146
Chapter 3
their
Functional constraints are factors which engineers have studied in
undergraduate years and dealt with during career.
The last of the constraints is the regional constraint.
C. Regional Constraints
These are the physical limitations
1. Number of men in a shop
2. Gross weight of an aircraft not to exceed the design weight of the
runway
3. Truck widths less than one lane of a highway
These generally state that a parameter must be less or greater than a
stated number. The design criterion most engineers use are the equations
taught in undergraduate course work which are called functional constraints. Then to fabricate the design, vendors are selected and the lowest
cost or criterion function to fabricate is selected. The maximum sizes or
limitations on the design are regional constraints which for the most part
are common sense. However, when optimizing with a computer or
employing an analyst all of the above criterion function, functional constraints, and regional constraints must be stated as clearly as possible.
The first solution will show if the equations are not constrained by giving
answers like infinity, zero, or a negative dimension (all real values greater
than zero positive). Various industries optimize differently depending upon
their specific concerns.
II. INDUSTRY OPTIMAL GOALS
A. Flight Vehicles
Light weight is the most important consideration, therefore, the stress is
pushed as high as possible. It would appear that %t~, ay~ would be
the most important consideration. However, the thin wall cross sections
will often buckle below the compression yield of the material and
can fail by fatigue even when the material is in compression. The loads
causing stress when properly defined are always varying. Variation in
the tension stresses causes fatigue and development of cracks in the thin
walls. As if this is not enough, thermal stresses will cause creep above
certain temperatures. In turn the performance created by the engines
must be prescribed to develop proper design parameters. The optimization entails
Chapter 3
their
Functional constraints are factors which engineers have studied in
undergraduate years and dealt with during career.
The last of the constraints is the regional constraint.
C. Regional Constraints
These are the physical limitations
1. Number of men in a shop
2. Gross weight of an aircraft not to exceed the design weight of the
runway
3. Truck widths less than one lane of a highway
These generally state that a parameter must be less or greater than a
stated number. The design criterion most engineers use are the equations
taught in undergraduate course work which are called functional constraints. Then to fabricate the design, vendors are selected and the lowest
cost or criterion function to fabricate is selected. The maximum sizes or
limitations on the design are regional constraints which for the most part
are common sense. However, when optimizing with a computer or
employing an analyst all of the above criterion function, functional constraints, and regional constraints must be stated as clearly as possible.
The first solution will show if the equations are not constrained by giving
answers like infinity, zero, or a negative dimension (all real values greater
than zero positive). Various industries optimize differently depending upon
their specific concerns.
II. INDUSTRY OPTIMAL GOALS
A. Flight Vehicles
Light weight is the most important consideration, therefore, the stress is
pushed as high as possible. It would appear that %t~, ay~ would be
the most important consideration. However, the thin wall cross sections
will often buckle below the compression yield of the material and
can fail by fatigue even when the material is in compression. The loads
causing stress when properly defined are always varying. Variation in
the tension stresses causes fatigue and development of cracks in the thin
walls. As if this is not enough, thermal stresses will cause creep above
certain temperatures. In turn the performance created by the engines
must be prescribed to develop proper design parameters. The optimization entails