Environmentally Neutral Engineering Composites for Boats and Aircrafts

TRADITIONAL ENGINEERING MATERIALS

Steel, Aluminum, Brass, Bronzes, Plastics, Polymer Composites and Wood are the most used traditional engineering materials. These have certain properties as follows: (CLICK on the TABLE to ENLARGE have a better View)

Certain Traditional Engineering Materials properties

Certain Derived Properties of Composites in Fibers, Compared with Steel

Fiber (40% uni-directional)	Tensile Strength	Sp.wt	Sp. Tensile Strength	Tensile Modulus	Eq Wt Section	Eq. Wt Rigidity Modulus	Cost Factor
	(MPa)	(kg/m3)	(m)	(GPa)	(cm) Carbon Steel = 1 cm	(Kg-m2)	(Rs/ Kg)
Bamboo	293	600	48833	18.32	13.08	3416	250
Bamboo-Glass	350	703	49786	18.23	11.16	2111	255
Hybrid Bamboo1	440	688	63953	22.85	11.4	2282	740
Hybrid Bamboo2	438.2	695	63050	27.09	11.29	3248	990
E-Glass	816.8	1474	55413	18.91	5.32	237.27	270
S-Glass	1104	1455	75876	23.16	5.39	302.22	510
Carbon Fiber	1222	1336	91467	74.95	5.87	1263	3210
Kevlar 49	1298	1243	104424	45.27	6.31	947.8	2210
Boron	946.5	1467	64519	92.94	5.35	1186	3810
High tensile Steel	4000	7900	50632	210	0.99	16.98	250
Low Carbon steel	400	7850	5095	210	1	17.5	60

Comparative Design Advantage of Hybrid Bamboo Composites:

In order that we are able to arrive at “optimum” engineered material system for a particular design need, we shall compare the “Rigidity factor” based on Low Carbon Steel (which is the standard structural engineering material)

The average thickness of Steel sheet material needed for the hull of a small 20 ft Dinghy that needs to be “seaworthy’ is 6 mm. The various thickness factors for the Composites (based on equivalent Rigidity factor) are presented below:

Fiber (40% uni-directional)	Tensile Strength	Sp.wt	Sp. Tensile Strength	Engineered Section	Wt per Sq m	Rigidity Modulus	Fabrication Cost Factor
	(MPa)	(kg/m3)	(m)	(cm)	Kg	(Kg-m2)	(Rs/ Sq m)
Low Carbon steel	400	7850	5095	0.6	47	3.78	5640
Bamboo (40%)	293	600	48833	1.36	8.16	3.84	3060
Bamboo-Glass	350	703	49786	1.36	9.56	3.82	3657
Hybrid Bamboo1	440	688	63953	1.26	8.67	3.8	7700
Hybrid Bamboo2	438.2	695	63050	1.2	8.34	3.9	9908
Kevlar 49	1298	1243	104424	1.01	13.11	3.88	33319

 It is noted that we could engineer superior structures using both 40% bamboo composite and bamboo-glass composites. The cost factors would be lesser than that of Low carbon steel structure, even at 50% excess thickness levels in the Bamboo composite structures. That would mean far superior Strength-Rigidity factors in the resultant engineered systems. See the Table below:

Fiber (40% uni-directional)	Tensile Strength	Sp.wt	Sp. Tensile Strength	Engineered Section	Wt per Sq m	Rigidity Modulus	Fabrication Cost Factor
	(MPa)	(kg/m3)	(m)	(cm)	Kg	(Kg-m2)	(Rs/ Sq m)
Low Carbon steel	400	7850	5095	0.6	47	3.78	5640
Bamboo (40%)	293	600	48833	2.04	12.24	12.96	4590
Bamboo-Glass	350	703	49786	2.04	14.34	12.89	5485

It is further noted that even at double the “minimum thickness” for “steel equivalent” Rigidity factor, the weight factor is only about one-fourth of steel … allowing us to have greater Strength-Rigidity-Economics

For more details on the subject of STRENGTH, RIGIDITY and related Factors, please visit the blog:

http://cr4.globalspec.com/comment/752322/Re-Optimized-Engineering-Materials-Through-Cleantech

Bamboo-Composite Molded Boat/ Dinghy (Click to Enlarge)

Please see the following blogs on this subject for more details:

1. http://cr4.globalspec.com/comment/750225/Re-Optimized-Engineering-Materials-Through-Cleantech

2. http://cr4.globalspec.com/comment/754912/Re-Optimized-Engineering-Materials-Through-Cleantech

We are now looking at the possibility of Designing and constructing a Lightweight AIRCRAFT (Two-Seater) using Hybrid Bamboo Composites. Please see here:

http://cr4.globalspec.com/comment/756431/Re-Optimized-Engineering-Materials-Through-Cleantech

Main Structure Syatems in a Lightweight Aircraft