Structural Optimization-Simulated annealing

Structural Optimization
Lecturer:
Prof. Dr. Nildem TAYŞİ
Simulated Annealing (SA)
May 2023

Optimization
Search
Techniques
• Global
• It attempts to find the global minima or
maxima of a function or a set of functions
on a given set. It is usually described as a
minimization problem because the
maximization of the real-valued
function is equivalent to the minimization
of the function .
• Local
• It involves finding the optimal solution
for a specific region of the search space.
•

What is
Simulated
Annealing ?
•SA is a global optimization technique.
•SA distinguishes between different local
optima.

Some of Areas of
Using Simulated
Annealing
• Engineering Design
• Travel Planning and Route Optimization
• Image and Signal Processing

Simulated
Annealing
and Civil
Engineering
Some specific areas in civil engineering where
simulated annealing can be used:
• Construction Site Layout Planning
• Traffic Signal Optimization
• Urban Planning
• Water Distribution System Design
• Geotechnical Engineering
• Resource Allocation and Scheduling

How Simulated Annealing Can Assist in Optimizing The
Layout of Construction Sites.
1. Objective Definition: The first step is to define the objective of the optimization.
2. Initial Configuration: SA starts with an initial configuration of the construction site layout. It
represents the starting point for the optimization process.
3. Neighborhood Generation: SA explores the solution space by generating neighboring
configurations from the current layout.
4. Energy Evaluation: Each generated neighbor is evaluated using an objective function that
quantifies its fitness with respect to the optimization objective.

5. Acceptance Criteria: SA employs a probabilistic acceptance criterion to
determine whether to accept or reject a neighbor. Initially, neighbors with better
fitness are always accepted.
6. Cooling Schedule: The cooling schedule determines how the acceptance criteria
become stricter over time, gradually converging towards a global optimum.
7. Termination Condition: The optimization process continues until a termination
condition is met. This condition can be based on reaching a maximum number of
iterations, achieving a desired fitness level, or the convergence of the solution.

Case Study
• To optimize the dynamic reliability of engineering project, first of all, the author analyzed factors
which affected construction quality, including the human condition, methods, machinery, and materials.
• Obtain the weights of various affecting factors by gray relational degree and determined the reliability
improvement feasible index (RIFI).
• For quality, first, the system reliability optimization model is established. Secondly, a cost function is
established to analyze the changing trend of reliability in different reliability improvement feasible index (RIFI)
conditions.
• This study used the adaptive simulated annealing algorithm and produced new creation, it computed the
difference of the objective function, and then it accepted or abandoned in the process until found the optimal
solution which most closed to target.

Reliability Analysis on Civil Engineering Project Based on
SA
• In a civil engineering project, managers consider not only the cost and
time, but also the quality and reliability. Civil engineering project
reliability analysis has become an essential part of the construction
process. The reliability of the civil engineering project can be affected
by many factors that are dynamic change.

Some Factors
Affecting
Quality
1. Human factors : Human influence is a very
important factor in the project, it involves every
stage of the project and affects other factors.
2. Material factors : In the construction engineering
project, materials, mainly involve all kinds of
engineering materials, prefabricated
parts, components, finished products and semi-
finished products.
3. Method factors : If there are incorrect or improper
construction methods in the construction
organization arrangement it's likely to
cause project quality problems.
4. Mechanical factors : The control of construction
machinery quality has great effect on time quality
and safety of civil engineering projects.

Calculating The Weights of Some Factors Affecting Quality
This study adopts the gray correlation method to gain weight matrix in this section,
then gets the similarity coefficient, determines the deviation degree, difference of
sequence and the gray correlation coefficient, the gray correlation degree, finally the
study normalizes the weight affecting quality.

Evaluation Matrix Evaluation Weight Matrix

Then we calculate the similarity coefficient by the formula:
The similarity matrix can be obtained as follows:

Then we calculate the deviation. We get: p = (0.0328, 0.000,
0.0080, 0.0279). Experts’ assessment deviation values that not
exceed 5% are considered valid; we judge the value p < 0.05,
so we consider expert evaluation results to be valid. After that
we calculate the difference of sequence and the gray
correlation coefficient.

Calculating The Difference of Sequence

Calculating The Gray Correlation Coefficient
This Photo by Unknown author is licensed under CC BY-SA.

Calculating The Gray Correlation Degree
This Photo by Unknown author is licensed under CC BY.
The g4j can be calculated as g4j = [0.61, 0.653, 0.703, 1] (j = 1, 2,
3,4). After normalized, the weight can be obtained: [W1, W2, W3,
W4,] = [0.206, 0.220, 0.237, 0.337].

Reliability Improvement Feasible Index
(RIFI)
This Photo by Unknown author is licensed under CC BY.

Establishing The Models
Ti: Expenditures
C: Lowest cost
Li: the minimum reliability value
that is 0.5.
Ui: The highest reliability value that
is 0.95.

Thank You
Prepared by :
Rouna Hami
220000888090
This Photo by Unknown author is licensed under CC BY-SA.

Structural Optimization-Simulated annealing

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