Hide last authors
Hamid Richard Allili 49.1 1 (% class="row" %)
2 (((
Hamid Richard Allili 3.2 3 Contents
4
5 {{toc depth="3"/}}
6
7 ----
8
Iwona Budny Bjergø 77.1 9 (% style="text-align: justify;" %)
Hamid Richard Allili 49.1 10 Analysis of laminated type shell structures became available by a new mechanical model implemented into FEM-Design, based on the laminated shell theory. From civil engineering point of view, the most popular field of application is the cross laminated timber (CLT) panel, although the theory in itself is more general, it is applicable for any kind of laminated composite surface structure. As the main purpose of this feature is to calculate and design CLT panels, the currently existing Timber plate and Timber wall tools are supplemented with this calculation model. For further theoretical informations about CLT panels click [[here>>http://download.strusoft.com/FEM-Design/inst190x/documents/theory_of_laminated_composite_shells_CLT_fd19_v1.0.pdf]].
Hamid Richard Allili 3.2 11
Hamid Richard Allili 44.1 12 = Panel definition =
Hamid Richard Allili 3.2 13
Hamid Richard Allili 39.1 14 [[image:1574851449204-676.png]]
Hamid Richard Allili 3.2 15
16
Iwona Budny Bjergø 77.1 17 (% style="text-align: justify;" %)
Hamid Richard Allili 39.1 18 Although, the theory used for the calculation of displacements and stresses is general, the application data (e.g. deformation factor, service class, etc.) and design methods for CLT panels are very specific and standard dependent. In order to preserve the possibility of general application, two new options are added to the original mechanical model used for the calculation of timber shell structures (Orthotropic shell): Cross laminated timber and General laminated composite (GLC).
Hamid Richard Allili 3.2 19
Iwona Budny Bjergø 77.1 20
StruSoft Developers 68.2 21 [[image:CLT.gif]]
Hamid Richard Allili 3.2 22
StruSoft Developers 68.2 23 [[image:GeneralLaminatedComposite.gif]]
24
Hamid Richard Allili 3.2 25
Iwona Budny Bjergø 77.1 26 (% style="text-align: justify;" %)
Hamid Richard Allili 43.1 27 For CLT panels, both analysis results (displacements and stresses) and design calculations are available, while for GLC panels only the first one is provided. These panel types are stored in different libraries, but their definition is very similar, we can define them layer by layer. In case of CLT, adding a new layer is possible by clicking on the material cell of the table, by this the original timber material library pops up, where the constituent material of the current layer can be selected. After the selection, the program automatically fills all necessary data of the current layer, including mechanical properties (for analysis results) and limit stresses (for design calculations).
Hamid Richard Allili 3.2 28
Iwona Budny Bjergø 77.1 29
Hamid Richard Allili 39.1 30 [[image:1574852438069-859.png]]
Hamid Richard Allili 5.2 31
Iwona Budny Bjergø 77.1 32 (% style="text-align: justify;" %)
Hamid Richard Allili 39.1 33 It is very important that among the required layer data, there are some properties not specified by the Eurocode, these can be assumed based on the existing ones according to the following (in case the manufacturer does not specify different values for them):
Hamid Richard Allili 5.2 34
Iwona Budny Bjergø 77.1 35 (% style="text-align: justify;" %)
Hamid Richard Allili 39.1 36 • G,,yz,, (G,,rolling,,) = G,,mean,, / 10
Hamid Richard Allili 5.2 37
Iwona Budny Bjergø 77.1 38 (% style="text-align: justify;" %)
Hamid Richard Allili 39.1 39 • nu,,xy,, = 0.2
Hamid Richard Allili 5.2 40
Iwona Budny Bjergø 77.1 41 (% style="text-align: justify;" %)
Hamid Richard Allili 39.1 42 • f,,Rk,, = f,,vk,, / 2
Hamid Richard Allili 5.2 43
Iwona Budny Bjergø 77.1 44 (% style="text-align: justify;" %)
Hamid Richard Allili 39.1 45 • f,,xyk,, = f,,vk,,
Hamid Richard Allili 5.2 46
Iwona Budny Bjergø 77.1 47
48 (% style="text-align: justify;" %)
Hamid Richard Allili 43.1 49 Of course, every value can be overwritten on demand. Besides the layers, the default deformation factors by service classes and stiffness reduction factors also need to be specified for a CLT library element. The new cross laminated timber library is filled up with the products of many famous manufacturers by default, new elements can be easily created based on them.
Hamid Richard Allili 5.2 50
Iwona Budny Bjergø 77.1 51 (% style="text-align: justify;" %)
Hamid Richard Allili 43.1 52 The definition of GLC library elements is very similar, except that only the mechanical properties are necessary to define.
Hamid Richard Allili 5.2 53
Iwona Budny Bjergø 77.1 54 (% style="text-align: justify;" %)
Hamid Richard Allili 43.1 55 For all the three mechanical types a //Display stiffness// option is available to show the element stiffness matrix (refer to mid-plane) of the panels used in the calculations (and/or check its singularity), including the "B" submatrix responsible for the coupling effect.
56
Iwona Budny Bjergø 77.1 57
Hamid Richard Allili 25.1 58 = Results =
Hamid Richard Allili 17.2 59
Hamid Richard Allili 28.1 60 == Analysis ==
Hamid Richard Allili 17.2 61
Iwona Budny Bjergø 77.1 62 (% style="text-align: justify;" %)
Hamid Richard Allili 26.1 63 The following analysis results are available for CLT/GLC panels :
64
Hamid Richard Allili 33.1 65 * load case
66 * load combination
67 * maximum of load combination
68 * maximum of load groups
69 * influence line and moving load maximum.
70
Iwona Budny Bjergø 77.1 71 (% style="text-align: justify;" %)
Hamid Richard Allili 26.1 72 Displacements and internal forces are displayed in the same way as for the existing non-laminated shells.
73
Iwona Budny Bjergø 77.1 74 (% style="text-align: justify;" %)
Hamid Richard Allili 26.1 75 For displaying stresses some further options are needed due to the laminated structure of these shells:
Hamid Richard Allili 33.1 76
77 * a layer has to be selected
78 * //Shell local system// or  //Layer local system //coordinate system has to be chosen
79
Iwona Budny Bjergø 77.1 80 (% style="text-align: justify;" %)
Hamid Richard Allili 26.1 81 For example, the physical direction of a displayed Sigma x' stress varies according to the selected system, if shell and layer local system is not identical, which means the angle Theta defined in the library for the layer is not zero.
82
StruSoft Developers 70.2 83 [[image:CLT_Simga.gif]]
Hamid Richard Allili 17.2 84
StruSoft Developers 70.2 85
Iwona Budny Bjergø 77.1 86 (% style="text-align: justify;" %)
Hamid Richard Allili 31.1 87 It is worth to mention that in contrary to the non-laminated shells, the transverse shear stresses (Tau y'z' and Tau x'z') can be also displayed at the top and bottom of layers besides the center, as in case of some intermediate layer they are not necessarily zero (for non-laminated shells, due to the parabolic stress distribution the top and bottom values are always zero, only the center value can be selected from the shell stresses list).
Hamid Richard Allili 17.2 88
Iwona Budny Bjergø 77.1 89 (% class="wikigeneratedid" style="text-align: justify;" %)
90 ==== ====
91
92 (% style="text-align: justify;" %)
Hamid Richard Allili 30.1 93 ==== Stress detailed results ====
Hamid Richard Allili 27.1 94
Iwona Budny Bjergø 77.1 95 (% style="text-align: justify;" %)
Hamid Richard Allili 27.1 96 Two types of detailed result are available for stresses.
97
Iwona Budny Bjergø 77.1 98
99 (% style="text-align: justify;" %)
Hamid Richard Allili 30.1 100 ===== //Point based stress detailed result// =====
Hamid Richard Allili 27.1 101
Iwona Budny Bjergø 77.1 102 (% style="text-align: justify;" %)
Hamid Richard Allili 31.1 103 User can select an arbitrary point on the CLT/GLC panel, in the detailed result the geometry of the shell and the five stress components are displayed. As the whole section of the shell can be seen here, the coordinate system selector is supplemented with each layer's local system options. In case of maximum result (maximum of load combinations, etc.) plenty of maximum criteria are available, which can be grouped by the following:
Hamid Richard Allili 29.1 104
Hamid Richard Allili 33.1 105 * All components maximum (e.g. All components+): search for the combination(s) component by component which results the largest positive value of the stress component along all the layers at the selected point, on the stress figures the result of the combinations belonging to the components is displayed (note that there can be five different combination displayed in the detailed result)
106 * All layer maximum by stress type (e.g. All layer, Sigma x+): search for the combination which results the largest positive x directional normal stress along all the layers at the selected point, on all the five stress figures the result of this combination is displayed
107 * Layer maximum by stress type (e.g. 2. layer, Sigma x+): search for the combination which results the largest positive x directional normal stress in the second layer at the selected point, on all the five stress figures the result of this combination is displayed
Hamid Richard Allili 17.2 108
Iwona Budny Bjergø 77.1 109 (% style="text-align: justify;" %)
StruSoft Developers 74.2 110 [[image:CLT_DtlRes_Short.gif]]
Hamid Richard Allili 39.1 111
Iwona Budny Bjergø 77.1 112 (% class="wikigeneratedid" style="text-align: justify;" %)
113 ===== =====
114
115 (% style="text-align: justify;" %)
Hamid Richard Allili 30.1 116 ===== //Shell based stress detailed result// =====
Hamid Richard Allili 17.2 117
Iwona Budny Bjergø 77.1 118 (% style="text-align: justify;" %)
Hamid Richard Allili 29.1 119 Due to the numerous options, finding maximum stresses by components on the shell can be quite time consuming, especially in case of complex loading of the structure. In order to overcome this difficulty and make the maximum finding process much easier a shell based option is also implemented, where User only has to select a shell.
120
Iwona Budny Bjergø 77.1 121 (% style="text-align: justify;" %)
Hamid Richard Allili 18.2 122 [[image:1574697194599-496.png]]
Hamid Richard Allili 17.2 123
Iwona Budny Bjergø 77.1 124 (% style="text-align: justify;" %)
Hamid Richard Allili 46.1 125 The detailed result the following options are available:
126
Iwona Budny Bjergø 77.1 127 (% style="text-align: justify;" %)
Hamid Richard Allili 46.1 128 [[image:1575036940703-167.png||height="475" width="910"]]
129
Iwona Budny Bjergø 77.1 130 (% style="text-align: justify;" %)
Hamid Richard Allili 17.2 131 It is only available for maximum type results, the maximum criteria are the same as for the point based detailed result, except one significant difference: in this case the searching is not limited to a node, the program checks all node on the shell according to the selected criteria. For the first criteria group (All components maximum) the five stress component maximums may arise at five different nodes on the shell (also possibly from five different combinations), this result is excellent to see the overall maximum stresses on the shell considering simultaneously all nodes and all combinations. These nodes are displayed with position and node number on the geometry figure. In case of the second (All layer maximum by stress type) and third (Layer maximum by stress type) maximum criteria group the search focuses on one stress component, thus all stress figures display the result of the same node that provides the maximum for the selected component with simultaneous stress figures at this node for the other components. In the display options the scale/size of the figures and display/font of the values can be specified.
132
Iwona Budny Bjergø 77.1 133 (% class="wikigeneratedid" style="text-align: justify;" %)
134 == ==
135
136 (% style="text-align: justify;" %)
Hamid Richard Allili 32.1 137 == Deflection check ==
138
Iwona Budny Bjergø 77.1 139 (% style="text-align: justify;" %)
Hamid Richard Allili 32.1 140 Deflection check of cross-laminated timber panels can be performed for serviceability limit states. For further information see description of Shell deflection check.
141
Hamid Richard Allili 34.2 142 (% class="box infomessage" %)
143 (((
Iwona Budny Bjergø 77.1 144 (% style="text-align: justify;" %)
Hamid Richard Allili 32.1 145 By setting different deformation factors in the application data of the panel for characteristic and quasi-permanent combination types, both the instantaneous and long-term deflections can be checked properly according to the EC, respectively.
Hamid Richard Allili 34.2 146 )))
Hamid Richard Allili 32.1 147
Iwona Budny Bjergø 77.1 148 (% class="wikigeneratedid" style="text-align: justify;" %)
149 == ==
150
151 (% style="text-align: justify;" %)
Hamid Richard Allili 28.1 152 == Design ==
Hamid Richard Allili 17.2 153
Iwona Budny Bjergø 77.1 154 (% style="text-align: justify;" %)
Hamid Richard Allili 32.1 155 Cross-laminated timber panels are supported with design calculations for ULS combinations. It is available at Timber design tab, CLT panel design.
Hamid Richard Allili 17.2 156
Iwona Budny Bjergø 77.1 157 (% style="text-align: justify;" %)
Hamid Richard Allili 17.2 158 [[image:1574691194768-349.png]]
159
Iwona Budny Bjergø 77.1 160 (% style="text-align: justify;" %)
Hamid Richard Allili 32.1 161 The following design checking criteria are available:
162
Hamid Richard Allili 34.1 163 * stress checks by EC5
164 ** tension/compression and bending in both grain and perpendicular to grain direction
165 ** transverse shear stresses and rolling shear.
Hamid Richard Allili 32.1 166
Iwona Budny Bjergø 77.1 167 (% style="text-align: justify;" %)
Hamid Richard Allili 34.1 168 In case of CLT panels these checks are extended by performing them layer by layer (in the current layer's local system), at top and bottom or at parabola maximum in case of transverse shear stresses.
Hamid Richard Allili 32.1 169
Hamid Richard Allili 34.1 170 * interaction checks
171 ** shear interaction
172 ** tension/compression and shear.
Hamid Richard Allili 32.1 173
Iwona Budny Bjergø 77.1 174 (% style="text-align: justify;" %)
Hamid Richard Allili 34.1 175 As these are not included in EC5, in the calculation parameter of the CLT panelUser can specify whether to consider them during the design calculation or not.
Hamid Richard Allili 32.1 176
Hamid Richard Allili 34.1 177 * shell buckling check
178
Iwona Budny Bjergø 77.1 179 (% style="text-align: justify;" %)
Hamid Richard Allili 34.1 180 It is performed only for those buckling regions, which has non-zero buckling factor, also for those layers, which are less than 45° from the buckling direction.
181
182 * torsional check
183
Iwona Budny Bjergø 77.1 184 (% style="text-align: justify;" %)
Hamid Richard Allili 34.1 185 It is typically applied for walls (in plane loaded structures), the "no glue at narrow sides" option must be checked in the application data.
186
Iwona Budny Bjergø 77.1 187 (% style="text-align: justify;" %)
Hamid Richard Allili 57.1 188 These methods are based on different standards and scientific papers, further information about the detailed checking process can be found in the theory manual of this feature: [[Theory of Laminated Composite Shells - CLT application>>http://download.strusoft.com/FEM-Design/inst190x/documents/theory_of_laminated_composite_shells_CLT_fd19_v1.0.pdf]]. In the detailed result of the CLT panel the performed design calculations together with a geometry figure showing the critical nodes are displayed.
Hamid Richard Allili 42.1 189
Iwona Budny Bjergø 77.1 190
191 (% style="text-align: justify;" %)
Hamid Richard Allili 42.1 192 [[image:1574853711423-165.png]]
Iwona Budny Bjergø 77.1 193
Hamid Richard Allili 48.1 194 )))
Copyright 2020 StruSoft AB
FEM-Design Wiki