ON THE EFFECTS OF CIRCULAR BOLT PATTERNS ON THE ...

5.6.1 Basis Of Hysteresis Development
5.6 Development Of Hysteresis Model Equation
The scope of this section is to summarized the different classifications and methods developed and
defined in this research to assist the designer to use a proper set of equations and hysteresis models
while predicting the outer envelope hysteresis characteristic and consequently the energy dissipation of
the extended end-plate connections. The summery of this section is presented in flowchart format in
Figure 5.8 This flowchart also can be implemented in the design software for more sophisticated design
procedures in the future.
The “condition” presented in Row-1 of this flowchart, indicated if the hysteresis behavior of the
connection with circular or square bolt pattern is been simulated.
Nonlinear regression analyses were performed to develop the dependent parameters required to
simulate the hysteresis behavior of the connection. These results are elaborated in detail in Section 5-6-3.
To increase the accuracy of the regression analysis and reduce the error in predicting the dependent
parameters, the numeric models are divided into two sub-categories based on the relation between the
end-plate thickness, and bolt diameter. The definitions of these two categories are also provided in
Section 5-6-3. The conditions presented in the Row-2 of the flowchart assist the engineer to use a proper
category, Category-1 or Category-2, while simulating the hysteresis behavior of the connection.
Also, as it was presented in Section 5.4, the hysteresis behaviors of the models were divided into two
sub-categories; “End-Plate Behavior”, and “Bolt Behavior”. The threshold between these two hysteresis
behavior was defined by the bolt diameter. This condition is implemented in the Row-3 of the flowchart.
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