SIST-TP CEN/TR 17603-32-22:2022

SLOVENSKI STANDARD
01-september-2022
Vesoljska tehnika - Priročnik za oblikovanje vstavkov
Space engineering - Insert design handbook
Raumfahrttechnik - Handbuch zu Einsätzen
Ingénierie spatiale - Manuel de conception d’inserts
Ta slovenski standard je istoveten z: CEN/TR 17603-32-22:2022
ICS:
49.140 Vesoljski sistemi in operacije Space systems and
operations
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL REPORT CEN/TR 17603-32-22

RAPPORT TECHNIQUE
TECHNISCHER BERICHT
June 2022
ICS 49.030.99; 49.140
English version
Space engineering - Insert design handbook
Ingénierie spatiale - Manuel de conception d'inserts Raumfahrttechnik - Handbuch zu Einsätzen

This Technical Report was approved by CEN on 17 May 2022. It has been drawn up by the Technical Committee CEN/CLC/JTC 5.

CEN and CENELEC members are the national standards bodies and national electrotechnical committees of Austria, Belgium,
Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia,
Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.

CEN-CENELEC Management Centre:
Rue de la Science 23, B-1040 Brussels
© 2022 CEN/CENELEC All rights of exploitation in any form and by any means
Ref. No. CEN/TR 17603-32-22:2022 E
reserved worldwide for CEN national Members and for
CENELEC Members.
Table of contents
European Foreword . 27
1 Scope . 28
2 References . 29
3 Terms, definitions and abbreviated terms . 30
4 Insert system . 67
4.1 Insert systems and components . 67
4.1.1 Inserts . 67
4.1.2 Insert system components . 69
4.1.3 Loading modes . 70
5 Insert . 71
5.1 General . 71
5.2 Types. 71
5.2.1 General . 71
5.2.2 Group A . 71
5.2.3 Group B . 73
5.2.4 Group C . 73
5.2.5 Potting methods . 74
5.2.6 Injection . 74
5.3 Sizes. 75
5.3.1 General . 75
5.3.2 Standards . 75
5.3.3 Strength . 76
5.3.4 Standardised diameters . 77
5.3.5 Standardised heights . 78
5.4 Materials . 79
5.4.1 General . 79
5.4.2 Aluminium alloys . 80
5.4.3 Titanium alloys . 80
5.4.4 Steels . 81
5.4.5 Material selection . 81
5.5 Surface protection. 81
5.5.1 General . 81
5.5.2 Aluminium alloy . 82
5.6 References . 83
5.6.1 General . 83
5.6.2 ECSS standards . 83
6 Sandwich panels . 84
6.1 Sandwich properties . 84
6.1.1 Insert load-bearing capability . 84
6.1.2 Sandwich dimensions . 85
6.2 Face sheet properties . 85
6.2.1 Tensile and compressive loading . 85
6.2.2 Shear loading . 87
6.2.3 Other loads . 89
6.3 Core properties . 90
6.3.1 Types of cores . 90
6.3.2 Hexagonal core . 90
6.4 Core shear modulus . 94
6.4.1 Data sources . 94
6.5 Core shear strength . 94
6.5.1 Data sources . 95
6.6 Core tensile strength . 95
6.6.1 Data sources . 95
6.6.2 Aluminium core . 95
6.6.3 Non-metallic cores . 95
6.7 Core compressive strength . 96
6.8 Core to face sheet bond . 96
6.9 References . 96
7 Embedding of inserts . 97
7.1 Potting compounds . 97
7.1.1 Commercial products . 97
7.1.2 Modification of properties . 99
7.2 Potting and equivalent dimensions . 99
7.2.1 Insert load capability . 99
7.2.2 Increasing insert tensile capability . 101
7.3 Effective potting radius, or equivalent dimension . 101
7.3.1 Minimum value . 102
7.3.2 Average value . 102
7.3.3 Relationship of minimum and average values . 103
7.4 Real potting radius, or equivalent dimension . 104
7.4.1 Minimum value . 104
7.4.2 Average value . 104
7.4.3 Relationship between minimum and average values . 104
7.5 Potting height . 105
7.5.1 Full potting . 105
7.5.2 Partial potting . 106
7.5.3 Minimum value . 106
7.5.4 Average value . 106
7.5.5 Relationship of minimum and average values . 106
7.6 Potting mass . 108
7.6.1 Effect of core and insert characteristics . 108
7.6.2 Total mass of insert system . 110
7.7 References . 110
7.7.1 General . 110
7.7.2 ECSS standards . 110
8 Mechanics of sandwich structures . 111
8.1 Structural sandwich concept . 111
8.1.1 Properties of constituent materials . 112
8.1.2 Fundamentals of classical ‘antiplane’ sandwich theory . 113
8.2 Structural failure modes . 116
8.2.1 Global failure modes . 117
8.2.2 Local failure modes . 118
8.3 Load introduction aspects and discontinuities . 118
8.3.1 General . 118
8.3.2 Local bending response . 119
8.3.3 Antiplane-type theory . 120
8.3.4 Finite element analysis . 120
8.3.5 Elastic foundation model . 120
8.3.6 Transverse flexibility . 120
8.3.7 Higher-order sandwich beam theory . 120
8.4 Sandwich plates with potted inserts . 121
8.4.1 Classification of potted insert types . 121
8.4.2 Load transfer . 122
8.4.3 External load cases . 122
8.4.4 Example . 124
8.4.5 Purpose of the potting compound . 129
8.4.6 Design guidelines . 129
8.5 Remarks . 130
8.5.1 General . 130
8.5.2 Antiplane theories . 130
8.5.3 Higher-order theories . 131 ®
8.5.4 ESAComp . 131
8.6 References . 132
8.6.1 General . 132
8.6.2 ECSS standards . 134
9 Design aspects . 135
9.1 Design parameters . 135
9.1.1 Metal face sheets . 137
9.1.2 Composite face sheets . 137
9.2 Main load directions . 138
9.2.1 Out-of-plane load . 138
9.2.2 In-plane load . 139
9.3 References . 139
9.3.1 General . 139
9.3.2 ECSS standards . 139
10 Design considerations . 140
10.1 Insert arrangement . 140
10.1.1 Load capability . 141
10.2 Load conditions . 142
10.2.1 General . 142
10.2.2 Design guide . 144
10.3 Mounting modes . 148
10.3.1 General . 148
10.3.2 Flush-mounted insert . 148
10.3.3 Recessed insert . 148
10.3.4 Protruding insert . 149
10.3.5 Bonded flange . 150
10.4 Junction of components . 150
10.4.1 General . 150
10.4.2 Minimum value . 151
10.5 Adequate insert design . 152
10.5.1 Insert arrangement . 152
10.5.2 Typical spacecraft design . 152
10.5.3 Examples . 153
10.6 Selection of inserts . 153
10.6.1 General . 153
10.6.2 Sufficient static strength . 154
10.6.3 Safety factor . 155
10.7 Minimum and average insert capability . 155
10.7.1 Minimum . 155
10.7.2 Average . 156
10.8 Pre-design . 156
10.8.1 Load path for in-plane forces . 157
10.8.2 Load path for transverse forces . 159
10.8.3 Transverse and in-plane load interaction . 160
10.8.4 Proximity and edge effects . 160
10.9 Failure modes . 160
10.9.1 General . 160
10.9.2 Failures under out-of-plane loads . 161
10.9.3 Failures under in-plane loads . 166
10.10 References . 168
10.10.1 General . 168
11 Design flow chart . 169
11.1 Introduction . 169
11.2 Flow chart: Predefined sandwich and loads . 169
11.3 Flow chart: Variable main parameters . 171
11.4 References . 172
11.4.1 General . 172
12 Tensile strength . 173
12.1 Normal tensile load . 173
12.1.1 General . 173
12.1.2 Failure modes . 173
12.1.3 Shear rupture: core surrounding the potting . 174
12.1.4 Tensile rupture: core underneath the potting . 175
12.1.5 Tensile rupture: potting underneath the insert . 176
12.2 Basic parameters . 176
12.2.1 Out-of-plane loads: Insert strength . 179
12.3 Minimum and average design values . 181
12.3.1 Overview . 181
12.3.2 Minimum insert design values . 181
12.3.3 Average insert values . 182
12.4 Safety factors . 183
12.4.1 Load capability . 183
12.4.2 Failure modes . 184
12.5 Permissible tensile loads . 184
12.5.1 General . 184
12.5.2 Insert capability graphs . 184
12.5.3 Design values . 184
12.6 Influence of insert height . 185
12.6.1 Insert capability graphs . 185
12.6.2 Different insert heights . 185
12.7 Composite face sheet . 187
12.7.1 Effect of anisotropy . 187
12.7.2 Loading by moments . 187
12.8 References . 187
12.8.1 General . 187
13 Compressive strength . 188
13.1 Normal compressive load . 188
13.1.1 General . 188
13.1.2 Partially-potted inserts . 188
13.1.3 Potting strength . 188
13.1.4 Increased face sheet thickness . 188
13.1.5 Insert capabilities . 189
13.2 Permissible compressive loads . 189
13.2.1 Graphs of permissible static insert loads . 189
13.3 Composite face sheet . 189
14 Shear strength . 191
14.1 Shear (in-plane) load . 191
14.1.1 Effect of in-plane load . 191
14.1.2 Effect of face sheet material . 192
14.1.3 Effect of partial clamping . 192
14.2 Permissible shear load . 192
14.3 Composite face sheet . 193
14.3.1 Strength . 193
14.3.2 Face sheets . 196
14.3.3 CFRP face sheets . 196
14.3.4 Effect of panel layout . 201
14.3.5 Sensitivity of insert strength in face sheets . 202
14.3.6 Effect of thin CFRP face sheet . 203
14.4 References . 204
14.4.1 General . 204
15 Bending strength . 205
15.1 Bending load . 205
15.2 Permissible bending load . 206
15.3 Composite face sheet . 207
15.4 References . 208
15.4.1 General . 208
16 Torsional strength . 209
16.1 Torsional load . 209
16.2 Permissible torsion load . 209
16.2.1 General . 209
16.2.2 Metallic core . 209
16.2.3 Non-metallic core . 210
16.3 Composite face sheets . 210
16.4 References . 211
16.4.1 General . 211
17 Combined loads . 212
17.1 Inclined load . 212
17.2 General load combinations . 213
18 Edge influence . 214
18.1 Edge distance: Out-of-plane loading . 214
18.2 Edge distance: Shear loaded . 215
18.2.1 General . 215
18.2.2 Metallic face sheets . 216
18.2.3 Non-metallic face sheets . 216
18.3 Composite face sheets . 217
18.3.1 Out-of-plane loading . 217
18.3.2 In-plane loaded inserts . 217
18.4 References . 217
18.4.1 General . 217
19 Insert groups . 218
19.1 Two inserts: Loaded in same direction . 218
19.1.1 General . 218
19.1.2 Close inserts . 218
19.1.3 Distant inserts . 219
19.1.4 Effect of load . 219
19.2 Two inserts: Loaded in opposite directions . 220
19.2.1 General . 220
19.2.2 Close inserts . 221
19.2.3 Distant inserts . 221
19.3 Series of inserts: Loaded in same direction. 221
19.3.1 Overview . 221
19.3.2 First and last inserts . 221
19.3.3 Intermediate inserts . 222
19.3.4 Example . 222
19.4 Series of inserts: Loaded in opposite directions . 223
19.4.1 Overview . 223
19.4.2 First and last insert . 224
19.4.3 Intermediate inserts . 224
19.5 Insert groups: Loaded in same direction . 224
19.5.1 General . 224
19.5.2 Equal and equidistant inserts . 224
19.6 Composite face sheets . 226
19.6.1 Out-of-plane loading . 226
19.6.2 In-plane loaded inserts . 226
19.7 References . 226
19.7.1 General . 226
20 Stiffness . 228
20.1 Introduction . 228
20.1.1 Overview . 228
20.1.2 Rotational stiffness . 228
20.1.3 In-plane stiffness . 228
20.1.4 Out-of-plane stiffness . 228
20.2 Analysis and test . 229
20.2.1 General . 229
20.2.2 Analysis . 229
20.2.3 Testing . 229
20.2.4 Comparison of analysis and test values . 229
20.2.5 Composite face sheets . 230
20.3 References . 230
20.3.1 General . 230
21 Fatigue . 231
21.1 Insert fatigue life . 231
21.1.1 General . 231
21.1.2 Potting . 231
21.1.3 Honeycomb core . 231
21.2 Core local stress: Normal loads to plane . 232
21.2.1 General . 232
21.2.2 Core circular stress . 232
21.2.3 Example . 233
21.3 Load-stress sequence: Constant amplitude . 236
21.3.1 General . 236
21.3.2 Mean stress ratio . 236
21.3.3 Maximum peak load . 237
21.4 Load-stress sequence: Spectra of constant amplitude . 237
21.4.1 General . 237
21.4.2 Example . 237
21.5 Fatigue life: Constant load amplitude . 237
21.5.1 Fatigue damage . 237
21.5.2 Fatigue life . 238
21.5.3 Re-evaluation of core strength variation . 239
21.5.4 Insert fatigue life: Metallic cores . 240
21.5.5 Insert fatigue life: Non-metallic cores . 251
21.6 Fatigue damage accumulation . 252
21.7 Non-metallic core . 252
21.8 Composite face sheets . 254
21.9 References . 254
21.9.1 General . 254
21.9.2 ECSS standards . 255
22 Environmental effects . 256
22.1 Insert under thermal conditions . 256
22.1.1 General . 256
22.1.2 Mechanical loading in a thermal environment . 256
22.1.3 Mechanical loading after exposure to a thermal environment . 256
22.1.4 Mechanical loading after thermal cycling . 256
22.2 Thermal: Reduction of permissible load . 258
22.2.1 Effect on permissible loads . 258
22.2.2 Coefficient of thermal degradation . 258
22.3 Other conditions . 259
22.4 Composite face sheets . 260
22.4.1 In-plane load under thermal conditions . 260
22.5 References . 260
22.5.1 General . 260
22.5.2 ECSS standards . 260
23 Manufacturing procedures . 262
23.1 Sequence . 262
23.1.1 General . 262
23.1.2 Sandwich panels . 262
23.2 Fit inserts . 263
23.2.1 General . 263
23.2.2 Positioning . 263
23.2.3 Perforated core . 264
23.2.4 Non-perforated core . 264
23.3 Inject potting compound . 265
23.3.1 General . 265
23.3.2 Process . 266
23.3.3 Flow characteristics . 266
23.4 Cure cycle . 267
23.4.1 General . 267
23.4.2 Resin system: Shur-Lok SLE 3010 . 267
23.4.3 Potting foam: Lekutherm X227+T3 . 267
23.4.4 Other resin systems . 267
23.5 Corrective actions . 268
23.5.1 General . 268
23.5.2 Final machining . 268
23.6 Reference sample. 268
23.6.1 General .
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