Wind Turbine Rotor Blade Joint Thermal Expansion Matching
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Solution Overview
Problem
Dissimilar materials in wind turbine rotor blade joints experience thermally-induced stresses due to differing coefficients of thermal expansion, compromising structural integrity and maintaining clearances during operational temperature changes.
Innovation Solution
The use of pin joints with pin joint slots made of a metal material and load bearing blocks made of a composite material, where the coefficients of thermal expansion are equal or within plus or minus 20% of each other, ensuring contact and structural integrity during temperature changes from -40°C to 60°C, with the composite material optionally reinforced with fibers to match the thermal expansion of the metal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If dissimilar materials are used in rotor blade joints to achieve lightweight and cost-effective construction, then weight and manufacturing cost are reduced, but thermally-induced stresses compromise structural integrity
Solution Approach 1:
The patent applies parameter changes by carefully selecting and matching the coefficients of thermal expansion of dissimilar materials (metal and composite) used in the joint. By ensuring the thermal expansion coefficients are within a specific range of each other, the patent enables the joint to withstand thermally-induced stresses while maintaining structural integrity across temperature variations from -40°C to 60°C.
2Adaptability or versatility
If dissimilar materials with different coefficients of thermal expansion are used in rotor blade joints, then material diversity and design flexibility are increased, but clearance maintenance between components deteriorates
Solution Approach 1:
The patent resolves the clearance stability issue by changing the thermal expansion parameter relationship between dissimilar materials. By specifying that the coefficients of thermal expansion must be within a certain range of each other, the patent ensures that thermal dimensional changes remain compatible, thereby maintaining required clearances between components during operational temperature variations.
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 solution maintains contact between pin joint slots and load bearing blocks across a wide temperature range, enhancing the structural integrity and durability of wind turbine rotor blade joints by aligning thermal expansion coefficients, thus preventing thermally-induced stresses.
Implementation Method 1
the different coefficients of thermal of expansion between the dissimilar materials may compromise the structural integrity of the joint
Data Source
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AI summary
A rotor blade for a wind turbine includes a first blade segment and a second blade segment extending in opposite directions from a chord-wise joint. Each of the first and second blade segments includes at least one shell member defining an airfoil surface. The rotor blade also includes one or more pin joints for connecting the first and second blade segments at the chord-wise joint. The pin joint(s) includes one or more pin joint tubes received within the pin joint slot(s). The pin joint slot(s) are secured within a load bearing block. Further, a gap is defined between the pin joint slot(s) and the load bearing block. Moreover, the rotor blade includes a shim within the gap between the pin joint slot(s) and the load bearing block so as to retain the pin joint slot(s) within the load bearing block. In addition, the shim is constructed of a liquid material that hardens after being poured into the gap.