Thursday, 2 July 2009

[week 22] final presentation

The thisis can be found on TU Delft Repository.



Tuesday, 30 June 2009

[week 21] process reflection

Between the planning made in the learning plan and reality are some differences:

week

planning

reality

February 2008

zoeken opdracht en verzamelen theorie

discussing materializing the pavilion as assignment

March 2008

kritische analyse opdracht en theorie

Analyzing case

June 2008

P1: voorlopig leerplan

P1:learning plan

Oktober 2008

vaststellen methode+eis

Determination criteria


ontwerpen en afwegen variant

Designing options

1-7 november 2008

vaststellen te onderzoeken bouwdeel

Determination building part

10-14 november 2008

terugkoppeling onderzoek naar ontwerp

Applying research in design

17-21 november 2008

ontwerp aanpassen aan knelpunten

Design adjustments to problems

24-28 november 2008

praktische uitwerking klimaat, veiligheid, pve

Integrating functional criteria

1-5 december 2008

detailleren te onderzoeken bouwdeel

Detailing building part

8-12 december 2008

berekenen te onderzoeken bouwdeel

Calculating building part

15-19 december 2008

voorbereiden voor experimentele proef

Visualising

5-9 januari 2009

P2: leerplan en voorlopig ontwerp/onderzoek

P2: shape options and conclusion




12-16 januari 2009

voorbereiden voor experimentele proef

Analyzing problem

19-23 januari 2009

bouwen experimentele proef

Three connection problems

26-30 januari 2009

uitvoeren experimentele proef

Overview design options

2-7 februari 2009

verwerken experimentele proef

Preparation mechanical testing

9-14 februari 2009

P3: plan voor generieke kennis en toepassing

Building rib variants

16-21 februari 2009

report plan for research

testing

23-28 februari 2009

making priliminary mock ups for discussion

Functional unit, Processing test results

2-7 maart 2009

presentatie P4: definitief ontwerp/onderzoek

Options with ribs

9-14 maart 2009

verwerken commentaar P4

Design of entire building

16-21 maart 2009

afmaken prototype/maquette

LCA comparison

23-28 maart 2009

voorbereiden presentatie

P3: plan for options

30 maart - 3 april '09

presentatie P5: conclusies, project en proces

methodology

6-11 april 2009


Generative tool

13-19 april 2009


materials

20-25 april 2009


material selection

27 april-1 May 2009


System design

4-9 May 2009


Report, Multi criteria

11-15 May 2009


Reflection and conclusions

18-22 May 2009


making priliminary mock ups

25-30 May 2009


presentatie P4: final research

1-6 June 2009


Strength and durability of Kenaf

8-12 June 2009


detail design

15-18 June 2009


Report, Multi criteria

22 -27 June 2009


Reflection and conclusions

29 June 2009


P5: making mock up

As can be seen in the table above, some steps have started later or took longer than foreseen. This is mainly because the design process is not linear but a cycle. There have been made several options that have been tested and processed.

The colors indicate the same kind of task. Most colors occur in both planning and reality. The bright red fields indicate decision moments that have not been planned.

[week 20] multi criteria comparison

The same functional unit requirements makes it possible to compare the system designs. System design 4 is not complying to the requirement of a thin rod package because of the bracings.

There is some uncertainty in use time, dimensions and environmental index. Especially the kenaf core construction still has some uncertainties and topics for further research.

The C2C bonus is the added value of the material next to the functional unit. Biosphere materials have the possibility of energy recovering after use.

The table below compares known variables for an end grade. Higher numbers are better. Numbers are therefore normalized with best practice =1.

name

function

Environmental index

C2C bonus

total +factor

1. technical

o

0,19

+- 10%

O

0,19

2. steel-

wood

o

0,13

+- 10%

O

0,13

3. kenaf

core tube

o

0,56

+- 10%

+

0,84

4. wood

joints

-

1,0

+- 10%

+

1

5. solid

wood

o

0,1

+- 10%

+

0,15

Because of not fitting the functional unit the wood joints are not chosen as final design.

Kenaf core tubes are the best option in total.


Thursday, 18 June 2009

[week 17] presentation

Everyone interested is invited to my presentation:

Monday, 15 June 2009

[week 19] Strength and durability of Kenaf Stressed Skin Panel extrusion

design

Agricultural fibres can be pressed or extruded to plate material. The design that is elaborated here exists of kenaf particles extruded to a tube.




Kenaf (Hibiscus cannabinus) is a fast growing fiber crop related to cotton, okra, and hibiscus. The plants, which reach heights of 2,4 to 6 meters, are harvested for their stalks from which the fiber is extracted. The fiber is used in the manufacture of industrial textiles, ropes, and twines. Kenaf is among the most widely utilized of the bast fibers. (CES EDUPACk 2009)



Harvesting of Kenaf, source: http://bridgemail.bigbridge.com.au


Panasonic has set up a plant in Malaysia to manufacture kenaf core fibre boards and export them to Japan. Kenaf core fibres are comparable to hard wood. (http://en.wikipedia.org/wiki/Hibiscus_cannabinus)



source: http://www.stramit-int.com/index.html

variables

Input

Fibre type (kenaf core)

holocellulose content (71.24%)

lignin content (23.22%)

ash content (5.93%)

Kenaf core is a product from the flax plant. The properties of resin free fibreboard are superior to wheat straw, reed, palm or meadow (Jianying Xu 2006).

Fibre length (5,5 +- 2,49mm) 1,6//8 cm

Fibre length balances between modulus of elasticity and modulus of rupture.

Fibre diameter (284 +- 136 µm)fiber width (0.82–1.73 mm) cell wall thickness (3.36–5.25 lm) lumen diameter (5.82–10.39 lm)

Resin type (none)

Most fibre boards contain UF or MDI glues. Sometimes the natural lignin in the fibres can provide the necessary bonding.

Resin content (0 %)

Steam-injection during pressure -> yes

Steam injection gives better properties to the board (widyorini2005)

Pressure (0,6 MPa) 0,6/0,8

This results in a density (500 kg/m3). 300

Time of cooking (10min) 20/30

Cooking of fibres before bonding gives higher internal bonding and less thickness swelling.

Test conditions

Relative humidity (10-90%)

Outcomes

Modulus of Elasticity MOE (2,3 ± 0,1 MPa)

Modulus of Rupture MOR (19.4 ± 2,0 MPa)

Internal Bond IB (0,24 ± 0,04 MPa)

Thickness Swelling TS (18 ± 1 %)

design strength performance

height 350 mm

width 1200 mm

flange thickness 28 mm

web thickness 28 mm

Elastic deformation

MOE of 2,3 MPa results in a vertical deformation of the roof of 5/384*1,7*9000^4/ (2400*2*28*1200*175^2)= 29 mm. This is within the tolerance of 45 mm.

Long term deformation

Long term deformation caused by creep is not investigated yet. MDF shows a a comparable creep behaviour that could be studied. Conclusions from this study (Fernandez1998) are that the stress should remain below 20% of MOR to avoid rupture. Also a high relative humidity should be avoided.

Stressed Skin Panel tests with wood webs and OSB flanges showed that tests on deformation and Modulus of Elasticity showed similar outcomes (Kliger 1995).

bending strength

With a MOR of 17,4 MPa and a bending resistance of 2,1 *10^9 mm4 is a bending moment of 204 kNm possible. The designed load of 21 kNm is below this.

compression strength

The roof leans on the walls. The weight per half roof element is 70*4,5*1,2=380 kg. The surface of a wall column is 2 sides*260 depth*28 thickness=. This means that the compression force is 380*9,81/14560=0,26 N/mm2. This is below the maximum compression force of 17,4 N/mm2.

design moisture performance

Moisture and temperature conditions are calculated for worse case scenario.

inside temperature 20 oC

inside relative humidity 60%

outside temperature -10 oC

outside relative humidity 50%


To control relative humidity during high outside relative humidity, a vapour barrier around the construction could be helpful. Food industry uses bee wax coatings to improve the freshness duration.


The same wax layer on the inside and outside will trap the moisture with condensation as result.

A solution is to apply a thicker wax layer on the inside to lower the vapour pressure in the construction and insulation.


Rtot=0,04+0,06+0,06+5,00+0,06+0,10+0,13=5,45 m2K/W

Q=30/5,45=5,4 W/ m2


Tis= 20-0,13*5,5=19,3 oC -> Pio.max=2240 Ps

Tloam= 20-(0,13+0,1)*5,5=18,7 oC -> Ploam.max=2175 Ps

Twax= 20-(0,13+0,1+0)*5,5=18,7 oC -> Pwax.max=2175 Ps

Tflange= 20-(0,13+0,1+0,06)*5,5=18,4 oC -> Pweb.max=2117 Ps

Tstraw= 20-(0,13+0,1+0,06+5)*5,5= -9,1 oC -> Pweb.max=281 Ps

Tupperflange= -10+(0,04+0,06+0)*5,5= -9,5 oC -> Pweb.max=271 Ps

Tes= -10+0,04*5,5= -9,8 oC -> Pweb.max=264 Ps

Figure, Glazer diagram of vapour pressure in construction.


references

Jianying Xu. Development of binderless fiberboard from kenaf core, Journal of Wood Science, springer: Japan, 2006.


Kliger, IR, Pellicane, PJ. Prediction of Creep Properties of Chipboard Used in Stressed-Skin Panels Research scientist, Journal of Testing and Evaluation
Volume 23, Issue 6 , Chalmers University of Technology, 1995.


Ragil Widyorini, Jianying Xu, Takashi Watanabe and Shuichi Kawai. Chemical changes in steam-pressed kenaf core binderless particleboard, Journal of Wood Science. Springer: Japan 2005.


Wednesday, 10 June 2009

[week 18] extruded kenaf design

An animation of the stressed skin panel design:

Tuesday, 19 May 2009