CFRP Assembly Jig Thermal Expansion Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The assembly of large CFRP-panels in aircraft construction faces challenges due to positioning tolerance deviations between the panels and the jig construction, primarily caused by differing thermal expansion coefficients between CFRP-material and steel-based jig materials.
Innovation Solution
Incorporating metal bars with a thermal expansion coefficient matching that of CFRP-material, such as Invar steel, into the base frame of the assembling jig to compensate for thermal expansion and maintain precise positioning, along with curved positioning boards and clip elements for secure mounting of panel structure elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If steel-based materials are used for the assembling jig base frame, then the jig provides sufficient structural strength and rigidity, but the positioning tolerance deviates due to different thermal expansion coefficients between steel and CFRP-material
Solution Approach 1:
The patent changes the material parameter (thermal expansion coefficient) of the base frame from conventional steel to a material with thermal expansion coefficient matching CFRP (such as aluminum alloy or composite materials). This parameter adjustment ensures that both the jig and the panel expand or contract at the same rate during thermal cycles, maintaining positioning tolerance while preserving structural strength
Solution Approach 2:
The patent employs composite materials or specially selected alloys for the base frame that combine the necessary mechanical strength with a thermal expansion coefficient matched to CFRP. This may involve using aluminum alloys, titanium alloys, or composite structures that achieve both strength requirements and thermal expansion compatibility
2Ease of manufacture
If the assembling jig is made entirely of one material, then the manufacturing process is simple, but it cannot compensate for thermal expansion differences between the jig and the CFRP-panel
Solution Approach 1:
The patent applies different materials to different parts of the assembling jig based on their specific functional requirements. The base frame uses materials with thermal expansion matched to CFRP for dimensional stability, while other components may use conventional materials. This localized material selection optimizes both manufacturing complexity and positioning precision
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 effectively minimizes positioning tolerance deviations, ensuring accurate assembly and tight design integration by aligning the thermal expansion of the jig with the CFRP-panel, enhancing assembly capabilities and design precision.
Implementation Method 1
the metal bar consists of a material having a thermal expansion coefficient which corresponds to the thermal expansion coefficient of the CFRP-material of the panel in order to provide a tolerance compensation system
Data Source
Figure 1~2
AI summary
Assembling jig for mounting panel structure elements onto a surface of a CFRP-panel (1), comprising a base frame (6; 6a, 6b) on which several positioning boards (5) are transversely attached, which are parallel arranged one to another for supporting the CFRP- panel (1) on an upper mounting surface (3), wherein the base frame (6; 6a, 6b) comprises at least one metal bar (10a-10c) for coupling the positioning boards (5) consisting of a material having a thermal expansion coefficient which corresponds to the thermal expansion coefficient of the CFRP-material of the panel (1) in order to provide a tolerance compensation system in at least longitudinal direction (x) of the base frame (6).