2016-06-19 20:01:37 +03:00
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# This file is a part of JuliaFEM.
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# License is MIT: see https://github.com/JuliaFEM/JuliaFEM.jl/blob/master/LICENSE.md
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2018-09-06 12:08:16 +03:00
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using JuliaFEM, Test
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# Test stiffness matrix of geometrically nonlinear problem
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X = Dict(1 => [0.0, 0.0], 2 => [1.0, 0.0], 3 => [1.0, 1.0], 4 => [0.0, 1.0])
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u = Dict(1 => [0.1, 0.2], 2 => [0.3, 0.4], 3 => [0.5, 0.6], 4 => [0.7, 0.8])
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T = Dict(3 => [0.0, 288.0], 4 => [0.0, 288.0])
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element = Element(Quad4, (1, 2, 3, 4))
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update!(element, "geometry", X)
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update!(element, "displacement", u)
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update!(element, "youngs modulus", 288.0)
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update!(element, "poissons ratio", 1/3)
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2016-06-19 20:01:37 +03:00
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2018-09-06 12:08:16 +03:00
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traction = Element(Seg2, (3, 4))
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update!(traction, "geometry", X)
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update!(traction, "displacement", u)
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update!(traction, "displacement traction force", T)
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# field problem
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block = Problem(Elasticity, "block", 2)
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block.properties.formulation = :plane_stress
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block.properties.finite_strain = true
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block.properties.geometric_stiffness = true
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add_element!(block, element)
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#add_elements!(block, traction)
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assemble!(block, 0.0)
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Km = Matrix(block.assembly.K)
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Kg = Matrix(block.assembly.Kg)
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K = Km + Kg
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f = Vector(block.assembly.f)
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K_expected = [
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401.76 200.88 -123.12 -5.76 -191.52 -117.36 -87.12 -77.76
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200.88 473.76 -5.76 28.08 -117.36 -205.92 -77.76 -295.92
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-123.12 -5.76 197.28 -2.16 -12.24 -25.92 -61.92 33.84
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-5.76 28.08 -2.16 298.08 -25.92 -163.44 33.84 -162.72
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-191.52 -117.36 -12.24 -25.92 240.48 120.24 -36.72 23.04
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-117.36 -205.92 -25.92 -163.44 120.24 312.48 23.04 56.88
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-87.12 -77.76 -61.92 33.84 -36.72 23.04 185.76 20.88
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-77.76 -295.92 33.84 -162.72 23.04 56.88 20.88 401.76]
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# f_expected = [142.272, 214.272, -13.824, 58.176, -75.456, 19.584, -52.992, -4.032]
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f_expected = [142.272, 214.272, -13.824, 58.176, -75.456, -124.416, -52.992, -148.032]
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@test isapprox(K, K_expected)
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@test isapprox(f, f_expected)
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