Double-Layer Concentric Loading Frame for True Triaxial Testing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional true triaxial testing machines face challenges with stiffness insufficiency, leading to elastic shock waves and accelerated rock fracture during compression testing of hard rocks, and have design issues such as space wastage, non-compact structure, high frame span, and limited lifting capacity.
Innovation Solution
A double-layer concentric loading frame structure comprising an inner-layer cylindrical frame and an outer-layer circular ring structure with actuators and lifting driving cylinders, providing improved stiffness and a compact design, allowing for enhanced servo feedback control and efficient rock specimen mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional single-layer loading frame structure is used, then the structure is simple, but the stiffness is insufficient leading to elastic shock waves and accelerated rock fracture
Solution Approach 1:
The patent employs a double-layer concentric loading frame structure where an inner cylindrical frame is nested within an outer circular ring frame. Both frames share a common central axis and are vertically mounted on a base, creating a nested configuration that significantly increases the moment of inertia and structural stiffness without excessive complexity increase
Solution Approach 2:
The loading frame utilizes a composite structural design combining two different geometric configurations (cylindrical and circular ring) made from carbon steel material. This composite approach allows optimization of stiffness characteristics while maintaining structural integrity and controlling overall complexity
2Reliability
If the loading frame stiffness is increased to prevent elastic shock waves, then rock fracture safety improves, but the frame span increases and lifting capacity is limited
Solution Approach 1:
The nested double-layer frame structure increases structural stiffness without proportionally increasing the outer dimensions. The inner cylindrical frame and outer circular ring frame work together to provide enhanced stiffness while maintaining a compact overall footprint, thus improving safety without significantly increasing frame span
Solution Approach 2:
The patent transitions from a conventional single-layer planar structure to a three-dimensional nested configuration. The vertical mounting of both frames on the base with the inner frame nested within the outer frame creates a spatial structure that achieves higher stiffness-to-span ratio, improving safety while controlling frame span
3Volume of moving object
If a conventional loading frame structure is used, then the design is straightforward, but space is wasted and the structure is non-compact
Solution Approach 1:
The nested configuration of the inner cylindrical frame within the outer circular ring frame maximizes space utilization. The concentric arrangement allows the structure to occupy minimal footprint while providing the required structural functionality, achieving a compact design that does not sacrifice manufacturing feasibility
Solution Approach 2:
The patent employs curved geometric forms including a cylindrical inner frame and a circular ring outer frame. These curved configurations are inherently more space-efficient than angular structures, allowing the loading frame to achieve a compact footprint while maintaining structural strength and ease of manufacture
Data Source
AI summary
A double-layer concentric loading frame structure suitable for a true triaxial testing machine includes an inner-layer frame, an outer-layer frame and a base. A square slot hole is formed in a middle part of the inner-layer frame. The inner-layer frame is mounted on the base through a support platform. Actuators are mounted at a top end and a bottom end of the inner-layer frame. The outer-layer frame sleeves the inner-layer frame concentrically. Four actuators are distributed on an outer periphery of the outer-layer frame. A support plate is mounted at the top end of the inner-layer frame, and two lifting driving cylinders are mounted on the support plate. Piston rods of the lifting driving cylinders extend below the support plate and are connected to an upper surface of the outer-layer frame. A guide post is mounted on the upper surface of the outer-layer frame and extends above the support plate.