometry")
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dl = pos[node_id2] - pos[node_id1]
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l = sqrt(dot(dl, dl))
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# Do the local element for calculations
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elem_1d = Element(Seg2, [1, 2])
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elem_1d.id = -1 # To signal it is local
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X = Dict{Int64,Vector{Float64}}(
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1 => [0.0],
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2 => [l])
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update!(elem_1d, "geometry", X)
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if ndim == 1
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T = eye(Float64, 2)
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elseif ndim == 2
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l_theta = dl[1] / l
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m_theta = dl[2] / l
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T = [l_theta m_theta 0 0; 0 0 l_theta m_theta]
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else # All three dimensions
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l_theta = dl[1] / l
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m_theta = dl[2] / l
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n_theta = dl[3] / l
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T = [l_theta m_theta n_theta 0 0 0; 0 0 0 l_theta m_theta n_theta]
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end
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return (elem_1d, T)
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end
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"""
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get_truss_1d_K(element::Element{M,Seg2}, nnodes, time)
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This function assembles the 1d truss stiffness matrix
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Will need to change allocation strategy to pre-allocation later
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Can discuss if we really need nnodes, since that is always 2 for trusses
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"""
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function get_truss_1d_K(elem_1d::Element{M,Seg2}, nnodes, time) where M
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K_loc = zeros(nnodes, nnodes)
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for ip in get_integration_points(elem_1d)
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dN = elem_1d(ip, time, Val{:Grad})
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detJ = elem_1d(ip, time, Val{:detJ})
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A = elem_1d("cross section area", ip, time)
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E = elem_1d("youngs modulus", ip, time)
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K_loc += ip.weight * E * A * dN' * dN * detJ
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end
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return K_loc
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end
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"""
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has_temperature_load(elem_1d::Element{M,Seg2})
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checks if we have a temperature load on the truss element
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"""
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function has_temperature_load(elem_1d::Element{M,Seg2}) where M
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return haskey(elem_1d, "temperature difference") && haskey(elem_1d, "thermal expansion coefficient")
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end
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"""
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get_truss_1d_f(element::Element{M,Seg2}, nnodes, time)
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This function assembles the 1d truss force vector
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Will need to change allocation strategy to pre-allocation later
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Can discuss if we really need nnodes, since that is always 2 for trusses
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"""
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function get_truss_1d_f(elem_1d::Element{M,Seg2}, nnodes, time) where M
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fe = zeros(nnodes)
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if has_temperature_load(elem_1d)
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for ip in get_integration_points(elem_1d)
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dt = elem_1d("temperature difference", ip, time)
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lambda = elem_1d("thermal expansion coefficient", ip, time)
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A = elem_1d("cross section area", ip, time)
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E = elem_1d("youngs modulus", ip, time)
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N = elem_1d(ip, time)
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detJ = elem_1d(ip, time, Val{:detJ})
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f = E * A * lambda * dt
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fe += ip.weight * N' * f # *detJ
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end
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fe[end] *= -1.0
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end
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# how do we generally set the right sides negative
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return fe
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end
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"""
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get_Kg_and_Tg(element::Element{M,Seg2}, nnodes, ndim, time)
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This function assembles the local stiffness uses global transformation matrix
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to make the global version of the local stiffnes matrix
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Will need to change allocation strategy to pre-allocation later
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Can discuss if we really need nnodes, since that is always 2 for trusses
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"""
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function get_Kg_and_Tg(element::Element{M,Seg2}, nnodes, ndim, time) where M
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elem_1d, T = get_truss_1d_and_Tg(element, ndim)
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# Update props for stiffness attributes
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update!(elem_1d, "youngs modulus", element("youngs modulus"))
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update!(elem_1d, "cross section area", element("cross section area"))
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K_loc = get_truss_1d_K(elem_1d, nnodes, time)
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ndofs = nnodes * ndim
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K = zeros(ndofs, ndofs)
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K = T' * K_loc * T
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return (K, T)
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end
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function get_F_local(element::Element{M,Seg2}, nnodes, ndim, time) where M
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elem_1d, T = get_truss_1d_and_Tg(element, ndim)
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# Update props for stiffness attributes
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update!(elem_1d, "youngs modulus", element("youngs modulus"))
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update!(elem_1d, "cross section area", element("cross section area"))
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if (has_temperature_load(element))
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update!(elem_1d, "thermal expansion coefficient", element("thermal expansion coefficient"))
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update!(elem_1d, "temperature difference", element("temperature difference"))
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end
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f = get_truss_1d_f(elem_1d, nnodes, time)
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return f
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end
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"""
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assemble!(assembly:Assembly, problem::Problem{Elasticity}, elements, time)
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Start finite element assembly procedure for Elasticity problem.
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Function groups elements to arrays by their type and assembles one element type
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at time. This makes it possible to pre-allocate matrices common to same type
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of elements.
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"""
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function assemble!(assembly::Assembly, problem::Problem{Truss},
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element::Element{M,Seg2}, time) where M
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#Require that the number of nodes = 2 ?
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nnodes = length(element)
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ndim = get_unknown_field_dimension(problem)
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elem_1d, T = get_truss_1d_and_Tg(element, ndim)
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# setuo the things needed for local stiffness matrix
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update!(elem_1d, "youngs modulus", element("youngs modulus"))
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update!(elem_1d, "cross section area", element("cross section area"))
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K_loc = get_truss_1d_K(elem_1d, nnodes, time)
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ndofs = nnodes * ndim
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K = zeros(ndofs, ndofs)
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K = T' * K_loc * T
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gdofs = get_gdofs(problem, element)
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add!(assembly.K, gdofs, gdofs, K)
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if has_temperature_load(element)
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update!(elem_1d, "thermal expansion coefficient", element("thermal expansion coefficient"))
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update!(elem_1d, "temperature difference", element("temperature difference"))
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f = get_truss_1d_f(elem_1d, nnodes, time) * -1.0 #Needs to be negated
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fg = T' * f
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add!(assembly.f, gdofs, fg)
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end
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#add!(assembly.f, gdofs, f)
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end
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assemble_elements!
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function assemble_elements!(problem::Problem, assembly::Assembly,
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elements::Vector{Element{M,Poi1}}, time::Float64) where M
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dim = ndofs = get_unknown_field_dimension(problem)
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Ce = zeros(ndofs, ndofs)
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ge = zeros(ndofs)
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fe = zeros(ndofs)
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for element in elements
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fill!(Ce, 0.0)
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fill!(ge, 0.0)
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fill!(fe, 0.0)
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ip = (0.0,)
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for i = 1:dim
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if haskey(element, "fixed displacement $i")
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Ce[i, i] = 1.0
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ge[i] = element("fixed displacement $i", ip, time)
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end
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if haskey(element, "nodal force $i")
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fe[i] = element("nodal force $i", ip, time)
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end
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end
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gdofs = get_gdofs(problem, element)
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add!(assembly.C1, gdofs, gdofs, Ce)
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add!(assembly.C2, gdofs, gdofs, Ce)
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add!(assembly.g, gdofs, ge)
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add!(assembly.f, gdofs, fe)
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end
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end
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export Truss, get_Kg_and_Tg, get_F_local
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