':0,, .- breiikouts{ook~!~.&te 1p.a dif'..-0-'. q '~i.-".~." 1~~0{;ti::~~gh ~~;:~

Transcription

1 =--' & r ':0 Liberator trend. Remains at Large i o ;Each-bffhe thre-e.- breiikouts{ook!.&te 1p.a dif'..-0-'. kizown... weall k116}i'n.) should'v.". c. ( 1twasli6\vver the third / The " forthe --" lli"theeibj LW:e);jjtQc:$'?caDI1ities. ;;;.t"(;"."#!;i" "';"':":. B elli[of\the"'.-.':te1co11m1umcatem "'.."'.="'-"-"c-. ; y --.'. rglous:tt 2r -.:u c Jt!" IS..?;:j;i ne: -.;:; I - c c avinj;!;suspi "'i'-.'"..-"-"c tthe!; hsb ( ards nad They.+ J thi: y devices JMi-w11]f1iir ".."".;":C" tun eo f q 'i.-".." 10{;ti::gh ;:. ' ; -atetltlyche t; some- ffi-'{j"1 --a111j:e; - laccesstocentral ;.'-it:;it;- rife'nbrtsmade.;by -."s""c!:;"" -f"' "'"'-arq 'nev e riecic h e d nson!'.;; """-':i':;':'c' :. ':f1 f."".o '" was.. [i11i: " :e1l'till a lonan a. e;..'.k;.. ren ;iii1lic ;'i:;t2 1"'- e t " th / t"i?o"""''k;;"': lil';.eo r; lgad=e{i"'i:" -W" :mre.-:t:!1i "." "7 ;';"''[-tmir " :! escaped. It has. been speculated lhatguy Floating.::oncAeie... Jje ob1jioz.lsl.v had his head i1 the. Should'vE :: '"' se the '. I churnmgwateis. And once cc again b "The Liberator"had ;a clolld. th! -9$ I waterjus!w1etq that there was an inside mole behind all of the escapes but there is no supporting dence. The.FBIis attempting evi- cultently to predict when 2003 Mil\vaukee School of Engineering Concrete Cal16e Design Paper

2 Compliance Certification I John A. Knowles and other members representatives of the American Society of Civil Engineers Student Chapter at the Milwaukee School of Engineering hereby certify that to the best of our knowledge The Liberator was built in complete compliance with the 2003 Rules and Regulations of the National Concrete Canoe Competition. The registered participants from the Milwaukee School of Engineering are national student members of ASCE and they participated in the construction of the canoe which occurred within the academic year. o: < Z A '-. -Date 5""!""=1- t o Milwaukee School of Engineering ASCE Student Chapter President i/ '.::) 1--' "'--' 5./7htTO-<. "...) "" Christopher Haase Date!lI"1i :5/7!t"\ ves Date / -1b'Cf.--! / / :t / 0 3.JIh KeDecca Semmler No- Date -7?1 5" /7 Ln Marie Roscoe Date i If'j- /1/03 Adam Boucher Date -1f 1L S/T/os Bobby LaBrec Date /7/:iAU2- ' 5/7/03 ;';;;e-p:t: I vl/ l Date Page i

3 The Liberator Introduction The geometry of the canoe hull was based upon experience and boat design software to achieve the best performance in the water. The goals of the structural analysis of the canoe were to: O Determine the hull thickness based on the material properties of the tested concrete and reinforcement composite O Determine if ribs and thwarts were necessary O Ensure that the stress in the canoe was less than the stress capacity of the composite Canoe Loading Paddler weight the weight of the canoe and the resultant water pressure are the forces acting upon the canoe (Figure 1). The forces exerted by the paddlers were determined by pressure-indicating film which measured the contact surface pressure between the knee and the surface of the canoe. The weight of the canoe was determined from a three-dimensional CAD calculation. The water pressure exerted on the hull varies by its depth and was Fi2ure I: Canoe Crossdetermined by the displace- Section Loadinl! ment of the canoe in the water. Two load cases were taken into consideration with males at 190 pounds each and females at 160 pounds each (see Figures 2 and 3 for paddler locations). O Load Case 1: Two Males O Load Case 2: Two Males + Two Females Anaiysis Finite Element Analysis An elastic Finite Element Analysis (PEA) of the hull geometry using four-node shell elements was used to determine the stress in the canoe. The Modulus of Elasticity used in the analysis was 1300 ksi which was determined by testing (Figure 4 ). The external loads were modeled with distributed forces for water pressure self weight for canoe weight and spring supports in paddler knee locations. Iterative analyses were performed varying the thickness of the canoe until the stresses were less than the material capacity. The geometry of the.hull was optimized using a PEA optimization program. The results of this program showed that by adding stiffer material near the paddlers and sidewalls optimal structural performance can be achieved without adding hard-to-construct ribs and thwarts. Material stiffness was increased by adding carbon fiber tape which increased the Modulus of Elasticity (Figure 4) to 1600 ksi. Areas with the higher Modulus of Elasticity were incorporated into the PEA program. Conclusion The PEA and optimization program conclude that the creation of a 5/8" thick concrete hull and a reinforcement scheme as shown on Page 7 will provide adequate structural performance. The two maximum stress regions were shown by the analysis. In the twoperson loading case (Figure 2) a maximum stress of 652 psi was located at the gunwale. In the four-person loading case (Figure 3) a maximum stress of 478 psi was produced under the paddlers' knees. These stresses were lower than the material capacities of 775 psi and 1550 psi shown in Figure 4. Side View I Max Stress = 652 Page 1

4 The Liberator Development & Testing Introduction Based on experience and FEA the two primary failure modes in canoe design are flexure and punching shear. Concrete mix ingredients were combined with reinforcement to find the best composite for strength and constructibility. Material properties of the final composite selected were incorporated into the FEA. Reinforcement Materials considered for the reinforcement were: O Carbon fiber mesh O Steel cables O Fiberglass mesh O Carbon fiber tape O Wire mesh A decision matrix was made that considered cost weight thickness strength and alkali resistance. The strength and weight of the reinforcements were determined from manufacturer specifications. Carbon fiber mesh proved to be the strongest and lightest but was too costly to use on the entire canoe. Instead fiberglass mesh was used throughout the majority of the canoe while carbon fiber tape was used for added strength in high stress areas. Alkali resistance was verified to ensure that the reinforcement did not disintegrate when exposed to portland cement. Concrete Materials considered in the concrete mix were: Aggregates O Latex admixture O K-46 glass bubbles O Epoxy O Sand O Silica fume O Carbon fibers O Flyash O Polypropylene fibers O Portland cement Again a decision matrix was made based on finishability composite strength and weight. Finishability was highly considered because the concrete canoe surface is exposed. Mixes are compared in Composite Testing below. Composite Testing Testing the concrete mix alone was deemed unnecessary because it would not provide any useful information for the FEA. Instead 50 different concrete mix proportions were combined with reinforcement to determine the best performing composite. Flexural Testing. Concrete plate specimens (2.75" x 14" x 0.75") were made and tested according to ASTM Designation C947-99: Standard Test Method for Flexural Properties of Thin Section Glass-Fiber-Reinforced Concrete (Using Simple Beam With Third-Point Loading). This test determined the strength and Modulus of Elasticity of the compoite which were used in the FEA. The first flexural test determined that latex admixture was the strongest binder. The amount of binder was then varied and used to conduct a strength-to-density comparison (Table I). Table I: St.ren2th-to-J Mix I Description LiGht Strength (Dsi) As more binder was added to the mix the stronger heavier and more finishable the mix became. Fibers gave the concrete an undesirable finish but added strength and made the composite more ductile. The best combination of mixes and reinforcement was combined in the final composite design. Fi2ure 4: Final Composite Desil!n -Fiberglass -Fiberglass '0 200 "C c 0 "C ensitv. Oensli Mesh Reinforced Mesh w/ Carbon Fiber Tape Deflection [inches] Punching Shear. A punching shear test was conducted on a 12" x 12" x 5/8" specimen and foam was added under the loading force until the desired shear capacity was reached. This determined thickness of foam is positioned under the paddlers' knees in the saddle seat. Conclusion The final mix design consisted of a high-strength exterior surface mix with latex and a lighter more flexible interior mix with fibers (see Pages 89 and 10). The final composite design was composed of 5/8" concrete and four layers of fiberglass mesh which produced a yielding capacity of 775 psi compared to the canoe's maximum stress of 652 psi. The composite with carbon fiber tape produced a yield stress of 1550 psi and was used in high-stress areas. Combining the material capacities with the PEA results gave a safety factor of 1.2 and 2.4 respectively. y Page 2

5 The Liberator Project Management & Construction Construction Mold. The canoe form (Page 6) construction consists of the use of both a male and female mold. The benefits of this process are: O Eliminates exterior casting flaws on canoe O Reduces sanding and finishing time O Produces a practice canoe Male Mold. Sections of the canoe were created using three-dimensional CAD software were constructed from laser-cut hardboard and mounted to a steel base. The laser produced canoe sections within a tolerance of :to.oos in. Alignment holes were cut into the sections and threaded rods were used to ensure accurate alignment and spacing of the canoe sections. Polystyrene blocks were placed between the hardboard sections and cut using a hot wire to match the contour of the canoe sections. Plaster was used to create a smooth solid surface on top of the polystyrene and to stop the fiberglass used for the female form from disintegrating the polystyrene. Lastly rapid prototyped bow and stern tips were manufactured using three-dimensional CAD files in order to eliminate the guesswork of shaping them by hand. Female Mold. After the male mold was created it was sealed with shrink wrap and fiberglass was placed around it to create the female mold. Only the female mold was used in the final casting of the concrete canoe. Casting. On the casting day the following stations were established: the mixing area the casting area and the reinforcement area. All dry ingredients were prepackaged before the casting day. Once mixed the concrete was laid into the fiberglass mold. Removable plastic strips were placed inside the mold to gauge the thickness of the layers of concrete and reinforcement. Once the designated thickness was reached a layer of reinforcement was placed and then the next layer of concrete was laid on top of the reinforcement. This process continued until the desired number of layers was reached. Also during this process carbon fiber tape was placed in strategic areas designated by the principal engineer to give the canoe added strength. Finally lasercut stencils were used to cast colored concrete to give an aesthetic appeal. Curing/Finishing. A humidification tent was constructed around the canoe to allow proper curing conditions. After the 28-day curing process the fiberglass form was cut away from the concrete exposing The Liberator. The canoe was sanded using auto body pneumatic finishing tools and stained according to the Theme Committee's specifications. Project Management Organizational Structure. A design-build structure (Page 5) was organized and consisted of the principal architect principal engineer and project manager all of whom met to determine the necessary committees to successfully accomplish the project goals. The chairs of each committee were determined by interest and experience. Co-chairs were also assigned to each committee to enhance learning and participation. This structure was chosen because it enabled each member of the chapter to playa vital role in the creation and development of The Liberator. Schedule. A preliminary schedule and estimate were created in September to outline the activities and funds required for the year. The schedule was created using project management software (Page 4 ). Milestones. Completion of the hull design structural analysis determination of mix and reinforcement design completion of the formwork and casting the canoe were all major milestones. The timely completion of these milestones is crucial in the production of a high-caliber project. Critical Path. The critical path of the concrete canoe project started with the distribution of tasks continued with the completion of the canoe design and construction and concluded with the trip to the regional competition. The anticipated start and finish dates were within one to two working days of the actual dates which can be attributed to excellent project leadership. Project Safety. Worker safety was carefully taken into consideration by implementing a safety program consisting of OSHA safety standards OSHA lung capacity tests respirators and a ventilated dust area. A portfolio of MSDS sheets detailing every material used in the project was on hand in the laboratory facilities at all times. Planning and Implementation. The conception of The Liberator began with the ingenuity of the project leaders. Weekly meetings were conducted to discuss the canoe's schedule budget and design. Committee leaders presented ideas to the team and major decisions were decided by vote. Also each team member was informed of deadlines and expected workdays through for optimal efficiency. Documentation for every process was logged to ensure that valuable information would be saved for future reference. The superlative coordination of activities and outstanding efforts of the workers make The Liberator victorious. Page 3

6 The Liberator Schedule -DeSign StJuctural AnalysIs Begin of Structural Anals Resea Detenninatlon computer Anels Documentatk)n l --!--- of Force --- Completion of Structural Is Hull Design R..ea Develooment/Dranina I Completion of Hull Design [--co;;st;;;-cil;;n/d.';;;--- l FrameIMold Deslon I Construction Beoin.- - I Frame Asse I Canoe suu!!'g Fonnlno Foam Fonn Finlshin'L 188.IO6/O2105/ :=! : : i I i-" 0 09/18/02. ' I I 0 D5/23/O3 I:. -- 1M. 09/18/ / /18/02 05/11/ /18/02!!!! /16/02 10/14/02 16 D5/05/O /03 I i I 1i09/1iiiiil09/18/02 I 1 1D5.1O9/18/O2 102I03r03 1 I: ;.. r1wi/18/o2 102I1J3 I /18/02 111/21/02 I 0109/16/ /18/02110/14/ /15/O t --53I09I/O2 111/21/ /O9ii)2l I /02103 II --I /10103 Ii I 1.. :.. I Computer FIOW:.:;'a!VSis- "'""- l..'.-.! : ; : :..Y - " - I : : --: : /16/ /03 I " ' -y ' 009/16/ / ::: 12111/ /26102 I I!.::: : 'L : : : :::rrl '.'- Mix Concrete Apply Concle\e and Reinfort:;n" Cure Canoe Sanding 1 I I \ i Canoe ComDieted - CompetitIon Preparation Asseansport Box Photogreohlc Documentation -ompetitlon Materials Report COmpillnll 01 Reoort Proofin of Reoorl /O2 104/30103 I I.." 2 D4/14/OS D4/15/OS /18/02 D4/14/OS 2 D4/S0/OS /3O/OS S7.02/04/03 03/26/ / /05/ S/O6/O3 03/26/ /26/ /12/OS 05/02/03..02/12/OS /14/O3 0 05/O2/OS /30/02 D4/25/O3 3 10/25/02 10/29/ /30/02 11/15/ S/10/OS D4/25/OS i : i LJ i t:; ". i A...7! '---'"".. 1 Project Closeout /01/03 05/05/03 lij /16/02 OS/20/ /16/02 02I0SI / /09/03 I I 10105/10/ /031 I Page 4

7 Page 5

8 f..- Page 6

9 r

10 The Liberator Mixture of Proportions (Interior Mix) Mixture Desiqnation: Interior Mix ICOmDOnent Quantity (whether base or atch) lair content by volume of concrete AIR: 5.6 ICement (plain) ASTM Type: II Flyas Description: Iass- ILatex solids I Descriptio: 8-20 S8R 46.5% Solids c: m1: m2: IMass of all cementitous materials cm: 213 (1) Cement-to-cementitious materials ratio c/cm: 0.71! Aggregate 1 Base Quantity (SSD aggregates) kg/m3 IK46 qlass bubbles WSSD1: 198 ISand Polypropylene.Combined fibers W SSD2: W SSD3: I W SSDagg: ASTM C127 BSG (SSD) (unitless) Agg. Volume (m3/m3) Batch Quantity (At stock I moisture content) ka/m3 Wstk1: Wstk2: Wstk3: W stkagg: (2} Water w: 342 Volume of latex ISuperplasticizer IConcrete coloring X1: 50 X2: 556 X3: 0 Wbatch: 339 lwater from latex 27 IWater from superplasticizer IW-ater from concrete coloring [Total of free (surplus)watertrom all aggregates ITotaTWater w: 342 w: Concrete densit Water-to-cement ratio w/c: IWr-to-cementitious material w/cm: r;;;;;- 1(3) Page 8

11 The Liberator Mixture of Proportions (Exterior Mix) Mixture Designation: Exterior Mix icomponent Quantity (wnether ase or batch) - lair content by yolumoj concrete AIR: 3.3 ICement (plain) ASTM Type: II c: 662 Flyash Description: Class C m1: 189 Latex solids Description: 8-20 S8R 46.5% Solids m2: 85 Mass of all cementitous materials cm: 936 Cement-to-cementitious materials ratio c/cm: 0.71 (1) 'Aggregate K46 glass bubbles Sand Polypropylene Combined fibers Base Quantity (SSD aggregates) ASTM C127 BSG (SSD) (unitless) kg/m3 WSSD1: WSSD2: 2.75 WSSD3: O 0.91 W SSDagg: Agg. Volume {m3/m3) I Batch Quantity (At stock moisture content) kq/m3- Wstk1: 115 Wstk2: 110 Wstk3: 0 W stkagg: 225 (2) Water w: IVolume of latex! Superplasticizer Concrete coloring Water from latex Water from superplasticizer ter from concrete coloring "Total of free (surplus) water from all aggregates Total water w: 356 I Concrete deltv IWater-to-cement ratio I Water-to-cementitious material X1: X2: X3: O Wbatch: w: w/c: 0.54 w/cm: (3) Page 9

12 The Liberator Mixture of Proportions (Coloring Mix) ICement (olain) 1(1) (2) j(3)