The Gougeon Brothers on Boat Construction - WEST SYSTEM Epoxy

More documents

Recommendations

Info

386 Appendices Maximum stress (x 1000 psi N-Cycles Figure C-10 Primary fatigue properties of wood. Shearing loads can be very high in wind turbine blades. Because of this, the shearing capability of wood/epoxy laminates was carefully evaluated. Of special concern were bonded joints with defects and gaps up to .25" (6mm) that were filled with a thickened 105/206 WEST SYSTEM adhesive. This kind of joint will have some stress concentrations because of the difference in shear modulus between wood and adhesive. (Douglas fir is 125,000, and 105/206 epoxy is 375,000.) It is also difficult to make this kind of joint without small voids Side View Centered Wedge Figure C-11 Longitudinal wedge joint test specimen details. or air bubbles in the adhesive. <strong>The</strong> cost of these defects to design allowables needed to be evaluated. Figure C- 11 shows three different kinds of joint defects that were tested in fatigue. <strong>The</strong> object of this program was to simulate worst-case results that could occur under typical manufacturing conditions. All of the I-beam samples were tested in shear, using a three-point bending fixture that supported the 30"-long sample between two points 24" apart. Load was then applied at the center of the 24" dimension. Eighteen specimens were tested, with six representing each joint category. All testing was performed at a stress ratio of R = 0.1 at varying load levels to develop S-N curves. <strong>The</strong> combined results of this test series are plotted in Figure C-12 and, even with a limited sample population, some remarkable results were produced. <strong>The</strong> notably shallow trend line suggests the shear fatigue capability of wood composite with defects is unusually good, especially when compared to the already excellent trend lines of the primary fatigue properties of tension and compression. Most important is the apparent insensitivity of the bonded joints, which are defects themselves, to major defects. <strong>The</strong> “Type 2 Defect” test samples (half-inch square nylon chips placed at two-inch intervals), in Wedge Detail Shifted Wedge
<strong>The</strong> <strong>Gougeon</strong> <strong>Brothers</strong> On Boat Construction 387 Log 10 S Figure C-12 S-N Diagram. Longitudinal wedge joint, shear stress, three-point bending tests with Douglas fir/epoxy laminate at room temperature. (R=0.1, 12% M.C.) Shear Stress (x 100 psi) particular, performed better on average than the ideal “centered wedge” series test sample. All test specimens displayed shear failure in the wood veneer area adjacent to the bond line. <strong>The</strong> induced defects (nylon squares) within the bond line only occasionally acted as crack initiators, with cracks developing in the test sample well before failure occurred. This initial crack generation, however, did not appear to be related to performance, for samples with defect-generated cracks performed just as well as regular samples with no cracks, further illustrating the ability of wood to live in fatigue with serious defects. No failure occurred in the bond lines or within the WEST SYSTEM epoxy adhesive itself, even at the .25"thick gap joints. This was reassuring evidence that thick bond lines can be trusted in high cycle fatigue conditions. This feature results from the ability of the epoxy itself to withstand long-term fatigue loading. Another important secondary failure mode within wood structures is perpendicular-to-grain tension fatigue. When wood structures are created by laminating rotarypeeled veneers, with all wood fiber aiming the same direction, two cross-grain dimensions result: (1) through-the-thickness (radial) cross-grain, perpendicular to the plane of the laminations, and (2) edge-to-edge (tangential) cross-grain, parallel to the plane of the laminations. (See again Figure C-8). Stress (x100 psi) Cycles Cycles Figure C-13 Tangential Fatigue. <strong>The</strong> static, tangential cross-grain tension capability of Douglas fir laminate is only 500 psi, and Figure C-13 shows this capability degrading to about 300 psi when approaching one million (106 ) fatigue cycles. This was the first time cross-grain tension had ever been tested in fatigue. <strong>The</strong> limited data that was generated, when extrapolated to 107 cycles, suggests that only about 75 psi is available for long-term use. While this may be a conservative interpretation, legitimate concern is raised over this “physical property” weakness. Designers should be extra cautious when dealing with cross-grain tension loads in their structures. Tangential cross-grain compression strength was also tested, and results suggest a typical material degradation with increasing cycles (see Figure C-13). In our experience, this mode of failure would be unusual for most marine structures. A more critical concern is the radial cross-grain tensile fatigue strength. It is nearly impossible to design large wood structures that do not incur at least some radial cross-grain tensile stress. Until recently, the potential for through-the-thickness failures of plywood due to tensile fatigue was little understood. A significant advance took place in the late 1980s as a result of a dedicated GBI research program underwritten by the U.S. Department of Energy (DOE). <strong>The</strong> study was a breakthrough, since innovative specimen design and
Page 1:
The Gougeo
Page 4 and 5:
Gougeon Br
Page 6 and 7:
iv Table of Content Getting Started
Page 8 and 9:
vi Table of Content Chapter 17 Mold
Page 10 and 11:
viii Table of Content Later Product
Page 12 and 13:
x Preface The brie
Page 14 and 15:
xii Table of Content
Page 16 and 17:
2 Introduction With the help of fri
Page 18 and 19:
4 Introduction
Page 21 and 22:
Modern Wood/Epoxy Composite Boatbui
Page 23 and 24:
Chapter 2 - Modern Wood/Epoxy Compo
Page 25 and 26:
Wood as a Structural Material CHAPT
Page 27 and 28:
Chapter 3 - Wood as a Structural Ma
Page 29 and 30:
Page 31 and 32:
Page 33 and 34:
Page 35 and 36:
Page 37 and 38:
Page 39 and 40:
WEST SYSTEM ® Products This chapte
Page 41 and 42:
Chapter 4 - WEST SYSTEM ® Products
Page 43 and 44:
Page 45 and 46:
Page 47 and 48:
Page 49 and 50:
Hull Construction Techniques— An
Page 51 and 52:
Chapter 5 - Hull Construction Techn
Page 53 and 54:
Page 55 and 56:
Page 57:
Getting Started Chapter 6 Before Yo
Page 60 and 61:
46 Getting Started Finally, should
Page 62 and 63:
48 Getting Started Designers’ fee
Page 64 and 65:
50 Getting Started
Page 66 and 67:
52 Getting Started Material Price/b
Page 68 and 69:
54 Getting Started between layers o
Page 70 and 71:
56 Getting Started mast; sails and
Page 72 and 73:
58 Getting Started
Page 74 and 75:
60 Getting Started and it is import
Page 76 and 77:
62 Getting Started necessity. We al
Page 78 and 79:
64 Getting Started Grit refers to t
Page 80 and 81:
66 Getting Started An efficient flo
Page 82 and 83:
68 Getting Started Ridge Pole Frame
Page 84 and 85:
70 Getting Started
Page 86 and 87:
72 Getting Started unimproved lumbe
Page 88 and 89:
74 Getting Started If it is not yet
Page 90 and 91:
76 Getting Started chapters, we adv
Page 92 and 93:
78 Getting Started
Page 94 and 95:
80 Getting Started The</str
Page 96 and 97:
82 Getting Started cures quickly to
Page 98 and 99:
84 Getting Started Evap. Rate LEL2
Page 100 and 101:
86 Getting Started 4. Use wet, rath
Page 102 and 103:
88 Getting Started
Page 105 and 106:
Laminating and Bonding Techniques <
Page 107 and 108:
Chapter 11 - Laminating and Bonding
Page 109 and 110:
Page 111 and 112:
Page 113 and 114:
Page 115 and 116:
Page 117 and 118:
Page 119 and 120:
Page 121 and 122:
Scarfing Scarfing remains an essent
Page 123 and 124:
Chapter 12 - Scarfing 109 and used
Page 125 and 126:
Chapter 12 - Scarfing 111 Productio
Page 127 and 128:
Chapter 12 - Scarfing 113 Figure 12
Page 129 and 130:
Chapter 12 - Scarfing 115 Figure 12
Page 131 and 132:
Chapter 12 - Scarfing 117 bevels on
Page 133 and 134:
Synthetic Fibers and WEST SYSTEM ®
Page 135 and 136:
Chapter 13 - Synthetic Fibers and W
Page 137 and 138:
Page 139 and 140:
Page 141 and 142:
Page 143 and 144:
Hardware Bonding As stated earlier
Page 145 and 146:
Chapter 14 - Hardware Bonding 131 s
Page 147 and 148:
Chapter 14 - Hardware Bonding 133 t
Page 149 and 150:
Chapter 14 - Hardware Bonding 135 A
Page 151 and 152:
Chapter 14 - Hardware Bonding 137 F
Page 153 and 154:
Chapter 14 - Hardware Bonding 139 e
Page 155 and 156:
Chapter 14 - Hardware Bonding 141 F
Page 157 and 158:
Chapter 14 - Hardware Bonding 143 W
Page 159 and 160:
Chapter 14 - Hardware Bonding 145 a
Page 161 and 162:
Chapter 14 - Hardware Bonding 147 W
Page 163 and 164:
Chapter 14 - Hardware Bonding 149 K
Page 165 and 166:
Coating and Finishing Broadly, the
Page 167 and 168:
Chapter 15 - Coating and Finishing
Page 169 and 170:
Page 171 and 172:
Page 173 and 174:
Page 175 and 176:
Page 177:
First Production Steps Chapter 16 L
Page 180 and 181:
166 First Production Steps Hull Lin
Page 182 and 183:
168 First Production Steps Figure 1
Page 184 and 185:
170 First Production Steps 1" X 4"
Page 186 and 187:
172 First Production Steps After ch
Page 188 and 189:
174 First Production Steps did the
Page 190 and 191:
176 First Production Steps stem or
Page 192 and 193:
Page 194 and 195:
180 First Production Steps case you
Page 196 and 197:
182 First Production Steps curve th
Page 198 and 199:
184 First Production Steps Mark the
Page 200 and 201:
186 First Production Steps
Page 202 and 203:
188 First Production Steps will be
Page 204 and 205:
190 First Production Steps Notches
Page 206 and 207:
192 First Production Steps image an
Page 208 and 209:
194 First Production Steps probably
Page 210 and 211:
Page 212 and 213:
Page 214 and 215:
Page 216 and 217:
202 First Production Steps Setting
Page 218 and 219:
204 First Production Steps To detec
Page 220 and 221:
206 First Production Steps Beveling
Page 222 and 223:
208 First Production Steps Section
Page 224 and 225:
210 First Production Steps Stem lam
Page 226 and 227:
Page 228 and 229:
Page 230 and 231:
216 First Production Steps Keel Fai
Page 232 and 233:
Page 235 and 236:
Building a Mold or Plug A mold is a
Page 237 and 238:
Chapter 20 - Building a Mold or Plu
Page 239 and 240:
Page 241 and 242:
Page 243 and 244:
Laminating Veneer Over a Mold or Pl
Page 245 and 246:
Chapter 21 - Laminating Veneer Over
Page 247 and 248:
Page 249 and 250:
Page 251 and 252:
Page 253 and 254:
Page 255 and 256:
Page 257 and 258:
Page 259 and 260:
Page 261 and 262:
Page 263 and 264:
Stringer-Frame Construction While s
Page 265 and 266:
Chapter 22 - Stringer-Frame Constru
Page 267 and 268:
Page 269 and 270:
Page 271 and 272:
Page 273 and 274:
Page 275 and 276:
Page 277 and 278:
Page 279 and 280:
Strip Plank Laminated Veneer and St
Page 281 and 282:
Chapter 23 - Strip Plank Laminated
Page 283 and 284:
Page 285 and 286:
Page 287 and 288:
Page 289 and 290:
Page 291 and 292:
Page 293 and 294:
Page 295 and 296:
Hard Chine Plywood Construction A s
Page 297 and 298:
Chapter 24 - Hard Chine Plywood Con
Page 299 and 300:
Page 301 and 302:
Page 303 and 304:
Page 305 and 306:
Page 307 and 308:
Compounded Plywood Construction Mos
Page 309 and 310:
Chapter 25 - Compounded Plywood Con
Page 311 and 312:
Page 313 and 314:
Page 315 and 316:
Page 317 and 318:
Page 319 and 320:
Page 321 and 322:
Page 323 and 324:
Page 325 and 326:
Page 327 and 328:
Page 329:
Later Production Steps Chapter 26 I
Page 332 and 333:
318 Later Production Steps Figure 2
Page 334 and 335:
Page 336 and 337:
322 Later Production Steps Material
Page 338 and 339:
324 Later Production Steps Bulkhead
Page 340 and 341:
326 Later Production Steps Teak ven
Page 342 and 343:
328 Later Production Steps fuel tan
Page 344 and 345:
330 Later Production Steps to the s
Page 346 and 347:
332 Later Production Steps they are
Page 348 and 349:
Page 350 and 351: 336 Later Production Steps
Page 352 and 353: 338 Later Production Steps Preparin
Page 354 and 355: 340 Later Production Steps A semici
Page 356 and 357: 342 Later Production Steps Figure 2
Page 360 and 361: 346 Later Production Steps Staple p
Page 362 and 363: 348 Later Production Steps After we
Page 366 and 367: 352 Later Production Steps Flat saw
Page 371 and 372: Review of Basic Techniques for Usin
Page 373 and 374: The Gougeo
Page 393 and 394: Fatigue Aspects of Epoxies and Wood
Page 399: The Gougeo
Page 411 and 412: Selected Bibliography While the fol
show all

The Gougeon Brothers on Boat Construction - WEST SYSTEM Epoxy

Create successful ePaper yourself

Delete template?

Save as template?