Rheometer Segmentation for Granular Flow Measurement
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Solution Overview
Problem
Existing apparatus for measuring flow properties of granular materials and powders fail to accurately control and measure consolidating stress and strain, particularly at varying stress levels and strain rates, and cannot assess volumetric stress or strain, nor the memory effect of consolidating stress, due to limitations in design that either integrate stress and strain delivery or lack mechanisms for precise measurement.
Innovation Solution
A rheometer design featuring a rotating body and an independently movable sample container lid that allows for separate application and measurement of consolidating stress and rotational strain, enabling the assessment of flow properties across a wide range of conditions, including zero to high consolidating pressures and strain rates, with the ability to measure volumetric strain and stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the consolidating stress and rotational strain are delivered through the same component (lid or plate), then the device structure is simple, but it is not possible to test powder samples at high strain rates and measure volumetric strain accurately
Solution Approach 1:
The device segments the functions of stress application and strain measurement by separating the lid (for stress application) from the rotating body (for strain measurement). This allows independent control and measurement of consolidating stress and rotational strain, enabling accurate volumetric strain measurement even at high strain rates.
2Ease of operation
If the lid is used to deliver both consolidating stress and rotational strain, then the device is easier to operate, but the strain is delivered only to a thin layer of the sample and volumetric strain cannot be measured
Solution Approach 1:
The rotating body is introduced as a separate component that delivers rotational strain to the bulk of the powder sample, while the lid independently applies consolidating stress. This segmentation ensures that strain is delivered to the entire sample volume, not just a thin layer, enabling accurate measurement of volumetric strain.
3Ease of manufacture
If the same component delivers both stress and strain, then the device is simpler to manufacture, but the memory effect of consolidating stress cannot be measured
Solution Approach 1:
The independent rotating body allows the system to maintain consolidating stress through the lid while measuring rotational strain separately. This segmentation enables the detection of memory effects by measuring strain response after stress removal, as the rotating body continues to interact with the sample independently of the lid's stress application.
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
Enables comprehensive measurement of flow properties of granular materials and powders under controlled stress and strain conditions, simulating industrial scenarios and providing detailed insights into material behavior, including volumetric changes and stress memory effects.
Implementation Method 1
applying rotational strain to sample materials and measuring various stresses
Implementation Method 2
provision for applying consolidating stress to the sample
Implementation Method 3
measuring the forces required to rotate the body and move the lid
Data Source
AI summary
The invention relates to a rheometer comprising of a container for receiving a material sample to be investigated, a shaft with a rotating body which is immersed into the material sample, and a container lid that moves in the axial direction of the shaft into the sample container to deliver consolidating stress to the material sample. The forces acting on the material sample due to the rotation of the rotating body and the motion of the container lid and the location of the sample lid are measured as consolidating stress and rotational strain are applied and removed from the material sample.