Stochastic Isogeometric Blade Design for Marine Current Turbines

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Solution Overview

Problem

The design of high-rigidity blades for marine current power generators faces challenges in accurately representing the randomness of material properties and external loads, leading to inefficiencies in stochastic response analysis and increased costs with experimental methods, while simulation methods struggle with discretizing stochastic displacement effectively.

Innovation Solution

A method using stochastic isogeometric analysis to parameterize blade airfoils, determine design parameters, and establish random field models for material and load properties, combined with a genetic algorithm to optimize blade design for high-rigidity requirements, ensuring accurate representation of stochastic uncertainties and hydrodynamic performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If experimental methods are used for stochastic response analysis, then accuracy of response information can be obtained, but cost and time consumption increase significantly due to manufacturing numerous blades

Engineering Contradiction:
Improveaccuracy of response informationVSAvoidcost and time consumption
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent creates virtual copies of the blade through numerical simulation models that replicate the physical blade's stochastic response characteristics. These digital twins allow researchers to obtain response information (displacement, stress, etc.) under various loading conditions without manufacturing actual physical prototypes, thereby achieving measurement accuracy while eliminating the high costs and time consumption of experimental methods.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces the physical mechanical testing system with a numerical simulation system. By using finite element analysis and stochastic modeling, the mechanical response of the blade is computed virtually rather than measured physically, substituting computational mechanics for experimental mechanics and resolving the contradiction between accuracy and productivity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If simulation methods are used to modify blade size, then efficiency and cost are improved, but difficulty in discretizing stochastic displacement arises

Engineering Contradiction:
Improveefficiency and costVSAvoiddifficulty in discretizing stochastic displacement
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent transforms the stochastic displacement field from a continuous random process into a discrete representation by identifying and analyzing its statistical parameters (mean, variance, covariance functions). This parameter transformation allows the complex stochastic displacement to be handled through systematic discretization methods, converting an intractable problem into one that can be efficiently solved numerically while maintaining productivity gains.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If blade rigidity is increased to withstand severe weather, then reliability improves, but weight and manufacturing cost increase

Engineering Contradiction:
Improveblade resistance to severe weatherVSAvoidblade weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent applies local quality optimization by identifying specific regions of the blade that require enhanced rigidity to withstand severe weather conditions, rather than uniformly increasing the entire blade's weight. Through stochastic response analysis, the patent determines critical areas where material reinforcement is necessary and applies localized structural modifications, achieving improved reliability while minimizing overall weight increase.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs dynamic optimization by considering the stochastic nature of loading conditions and material properties. Rather than designing for worst-case static loads, the patent models the dynamic interaction between random waves, currents, and blade response, allowing for more efficient structural designs that maintain reliability under varying environmental conditions without excessive weight penalties.

Inventive Principle:
Principle #15Dynamics

4Measurement precision

If stochastic field models are established for material and load properties, then accuracy of randomness representation is improved, but computational complexity increases

Engineering Contradiction:
Improveaccuracy of randomness representationVSAvoidcomputational complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the stochastic field models into manageable components by separating material property randomness from load randomness, and further dividing each into discrete random variables through discretization. This segmentation allows the complex stochastic analysis to be broken down into sequential computational steps, maintaining accurate randomness representation while reducing overall computational complexity through systematic decomposition.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS11977823B2Method for designing high-rigidity blade based on stochastic isogeometric analysis
Publication Date: 2024.05.07 ZHEJIANG UNIV
  • US11977823B2 patent drawing
  • US11977823B2 patent drawing
  • US11977823B2 patent drawing

AI summary

In a method for designing a high-rigidity blade based on stochastic isogeometric analysis, the models of stochastic fields of the material property and the external load of the blade are established based on manufacturing conditions and service environment of the blade; an optimization model of the blade is established according to high-rigidity design requirements of the blade and a constraint condition of lift-drag ratio, which is then solved. In the solution procedure, a stochastic isogeometric analysis method is used to calculate the stochastic displacement of the blade under the influence of the randomness of the material property and the external load, and the maximum lift-drag ratio of the blade airfoil is also calculated, based on which the fitness values of individuals in the current population are calculated, so that the high-rigidity design of the blade is realized in the premise of ensuring the lift-drag ratio.