Spherical Support Mechanism for CFRP Three-Point Bending

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Solution Overview

Problem

Material testing machines face challenges in applying a uniform testing force during three-point bending tests on carbon fiber reinforced plastic (CFRP) due to precision issues with indenters and support structures, leading to non-uniform loading and local breakage.

Innovation Solution

A material testing machine with a support mechanism featuring a spherical seat and holding portion that allows for adjustable alignment of the testing piece and indenter, enabling precise application of ultrasonic vibrations and pressing forces through a sliding mechanism with spherical surfaces, ensuring a uniform testing force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a fixed support mechanism is used for the testing piece, then the structure is simple, but the alignment between the indenter and testing piece cannot be adjusted, leading to non-uniform testing force

Engineering Contradiction:
Improvealignment precisionVSAvoidsupport mechanism complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The support mechanism employs a spherical seat with a spherical surface that allows the upper member to rotate and slide relative to the lower member. This spherical geometry enables multi-directional adjustment of the testing piece alignment without requiring complex mechanical linkages, achieving precise alignment through curved surface interaction.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The support mechanism transitions from a fixed rigid structure to a dynamic adjustable system. The upper member can slide along the spherical surface and rotate, allowing real-time adjustment of the testing piece position and angle to achieve proper alignment with the indenter, thereby converting a static structure into an adaptable dynamic system.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the testing piece and indenter are not properly aligned, then the setup is simple, but non-uniform testing force is applied causing local breakage

Engineering Contradiction:
Improvetesting reliabilityVSAvoidalignment adjustment
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The spherical seat provides a natural rotation axis that simplifies the alignment process. By allowing rotation around the spherical center, the system enables easy angular adjustment of the testing piece to match the indenter angle, making the alignment operation straightforward while ensuring reliable uniform force application.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The support mechanism adds rotational and sliding degrees of freedom to the alignment process. Instead of requiring precise initial positioning in a fixed structure, the system allows adjustment in multiple dimensions (rotation around spherical axis and sliding along the surface), making alignment easier to achieve and verify.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 configuration allows for accurate and uniform application of testing forces, preventing local breakage and ensuring reliable material testing by adjusting the position and angle of the testing piece and indenter, thereby ensuring consistent material testing results.

Implementation Method 1

a spherical seat that has a lower member equipped with a spherical-surface-shaped concave portion or convex portion, and an upper member equipped with a spherical-surface-shaped concave portion or convex portion having a shape corresponding to the concave portion or convex portion in the lower member

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

an indenter that is connected to an ultrasonic oscillator and gives ultrasonic vibration to the testing piece by abutting against the testing piece

Methodology Applied
Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Data Source

PatentEP3795978B1Material testing machine
Publication Date: 2023.06.14 SHIMADZU CORP
  • EP3795978B1 patent drawingFigure 1
  • EP3795978B1 patent drawingFigure 2
  • EP3795978B1 patent drawingFigure 3

AI summary

Provided is a material testing machine capable of giving an appropriate testing force to a testing piece. The material testing machine performs a three-point bending test on a testing piece and includes a support mechanism that supports the testing piece, an indenter 22 that is connected to an ultrasonic oscillator 23 and gives ultrasonic vibration to the testing piece by abutting against the testing piece, and a load mechanism that presses the indenter 22 to the testing piece supported by the support mechanism. The support mechanism includes: a spherical seat 50 that has a lower member 51 equipped with a spherical-surface-shaped concave portion or convex portion, and an upper member 52 equipped with a spherical-surface-shaped concave portion or convex portion having a shape corresponding to the concave portion or convex portion in the lower member 51; a holding portion 30 that supports the testing piece on the upper member 52; and a first movable member that causes the upper member 52 to slide along the spherical surface with respect to the lower member 51.