Numerical Results for shear-lock free finite elements based on Mindlin-Reissner plate and Timoshenko beam theories Plate Elements NxN Mesh Size (Full Plate) Exact Solution Srinivasa Rao and AK Rao and Theory of Plates and Shells CF Convergence Factor ASR Aspect Ratio MR_FE_1 MR_FE_2 MR_FE_3 MR_FE_4 Finite Elements based on Mindlin-Reissner theory using new shape functions Material: E=1.092E06; 𝜐 = 0.3; Geometry: Square plate a=10.0; h=2.0, 1.4, 1.0, 0.5; Type of plate Simply supported (SS) Load: UDL=10.0 Timoshenko beam elements N Number of Elements (Full beam) Exact Solution Theory of Elasticity CF Convergence Factor ASR Aspect Ratio Timo_FE_1 Timo_FE_2 Timo_FE_3 Timo_FE_4 Finite Elements based on Timoshenko beam theory using new shape functions Material: 29,000; 𝜐 = 0.3; Geometry: L=5,10, 25,100, 200, 400; h=1.0; b=1.0; Load: Concentrated Load q=100.0 Higher order beam elements (capable of accurately predicting three dimensional stresses) based on the higher order shear deformation theories developed by me HFE_1 HFE_3 FE_NSF_1 FE_NSF_3 - based on Lagrangian polynomials based on Lagrangian polynomials based on new shape functions based on new shape functions Advantages of the present new finite elements 1. The primary aim of this research work is to replace the finite elements based on the first order shear deformation theory available in the general purpose finite element packages by these new finite elements. 2. Presently all general purpose finite element packages like MSC-NASTRAN, NX- NASTRAN, ABAQUS, LS-DYNA, and ANSYS use the finite elements based on Timoshenko beam theory, Reissner-Mindlin plate theory and Kirchhoff-Love shell theory ( all are called first order shear deformation theories). The drawback of these finite elements is that they can not be used for the analysis of thin structures due to shear lock problem. To eliminate this problem, special integration scheme must be used. The new finite elements based on the Timoshenko beam theory, Reissner-Mindlin Plate theory developed by me using special shape functions and standard finite element procedure are applied to the analysis of beams and plates. The numerical results show that accurate solution is obtained for less number of elements. The specialties of these finite elements are that (i) thick and thin structures can be analyzed, (ii) No special integration scheme is required, (iii) a new concept, Convergence Factor (CF), is introduced in the formulation of these elements to accelerate convergence, and (iv) Accurate solution is obtained by keeping the number of elements as constant and increasing the value of the CF. Hence, this procedure reduces modeling effort, computational time and increasing accuracy. 3. Arbitrary higher order continuity can be achieved in this development. This is very essential for the problems related to crack propagation where high stress gradient exists near the crack tip. 4. A comparison study was carried out among the finite elements based on the new shape functions and Lagrangian shape functions using two higher order shear deformation theories developed by me for the analysis of simply supported beam under transverse load. The convergence is achieved faster than that of the finite elements based on the Lagrangian shape functions. 5. Considering the above points, study related to the development of triangular finite elements based on the new shape functions is in progress. 6. Compare to the development of other thin plate finite elements like Discrete Kirchhoff Theory (DKT) finite element and Mixed Interpolated Tensorial Component (MITC4) element, the development of these finite elements is very simple. 7. Since these new shape functions are very effective in accurately predicting displacements, strains and stresses, finite elements based on these shape functions can be developed for various applications, for example, multiscale modelling, crack propagation and gradient-enhanced damage models. Simply supported plate with UDL for ASR = 5.0 error in deflection at centre 80.00 Aspect Ratio = 5 Mesh size = 2 x 2 30.00 -20.00 1.00 10.00 100.00 1,000.00 10,000.00 % Error Convergence Factor -70.00 Element 1 -120.00 Element 2 Element 3 -170.00 Element 4 -220.00 Fig.1 80.00 Aspect Ratio = 5 Mesh size = 4 x 4 60.00 40.00 20.00 0.00 % Error 1.00 -20.00 -40.00 10.00 100.00 Convergence Factor Element 1 -60.00 Element 2 -80.00 Element 3 -100.00 1,000.00 Element 4 -120.00 Fig.2 10,000.00 Aspect Ratio = 5 Mesh size = 6 x 6 65.00 45.00 25.00 % Error 5.00 -15.00 1.00 10.00 100.00 1,000.00 Convergence Factor 10,000.00 -35.00 Element 1 -55.00 Element 2 Element 3 -75.00 Element 4 -95.00 -115.00 Fig.3 80.00 Aspect Ratio = 5 Mesh size = 10 x 10 60.00 40.00 % Error 20.00 0.00 1.00 10.00 100.00 -20.00 -40.00 Convergence Factor Element 1 Element 2 -60.00 -80.00 1,000.00 Element 3 Element 4 -100.00 Fig.4 10,000.00 80.00 Aspect Ratio = 5 Mesh size = 14 x 14 60.00 40.00 % Error 20.00 0.00 1.00 10.00 100.00 -20.00 -40.00 -60.00 Convergence Factor Element 1 Element 3 Element 2 -80.00 1,000.00 Element 4 -100.00 Fig.5 10,000.00 Simply supported plate with UDL for ASR = 7.14 error in deflection at centre 75 Aspect Ratio = 7.14 Mesh size = 2 x 2 55 35 % Error 15 -5 1.00 10.00 100.00 1,000.00 10,000.00 Convergence Factor -25 Element 1 Element 2 -45 Element 3 -65 Element 4 -85 Fig.1 80 Aspect Ratio = 7.14 Mesh size = 4 x 4 Element 1 Element 2 60 Element 3 Element 4 % Error 40 20 0 1.00 10.00 100.00 1,000.00 Convergence Factor -20 -40 Fig.2 10,000.00 75 Aspect Ratio = 7.14 Mesh size = 6 x 6 Element 1 Element 2 55 Element 3 Element 4 35 % Error 15 -5 1.00 10.00 100.00 1,000.00 Convergence Factor 10,000.00 -25 -45 Fig.3 70 Aspect Ratio = 7.14 Mesh size = 10 x 10 Element 1 Element 2 Element 3 50 Element 4 % Error 30 10 -10 1.00 10.00 100.00 Convergence Factor -30 -50 Fig.4 1,000.00 10,000.00 70 Aspect Ratio = 7.14 Mesh size = 14 x 14 Element 1 Element 2 Element 3 50 Element 4 % Error 30 10 -10 1.00 10.00 100.00 Convergence Factor -30 -50 Fig.5 1,000.00 10,000.00 Simply supported plate with UDL for ASR =10.0 error in deflection at centre 70 Aspect Ratio = 10.0 Mesh size = 2 x 2 Element 1 Element 2 50 Element 3 Element 4 % Error 30 10 -10 1.00 10.00 100.00 1,000.00 Convergence Factor 10,000.00 -30 -50 Fig.1 70 Aspect Ratio = 10.0 Mesh size = 4 x 4 Element 1 Element 2 Element 3 50 Element 4 % Error 30 10 -10 1.00 10.00 100.00 Convergence Factor -30 -50 Fig.2 1,000.00 10,000.00 70 Aspect Ratio = 10.0 Mesh size = 6 x 6 Element 1 Element 2 Element 3 50 % Error Element 4 30 10 -10 1.00 10.00 100.00 1,000.00 10,000.00 Convergence Factor -30 -50 Fig.3 70 Aspect Ratio = 10.0 Mesh size = 10 x 10 Element 1 Element 2 Element 3 50 Element 4 % Error 30 10 -10 1.00 10.00 100.00 Convergence Factor -30 -50 Fig.4 1,000.00 10,000.00 70 Aspect Ratio = 10.0 Mesh size = 14 x 14 Element 1 Element 2 Element 3 % Error 50 Element 4 30 10 -10 1.00 10.00 100.00 Convergence Factor -30 -50 Fig.5 1,000.00 10,000.00 Simply supported plate with UDL for ASR =20.0 error in deflection at centre 70 Aspect Ratio = 20.0 Mesh size = 2 x 2 Element 1 Element 2 50 Element 3 Element 4 % Error 30 10 -10 1.00 10.00 100.00 1,000.00 Convergence Factor 10,000.00 -30 -50 Fig.1 70 Aspect Ratio = 20.0 Mesh size = 4 x 4 Element 1 Element 2 Element 3 50 Element 4 % Error 30 10 -10 1.00 10.00 100.00 Convergence Factor -30 -50 Fig.2 1,000.00 10,000.00 70 Aspect Ratio = 20.0 Mesh size = 6 x 6 Element 1 Element 2 Element 3 50 % Error Element 4 30 10 -10 1.00 10.00 100.00 1,000.00 10,000.00 Convergence Factor -30 -50 Fig.3 70 Aspect Ratio = 20.0 Mesh size = 10 x 10 Element 1 Element 2 Element 3 50 Element 4 % Error 30 10 -10 1.00 10.00 100.00 Convergence Factor -30 -50 Fig.4 1,000.00 10,000.00 70 Aspect Ratio = 20.0 Mesh size = 14 x 14 Element 1 Element 2 Element 3 50 Element 4 % Error 30 10 -10 1.00 10.00 100.00 Convergence Factor -30 -50 Fig.5 1,000.00 10,000.00 Cantilever beam with tip load for ASR = 5.0 error in deflection at centre 75 Element 1 Element 2 % Error 55 Aspect Ratio = 5 No of Elements = 2 Element 3 Element 4 35 15 -5 1.00 10.00 100.00 1,000.00 Convergence Factor 10,000.00 -25 -45 Fig.1 85.00 Element 1 65.00 Element 2 Aspect Ratio = 5 No of Elements = 4 Element 3 45.00 Element 4 % Error 25.00 5.00 1.00 10.00 100.00 -15.00 1,000.00 Convergence Factor -35.00 -55.00 Fig.2 10,000.00 85.00 Element 1 65.00 Element 2 Aspect Ratio = 5 No of Elements = 6 Element 3 45.00 Element 4 % Error 25.00 5.00 1.00 10.00 100.00 -15.00 1,000.00 10,000.00 Convergence Factor -35.00 -55.00 Fig.3 85.00 Element 1 65.00 Element 2 Aspect Ratio = 5 No of Elements = 10 Element 3 45.00 Element 4 % Error 25.00 5.00 1.00 10.00 100.00 -15.00 1,000.00 Convergence Factor -35.00 -55.00 Fig.4 10,000.00 85.00 Element 1 65.00 Element 2 Aspect Ratio = 5 No of Elements = 20 Element 3 45.00 Element 4 % Error 25.00 5.00 1.00 10.00 100.00 -15.00 1,000.00 Convergence Factor -35.00 -55.00 Fig.5 10,000.00 Cantilever beam with tip load for ASR = 10.0 error in deflection at centre 75.00 Element 1 Element 2 55.00 Aspect Ratio = 10 No of Elements = 2 Element 3 Element 4 % Error 35.00 15.00 -5.00 1.00 10.00 100.00 1,000.00 Convergence Factor 10,000.00 -25.00 -45.00 Fig.1 85.00 Element 1 65.00 Element 2 Aspect Ratio = 10 No of Elements = 4 Element 3 45.00 Element 4 % Error 25.00 5.00 1.00 10.00 100.00 -15.00 1,000.00 Convergence Factor -35.00 -55.00 Fig.2 10,000.00 85.00 Element 1 65.00 Element 2 Aspect Ratio = 10 No of Elements = 6 Element 3 45.00 Element 4 % Error 25.00 5.00 1.00 10.00 100.00 -15.00 1,000.00 10,000.00 Convergence Factor -35.00 -55.00 Fig.3 85 Element 1 % Error 65 Element 2 Aspect Ratio = 10 No of Elements = 10 Element 3 45 Element 4 25 5 1.00 10.00 100.00 -15 1,000.00 Convergence Factor -35 -55 Fig.4 10,000.00 85.00 Element 1 65.00 Element 2 Aspect Ratio = 10 No of Elements = 20 Element 3 45.00 Element 4 % Error 25.00 5.00 1.00 10.00 100.00 -15.00 1,000.00 Convergence Factor -35.00 -55.00 Fig.5 10,000.00 Cantilever beam with tip load for ASR =25.0 error in deflection at centre 75 Element 1 Element 2 % Error 55 Aspect Ratio = 25 No of Elements = 2 Element 3 Element 4 35 15 -5 1.00 10.00 100.00 1,000.00 Convergence Factor 10,000.00 -25 -45 Fig.1 85.00 Element 1 65.00 Element 2 Aspect Ratio = 25 No of Elements = 4 Element 3 45.00 Element 4 % Error 25.00 5.00 1.00 10.00 100.00 -15.00 1,000.00 Convergence Factor -35.00 -55.00 Fig.2 10,000.00 85.00 Element 1 65.00 Element 2 Aspect Ratio = 25 No of Elements = 6 Element 3 45.00 Element 4 % Error 25.00 5.00 1.00 10.00 100.00 -15.00 1,000.00 10,000.00 Convergence Factor -35.00 -55.00 Fig.3 85.00 Element 1 65.00 Element 2 Aspect Ratio = 25 No of Elements = 10 Element 3 45.00 Element 4 % Error 25.00 5.00 1.00 10.00 100.00 -15.00 1,000.00 Convergence Factor -35.00 -55.00 Fig.4 10,000.00 85.00 Element 1 65.00 Element 2 Aspect Ratio = 25 No of Elements = 20 Element 3 45.00 Element 4 % Error 25.00 5.00 1.00 10.00 100.00 -15.00 1,000.00 Convergence Factor -35.00 -55.00 Fig.4 10,000.00 Cantilever beam with tip load for ASR =100.0 error in deflection at centre 75.00 Aspect Ratio = 100 No of Elements = 2 Element 1 Element 2 % Error 55.00 Element 3 Element 4 35.00 15.00 -5.00 1.00 10.00 100.00 1,000.00 Convergence Factor 10,000.00 -25.00 -45.00 Fig.1 85.00 Element 1 65.00 Element 2 Aspect Ratio = 100 No of Elements = 4 Element 3 45.00 Element 4 % Error 25.00 5.00 1.00 10.00 100.00 -15.00 1,000.00 Convergence Factor -35.00 -55.00 Fig.2 10,000.00 85.00 Aspect Ratio = 100 No of Elements = 6 Element 1 65.00 Element 2 Element 3 45.00 Element 4 % Error 25.00 5.00 1.00 10.00 100.00 -15.00 1,000.00 10,000.00 Convergence Factor -35.00 -55.00 Fig.3 85.00 65.00 Element 1 Aspect Ratio = 100 No of Elements = 10 Element 2 45.00 Element 3 Element 4 % Error 25.00 5.00 1.00 10.00 100.00 -15.00 1,000.00 Convergence Factor -35.00 -55.00 Fig.4 10,000.00 85.00 Element 1 65.00 Element 2 Aspect Ratio = 100 No of Elements = 20 Element 3 45.00 Element 4 % Error 25.00 5.00 1.00 10.00 100.00 -15.00 1,000.00 Convergence Factor -35.00 -55.00 Fig.5 10,000.00 Cantilever beam with tip load for ASR = 200.0 error in deflection at centre 75.00 Element 1 Element 2 55.00 Aspect Ratio = 200 No of Elements = 2 Element 3 Element 4 % Error 35.00 15.00 -5.00 1.00 10.00 100.00 1,000.00 Convergence Factor 10,000.00 -25.00 -45.00 Fig.1 85.00 Element 1 65.00 Element 2 Aspect Ratio = 200 No of Elements = 4 Element 3 45.00 Element 4 % Error 25.00 5.00 1.00 10.00 100.00 -15.00 1,000.00 Convergence Factor -35.00 -55.00 Fig.2 10,000.00 85.00 Element 1 65.00 Element 2 Aspect Ratio = 200 No of Elements = 6 Element 3 45.00 Element 4 % Error 25.00 5.00 1.00 10.00 100.00 -15.00 1,000.00 10,000.00 Convergence Factor -35.00 -55.00 Fig.3 85.00 65.00 Element 1 Element 2 45.00 Aspect Ratio = 200 No of Elements = 10 Element 3 Element 4 % Error 25.00 5.00 1.00 10.00 100.00 -15.00 1,000.00 Convergence Factor -35.00 -55.00 Fig.4 10,000.00 85.00 Element 1 65.00 Element 2 Aspect Ratio = 200 No of Elements = 20 Element 3 45.00 Element 4 % Error 25.00 5.00 1.00 10.00 100.00 -15.00 1,000.00 Convergence Factor -35.00 -55.00 Fig.5 10,000.00 Cantilever beam with tip load for ASR =400.0 error in deflection at centre 75.00 Element 1 Element 2 55.00 Aspect Ratio = 400 No of Elements = 2 Element 3 Element 4 % Error 35.00 15.00 -5.00 1.00 10.00 100.00 1,000.00 Convergence Factor 10,000.00 -25.00 -45.00 Fig.1 85.00 Element 1 65.00 Element 2 Aspect Ratio = 400 No of Elements = 4 Element 3 45.00 Element 4 % Error 25.00 5.00 1.00 10.00 100.00 -15.00 1,000.00 Convergence Factor -35.00 -55.00 Fig.2 10,000.00 85.00 Element 1 65.00 Element 2 Aspect Ratio = 400 No of Elements = 6 Element 3 45.00 Element 4 % Error 25.00 5.00 1.00 10.00 100.00 -15.00 1,000.00 10,000.00 Convergence Factor -35.00 -55.00 Fig.3 85.00 65.00 Element 1 Element 2 45.00 Aspect Ratio = 400 No of Elements = 10 Element 3 Element 4 % Error 25.00 5.00 1.00 10.00 100.00 -15.00 1,000.00 Convergence Factor -35.00 -55.00 Fig.4 10,000.00 85.00 Element 1 65.00 Element 2 Aspect Ratio = 400 No of Elements = 20 Element 3 45.00 Element 4 % Error 25.00 5.00 1.00 10.00 100.00 -15.00 1,000.00 Convergence Factor -35.00 -55.00 Fig.5 10,000.00 2. Rhombic Plate under UDL y E=10.5e5 psi υ=0.3 h=0.125 in q=0.25066 psi ∙ ∙ ∙ 2 3 ∙ 1 ∙4 ∙5 5 6 12” 450 x 12” Element Mesh DOF 4x4 75 MR_FE_11 4x4 75 MR_FE_21 4x4 75 MR_FE_31 4x4 75 MR_FE_41 4x4 75 DKT2 HSM 4x4 75 ACM 8x6 189 HCT 8x6 189 Experimental Value 1 one point integration; 2 1 0.3132 0.3133 0.3132 0.3133 0.304 0.264 0.296 0.281 0.297 2 0.2059 0.2010 0.2059 0.2060 0.198 0.173 0.198 0.188 0.204 3 0.1144 0.1144 0.1144 0.1144 0.113 0.100 0.114 0.111 0.121 4 0.1255 0.1256 0.1255 0.1256 0.121 0.095 0.114 0.111 0.129 5 0.05239 0.05241 0.05239 0.05241 0.055 0.043 0.052 0.049 0.056 6 0.02053 0.02054 0.02053 0.02054 0.028 0.021 0.020 0.018 0.022 Three point integration; DKT – Discrete Krichhoff Theory element , Jean-Louis Batoz et al, A study of three-node triangular plate bending elements, international journal for numerical methods in engineering, Vol. 15, 1771-1812 (1980). 3. Twisting of a square plate 5.0lb A 1 1 B 6 ∙ ∙ ∙ ∙ 2 4 9 8 ∙ 9 6 7 2 ∙ 1 ∙ 2 Mesh (b) Mesh (b) Node No X-co Y-co Mesh (c) Element Type Point C* Node No X-co Y-co ∙ ∙ 4 1 0 0 2 0 4 1 2 0 0 0 2 3 0 6 3 0 8 4 0 8 4 5 0 5 4 0 5 5 4 6 3 3 DKT HSM ACM HCT 0.24960 0.24960 .24972 0.25002 * 0.24960 Three point integration 7 1 ∙ Mesh 8 ∙9 1 14 ∙ ∙ 13 4 ∙ ∙8 7 5 Mesh (c) 7 8 0 8 4 8 ∙15 ∙ 5 ∙ 6 6.2 8 7 3 5 ∙ 11 6∙ 3 1 ∙ 16 ∙ 3 5 ∙ 12 ∙ 3∙ 8 3 Mesh (a) D 8.0” 4 2 4 8.0” E=10000 psi h=1.0” υ=0.3 3 2 C 8 8 6.2 9 6 0 9 8 8 10 6 2 MR_FE_1 11 7 5 12 6 8 MR_FE_2 a 0.25740 0.25740 b 0.18963 0.18963 c 0.19229 0.19229 (Exact thin plate solution) 13 8 0 14 8 1 15 8 5 16 8 8 MR_FE_3 MR_FE_4 0.25742 0.18945 0.19218 0.25739 0.19218 0.19239 4. Cantilever Beam (Tip Load) z q=100 x 2h L N HFE_1 HFE_2 2 4 8 12 20 24 30 36 Reddy * Exact Solution 1.8136 6.2233 15.8701 22.2602 28.0410 29.3511 30.5177 31.1911 1.8136 6.2233 15.8701 22.2602 28.0410 29.3511 30.5177 31.1911 N HFE_1 HFE_2 2 4 8 12 20 24 30 36 0.2626 0.4302 0.5118 0.5305 0.5406 0.5424 0.5439 0.5447 0.2626 0.4302 0.5118 0.5305 0.5406 0.5424 0.5439 0.5447 Reddy * Exact Solution Timo_FE_1 L/2h=160/12 Timo_FE_3 FE_NSF_1 FE_NSF_3 32.2712 32.2391 32.2712 32.2712 (6 elements with 1000 CF) (6 elements with 1000 CF) (6 elements with 1000 CF) (6 elements with 1000 CF) HFE_1 HFE_2 0.7867 2.0073 3.2797 3.7158 3.9874 4.0381 4.0806 4.1040 0.7867 2.0073 3.2797 3.7158 3.9874 4.0381 4.0806 4.1040 Timo_FE_1 L/2h=40/12 Timo_FE_2 FE_NSF_3 4.1100 4.1258 4.1218 (6 elements with 1000 CF) (6 elements with 1000 CF (6 elements with 1000 CF) (6 elements with 1000 CF) FE_NSF_1 FE_NSF_3 4.1567 4.1317 FE_NSF_1 FE_NSF_3 0.5366 0.5362 0.5424 0.5419 ( 6 elements with 1000 CF) ( 6 elements with 1000 CF) ( 6 elements with 1000 CF) ( 6 elements with 1000 CF) 0.54588 0.5333 FE_NSF_1 4.1140 32.823 32.7844 Timo_FE_1 L/2h=80/12 Timo_FE_3 HFE_1 HFE_2 0.02194 0.02367 0.02414 0.02423 0.02428 0.02194 0.02367 0.02414 0.02423 0.02428 Timo_FE_1 L/2h=12/12 Timo_NFE_3 0.02264 0.02264 0.02419 0.02418 ( 6 elements with 1000 CF) ( 6 elements with 1000 CF) ( 6 elements with 1000 CF) ( 6 elements with 1000 CF) 0.02393 0.02052 5. Simply Supported Beam (Uniformly distributed load) z Δ N 2 4 8 12 20 24 30 36 HFE_1 0.8254 3.6431 9.8570 13.9791 17.7108 18.5568 19.3102 19.7452 HFE_2 0.8254 3.6431 9.8570 13.9791 17.7108 18.5568 19.3102 19.7452 q=10 x L Timo_FE_1 20.326 ( 10 elements with 1000 CF) Reddy * Exact Solution L/2h=160/12 Timo_FE_3 2h FE_NSF_1 FE_NSF_3 20.306 20.374 20.354 (10 elements with 1000 CF) (10 elements with 1000 CF) ( 10 elements with 1000 CF) HFE_1 0.1849 0.6046 1.0482 1.2009 1.2960 1.3138 1.3287 1.3369 HFE_2 0.1849 0.6046 1.0482 1.2009 1.2960 1.3138 1.3287 1.3369 L/2h=80/12 Timo_FE_1 Timo_FE_3 HFE_1 HFE_2 2 4 8 12 20 24 30 36 0.03475 0.07202 0.09064 0.09491 0.09723 0.09764 ----------------- 0.03475 0.07202 0.09064 0.09491 0.09723 0.09764 ----------------- L/2h=40/12 Timo_FE_1 Timo_FE_3 FE_NSF_3 1.3139 1.3271 1.3259 ( 10 elements with 1000 CF) ( 10 elements with 1000 CF) ( 10 elements with 1000 CF ( 10 elements with 1000 CF FE_NSF_1 FE_NSF_3 1.3486 1.3408 FE_NSF_1 FE_NSF_3 0.09339 0.09333 0.09634 0.09628 ( 10 elements with 1000 CF) ( 10 elements with 1000 CF) ( 10 elements with 1000 CF) ( 10 elements with 1000 CF) 0.09770 0.09576 FE_NSF_1 1.3151 20.717 20.6892 N Reddy * Exact Solution Δ HFE_1 HFE_2 0.0016486 0.0021069 0.0022298 0.0022529 0.0022649 ------------------------------- 0.0016486 0.0021069 0.0022298 0.0022529 0.0022649 ------------------------------- L/2h=12/12 Timo_FE_1 Timo_FE_3 0.001979 0.001980 0.002230 0.002210 ( 10 elements with 1000 CF) ( 10 elements with 1000 CF) ( 10 elements with 1000 CF) ( 10 elements with 1000 CF) 0.002220 0.002082