Heat Exchanger Seismic Analysis with Non-Linear Spring Elements
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Solution Overview
Problem
The existing methods for analyzing heat exchangers, particularly in seismic evaluations, face challenges in accurately predicting the load distribution and gap distribution between heat transfer tubes and anti-vibration members, leading to inaccuracies in seismic evaluations due to deformation during earthquakes.
Innovation Solution
A method involving the creation of structural models with non-linear and linear spring elements to simulate the behavior of heat transfer tubes and anti-vibration members, allowing for the analysis of load and gap distributions, and applying these models to perform response analysis considering seismic waves, thereby improving the accuracy of seismic evaluations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a linear spring element is applied to all opposing portions between heat transfer tubes and anti-vibration members, then the analysis model is simple, but tension load is generated even when gaps exist, leading to inaccurate seismic evaluation
Solution Approach 1:
The patent applies different spring element types to different locations based on local conditions. Non-linear spring elements are applied to opposing portions where gaps may occur (allowing separation without tension), while linear spring elements are applied where continuous contact is expected. This local differentiation resolves the contradiction by maintaining model simplicity where appropriate while ensuring accuracy where gaps occur.
2Measurement precision
If a non-linear spring element is applied to simulate contact behavior between heat transfer tubes and anti-vibration members, then the accuracy of load distribution and gap distribution is improved, but the analysis complexity and time increase
Solution Approach 1:
The patent segments the opposing portions between heat transfer tubes and anti-vibration members into different categories: portions where gaps may occur (using non-linear spring elements) and portions where continuous contact is maintained (using linear spring elements). This segmentation reduces the overall number of non-linear elements required, thereby decreasing analysis time while maintaining accuracy in critical gap regions.
3Device complexity
If the entire heat exchanger is analyzed as a continuous structure, then the structural model is simple, but the load distribution and gap distribution between heat transfer tubes and anti-vibration members cannot be accurately determined
Solution Approach 1:
The patent introduces spring elements as intermediary components between heat transfer tubes and anti-vibration members. These spring elements (both linear and non-linear types) act as mediators that simulate the contact and separation behavior, enabling the structural model to capture load distribution and gap distribution accurately while maintaining overall model simplicity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enhances the accuracy of seismic evaluations by simulating the actual behavior of heat transfer tubes and anti-vibration members, reducing analysis time by using linear models for dynamic analysis and non-linear models for static analysis.
Implementation Method 1
a non-linear spring element in the out-of-plane direction, in which a load is not generated at the time of non-contact between the heat transfer tube and the anti-vibration member and a load is generated at the time of contact
Implementation Method 2
a linear spring element in the in-plane direction is applied to each of the opposing portions in the structural model using a value according to the load of each of the opposing portions as elastic stiffness
Data Source
AI summary
A method for analyzing a heat exchanger includes a structural model creation step (S1) of creating a structural model of a heat exchanger; a iron-linear model creation step (S4) of creating a iron-linear model in which a non-linear spring element in an out-of-plane direction, in which a load is generated only at me time of contact between a heat transfer tube and an anti-vibration member, is applied to an opposing portion between the heat transfer tube and the anti-vibration member in a structural model, and a load distribution acquisition step (S5) of performing analysis in which a load in the out-of-plane direction is applied to the non-linear model to acquire load distribution of the heat exchanger from a value of the load in each opposing portion.