Analyzing plastic, in the context you've provided, could refer to various aspects such as the environmental impact of plastic, chemical composition, recycling methods, or the societal implications of plastic use. Due to the broad nature of the topic, I'll provide an overview that covers some of these aspects within the word limit.
### Introduction (Approx. 300 words)
Introduce the importance and ubiquity of plastic in modern society. Highlight its versatile applications, durability, and widespread use. Acknowledge the environmental concerns associated with plastic pollution and the need for comprehensive analysis.
### Chemical Composition of Plastic (Approx. 500 words)
Explain the basic chemical structure of plastic, discussing common types such as polyethylene, polypropylene, PVC, and PET. Detail the synthesis processes and how variations in chemical composition contribute to different physical properties of plastics.
### Environmental Impact (Approx. 700 words)
Discuss the environmental consequences of plastic, covering topics such as pollution, wildlife impact, and the challenges of plastic waste management. Explore the longevity of plastic in the environment, emphasizing the need for sustainable solutions.
### Plastic Recycling Methods (Approx. 500 words)
Examine various plastic recycling methods, including mechanical recycling, chemical recycling, and upcycling. Highlight the advantages and challenges associated with each method. Discuss the importance of recycling in mitigating environmental impact.
### Biodegradable and Bio-Based Plastics (Approx. 300 words)
Introduce biodegradable and bio-based plastics as potential alternatives to traditional plastics. Discuss their environmental benefits and limitations, addressing factors such as decomposition rates and resource sustainability.
### Societal Implications (Approx. 300 words)
Explore the societal implications of plastic use, including its economic importance, convenience, and impact on consumer behavior. Discuss the role of industry and government in shaping plastic consumption patterns.
### Regulations and Policies (Approx. 300 words)
Examine international and national regulations aimed at managing plastic use and mitigating environmental harm. Discuss the effectiveness of these policies and potential areas for improvement.
### Innovations and Future Trends (Approx. 300 words)
Highlight recent innovations in plastic alternatives, recycling technologies, and sustainable packaging. Discuss ongoing research and potential future trends that may reshape the plastic landscape.
### Case Studies (Approx. 300 words)
Present case studies or examples of successful initiatives or companies that have implemented sustainable practices related to plastic use. Showcase real-world examples of positive impact.
### Conclusion (Approx. 200 words)
Summarize key findings and arguments from the analysis. Emphasize the importance of a comprehensive approach to addressing the challenges posed by plasti
7. Formation of Plastic Hinge
Plastic hinge is a zone of Yielding
due to plastification of section in
flexural member
8. Ratio of Ultimate to Yield Load: Shape Factor
The bending moment at the center of the beam 4
c
M PL
Thus, the load corresponding to first yielding is
4
4
Y Y
C Y Y
P L M
M M P
L
Collapse will occur when the plastic hinge will form at the center, making the
structure into a mechanism. The collapse load is then
4
4
u P
C P u
P L M
M M P
L
The ratio of the collapse to the Yield load is then
4
4
p p p y p
u
f
y y y e y y
M L M Z Z
P
S
P M L M Z Z
Where p e
Z ,Z the plastic and elastic section modulus and their ratio are is referred
as the Shape Factor
f
S
16. Plastic Analysis of Portal Frame
Methods of Plastic Analysis
1. Static method or Equilibrium method
Collapse load is determined on the basis of collapse bending moment diagram.
This is also called Lower Bound Method as the collapse load estimates would be
always less than or equal to the actual collapse load
2. Kinematic method or Mechanism method or Virtual work method
Work performed by the external loads is equated to the internal work by the
plastic hinge formation. Load determined by assuming any mechanism will
always be greater than or equal to the actual collapse load.
Out of alternative collapse mechanism, the mechanism is one for which loading is
minimum. This is called the Upper Bound Method
21. Plastic Analysis ~ Redistribution of Moment
1
2
2 2
16
U
P P P
P
U
W
L
M M M L( )
L
M
W
L
From plastic mechanism analysis
The ratio of the ultimate load to the first yield load becomes
4
1 33
3
U P
y y
W M
. Shape factor
W M
Thus, the structure would carry an increased load of 1.33S
i.e for a I section it would be almost 1.33x1.15=1.53 i.e. a
50 percent increase in the ultimate load capacity of the beam
