Honeycomb Structure Strength Measurement Using Rubber Plug
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Measuring the strength of a honeycomb structure with inserted sensors is challenging due to the difficulty in avoiding crack formation at the hole edge portions during isostatic breakdown strength tests, which affects the accuracy and longevity of sensor function.
Innovation Solution
A method involving a rubber plug with specific hardness and shape, including a recessed portion, is used to measure the strength of honeycomb structures with inserted sensors, ensuring the plug's protruding height and clearance prevent urethane from biting into the hole and absorb external forces, thereby avoiding crack formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If isostatic breakdown strength test is performed on honeycomb structure with insertion hole, then strength measurement is attempted, but hole edge portions are cracked by urethane wrapping or urethane is broken
Solution Approach 1:
A rubber plug is inserted into the insertion hole to serve as an intermediary element between the honeycomb structure and the urethane wrapping material. The rubber plug absorbs the stress concentration that would otherwise occur at the hole edge, preventing crack formation in the honeycomb structure and preventing urethane breakage, thereby enabling valid strength measurements.
Solution Approach 2:
The rubber plug is installed in advance into the insertion hole before the urethane wrapping process. This pre-installation cushions the hole edge against stress concentration during the subsequent isostatic breakdown strength test, preventing crack formation and ensuring the structural integrity needed for accurate strength measurement.
2Reliability
If sensors are inserted into holes in honeycomb structure, then sensor protection and stability are improved, but strength measurement becomes difficult due to crack formation at hole edges
Solution Approach 1:
The rubber plug acts as an intermediary element that allows both sensor installation and strength measurement to coexist. It protects the sensor insertion hole from stress concentration during strength testing, maintaining sensor stability while enabling accurate strength measurement of the honeycomb structure.
Solution Approach 2:
The rubber plug is installed beforehand to cushion the hole edge, ensuring that subsequent strength measurements do not cause crack formation that would compromise either the sensor function or the measurement validity.
3Measurement precision
If rubber plug with small clearance is used, then measurement precision is improved, but hole edge portions are more susceptible to cracking
Solution Approach 1:
The hardness of the rubber plug is optimized to balance measurement precision and crack resistance. A rubber plug with hardness of 40-90 durometer is selected, which provides sufficient rigidity for accurate strength measurement while maintaining enough elasticity to absorb stress concentration and prevent crack formation at the hole edge.
Solution Approach 2:
The rubber plug provides localized protection at the hole edge while maintaining the overall structural integrity needed for measurement. The local cushioning effect at the insertion hole does not compromise the global strength measurement capability of the honeycomb structure.
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 allows for accurate measurement of the honeycomb structure's strength while simulating actual use conditions, ensuring the structure can withstand long-term loads and pressures, thus determining its suitability for sensor installation.
Implementation Method 1
a rubber plug with a hardness of 45 or more and 90 or less is inserted into the insertion hole
Implementation Method 2
the rubber plug has a recessed portion in the face thereof facing the inner surface of the insertion hole
Data Source
Figure 1A~1B
Figure 2A~3B
Figure 4~7
AI summary
There is disclosed a method for measuring the strength of a honeycomb structure provided with an insertion hole preferably without generating any chipping. In the strength measuring method of the honeycomb structure, the strength is measured while a rubber plug is inserted into the insertion hole. The rubber plug has a hardness of 45 or more and 90 or less, a clearance between the inserted rubber plug and the inner surface of the insertion hole parallel to the depth direction of the insertion hole is 0.2 mm or more and 2.6 mm or less, and the protruding height of the inserted rubber plug from the peripheral surface of the honeycomb structure is 0.5 mm or more and 5 mm or less.