Bathtub Project Composites Ahmedawad
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Transcript of Bathtub Project Composites Ahmedawad
Selecting the Right Bath Tub
• RULE 1. First determine the exact
dimensions of the space where the tub will
be placed and then consider the types of
installations that could fit into that area.
• RULE 2. Investigate the advantages and
disadvantages of commonly used bathtub
materials to determine which will work best
for you.
• RULE 3. Find a bath that is a comfortable
fit for the person who will use it the most.
RULE 4. Consider quality first and price
second.
Requirement
1. corrosion resistance
2. tough material
3. temp. adaptation
4. Wear Resistance
5. high strength
Raw Materials
• Cast Iron
The metal base for bathtubs is made of gray
cast iron (containing carbon, silicon,
manganese, phosphorus, and sulfur),
titanium steel, zero carbon steel, or partially
decarburized steel. These compositions
have been specially designed for enameling.
• Porcelain on steel
The tub is stamped from a thin sheet of
steel, then finished with a layer of porcelain
enamel. These tubs are durable and easy to
clean. The finish is resistant to most
common chemicals, and retains its gloss for
a long time
• Composites
Toughness, low cost, light weight, ease of
installation, and a finish that can be repaired
• Polymer Matrix Composite
FRP composites can be designed with very
high strength-to-weight and modulus-to-
weight ratios
Matrix properties
Tensile strength 85 N/mm²
Tensile Modulus 10,500 N/mm²
Elongation at break 0.8%
Flexural strength 112 N/mm²
Flexural Modulus 10,000 N/mm²
Compressive Strength 190 N/mm²
Coefficient of linear thermal expansion 34 10-6
Fiber Properties
Material: E-Glass Fibre
Composition: 54%SiO2-15%Al2O3-12%CaO
Property Minimum
Value (S.I.)
Maximum Value
(S.I.)
Units (S.I.)
Density 2.55 2.6 Mg/m3
Fracture Toughness 0.5 1 MPa.m1/2
Hardness 3000 6000 MPa
Poisson's Ratio 0.21 0.23
Tensile Strength 1950 2050 MPa
Young's Modulus 72 85 GPa
Maximum Service Temperature 620 630 K
Minimum Service Temperature 0 0 K
Resistivity 1e+022 1e+023 10-8 ohm.m
• Two processes called hand lay-up and
spray lay-up are used to make fiberglass
bathtubs.
Hand lay-up is a method in which
successive plies of reinforcing material or
resin-impregnated reinforcement are
positioned in a mold by hand. Cure occurs at
room temperature with no applied pressure
The spray lay-up process is faster than hand
lay-up and involves feeding a stream of
chopped fibers into a spray of liquid plastic
in a mold cavity.
• The direction of the fibers is random and
the process is usually automated. After
lay-up is completed, the plastic must
solidify or cure in a reasonable time at
room temperature, which occurs via
chemical reactions.
𝑙𝑐 =𝜎𝑓∗𝑑
2 𝜏𝑐
• 𝜏𝑐 =150
2= 75 𝑀𝑃𝑎
• 𝜎𝑓∗ = 2000 𝑀𝑃𝑎
• 𝑑 = 20 𝜇𝑚
𝑙𝑐 =2000 × 20
2 × 75= 266.6 𝜇𝑚
• 𝑙 = 50𝑚𝑚 > 15 𝑙𝑐
class 20 gray iron
Tensile Strength Ultimate152 MPa, or 22.0
103 psi
Hardness Brinell 156
Tensile Strength Yield (Proof) 98 MPa, or 14
103 psi
Specific gravity 7.03 - 7.13
𝑆𝑝𝑒𝑐𝑖𝑓𝑖𝑐 𝑠𝑡𝑟𝑒𝑛𝑔𝑡ℎ =152
7.03= 21.33 𝑀𝑃𝑎
𝜎𝑐𝑙∗ = 𝜎′𝑚 1 − 𝑣𝑓 + 𝜎𝑓
∗𝑣𝑓
• 450 = 150 1 − 𝑣𝑓 + 2000 × 𝑣𝑓
• 𝑣𝑓 = 0.162 = 16%
𝛿𝑐 = 𝛿𝑓𝑣𝑓 + 𝛿𝑚𝑣𝑚𝛿𝑢 = 2.58 × 0.16 + 1.25 × 1 − 0.16 = 1.46
𝑐𝑜𝑚𝑝𝑜𝑠𝑖𝑡𝑒 𝑆𝑝𝑒𝑐𝑖𝑓𝑖𝑐 𝑠𝑡𝑟𝑒𝑛𝑔𝑡ℎ =450
1.46= 308.22 𝑀𝑃𝑎