Silicon Carbide Honeycomb Structure Segmentation

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Solution Overview

Problem

Honeycomb structures made from silicon carbide, used in high-temperature corrosive environments, face issues with thermal shock resistance and material yield due to large thermal expansion coefficients, leading to defects and increased pressure loss when scaled up, and require additional machining steps for circular cylindrical shapes.

Innovation Solution

A honeycomb structure with partial segments separated by slits and a buffer portion filled in these slits, featuring an arc-shaped boundary wall with a specific radius and thickness ratio, which reduces thermal shock vulnerability and minimizes pressure loss, and eliminates the need for outer periphery machining.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a large-sized honeycomb structure is manufactured using silicon carbide, then the thermal resistance and chemical stability are improved, but thermal shock resistance deteriorates due to large thermal expansion coefficient

Engineering Contradiction:
Improvethermal resistanceVSAvoidthermal shock resistance
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The honeycomb structure is divided into multiple small plugged honeycomb structured segments that are bonded together to form a large-sized structure. This segmentation reduces thermal shock vulnerability by creating smaller units with lower thermal mass, preventing catastrophic failure across the entire structure when thermal shock occurs.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses silicon carbide as the framework material which provides excellent thermal resistance and chemical stability. The composite structure combines silicon carbide segments with bonding material to create a large-sized honeycomb structure that maintains the thermal resistance properties while mitigating thermal shock through the segmented architecture.

Inventive Principle:
Principle #40Composite materials

2Reliability

If rectangular parallelepiped segments are bonded to form a large honeycomb structure, then the thermal shock resistance is improved, but manufacturing complexity increases due to bonding process

Engineering Contradiction:
Improvethermal shock resistanceVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The structure is divided into multiple small plugged honeycomb structured segments that can be manufactured independently using standard extrusion processes, then bonded together. This segmentation allows for simplified manufacturing of individual units while achieving the thermal shock resistance of a large structure through assembly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A bonding material is used as an intermediary to join the silicon carbide segments together. This bonding material facilitates the assembly process, creating a large-sized honeycomb structure from smaller segments while managing the complexity of the manufacturing process through a standardized joining method.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If outer periphery machining is performed on bonded segments to obtain circular cylindrical shape, then the dimensional accuracy is improved, but material yield deteriorates due to coarse machining removal

Engineering Contradiction:
Improvedimensional accuracyVSAvoidmaterial yield
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

The honeycomb structure is designed with a circular cylindrical or oval outer periphery from the initial extrusion forming stage, before bonding the segments together. This preliminary shaping eliminates the need for subsequent coarse machining operations, preserving material and simplifying the manufacturing process while maintaining dimensional accuracy.

Inventive Principle:
Principle #10Preliminary action

4Reliability

If segments are bonded together to form a large honeycomb structure, then the thermal shock resistance is improved, but pressure loss increases due to thick bonding portions

Engineering Contradiction:
Improvethermal shock resistanceVSAvoidpressure loss
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The bonding material is applied only on specific side faces of the segments rather than uniformly across all surfaces. This localized bonding approach creates thick bonding portions only where structural integrity is needed, while maintaining thin partition walls in the flow paths to minimize pressure loss. The bonding is concentrated at the segment interfaces rather than throughout the entire structure.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2233194B1Honeycomb structure
Publication Date: 2011.06.08 NGK INSULATORS LTD
  • EP2233194B1 patent drawingFigure 1A
  • EP2233194B1 patent drawingFigure 1B
  • EP2233194B1 patent drawingFigure 2

AI summary

There is provided a honeycomb structure 100 provided with: a honeycomb structured portion 4 having partition walls 8 separating and forming a plurality of cells 1 and having a plurality of partial segments 3 separated and formed by a plurality of slits 2 extending along a cell 1 extension direction and being open on an end face on one side, and a buffer portion 5 disposed in the slits 2. In a cross section perpendicular to the cell 1 extension direction, each of the partial segments 3 is formed by a first region 11 having an outer periphery surrounded by a boundary wall formed by smoothly connecting a straight line and a curving line and a second region 12 being located to be adjacent to the first region 11 on the outside thereof and having a corner portion 13, and an R portion 15 as an arc-shaped portion of the boundary wall 14 is disposed inside the position having the corner portion 13 of the second region 12 of each of the partial segments 3, and the R portion of the boundary wall 14 has an arc shape having a radius of 1.5 to 10 mm, and the thickness of the boundary wall is 1.1 to 2.0 times the thickness of the partition wall.