Double-cross composite fabric membrane biaxial tensile test piece
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Solution Overview
Problem
Current methods fail to accurately test the biaxial tensile strength of flexible fabric membranes due to stress concentration effects at slits and edge chamfers, leading to damage and inability to characterize biaxial tensile stress effectively.
Innovation Solution
A double-cross composite fabric membrane biaxial tensile strength test piece is designed with a core region and four cantilevers forming a cross shape, where the cantilevers are connected to the core via an edge transition region and feature a clamping section with a rubber rod for biaxial tensile testing machines, ensuring tensile damage occurs in the core region, allowing for accurate biaxial tensile strength measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional uniaxial tensile test methods are used, then the test methodology is simple, but the biaxial tensile strength cannot be accurately characterized
Solution Approach 1:
The test piece is divided into distinct functional regions: a core test region for biaxial stress application, four cantilever arms for force transmission, and clamping sections for machine connection. This segmentation allows each region to be optimized for its specific function, enabling accurate biaxial tensile strength measurement while maintaining manageable structural complexity.
Solution Approach 2:
Different regions of the test piece have different structural characteristics: the core region has a specific geometry for biaxial stress concentration, the cantilevers have varying thicknesses (double-layered in some sections, single-layered in others) for optimized force distribution, and the clamping sections have rubber rods for secure attachment. This local differentiation ensures accurate stress application and measurement.
2Measurement precision
If slits and edge chamfers are introduced in the test piece, then the biaxial stress distribution is improved, but stress concentration effects cause damage and reduce measurement reliability
Solution Approach 1:
The core test region and cantilever connections feature curved transitions instead of sharp corners or slits. The rounded geometry eliminates stress concentration points that would cause premature damage, while still enabling accurate biaxial stress distribution across the test region.
Solution Approach 2:
The test piece geometry is carefully designed with specific dimensional parameters: the core region has optimized width and length ratios, the cantilevers have controlled thickness variations (single-layered vs. double-layered sections), and the clamping sections have standardized dimensions. These parameter optimizations ensure both accurate stress distribution and adequate damage resistance.
3Strength
If the cantilever and edge transition region are made double-layered, then the structural strength is improved, but the manufacturing complexity increases
Solution Approach 1:
The test piece is constructed by bonding multiple fabric layers together: single-layered regions are bonded to double-layered regions, and the clamping sections combine three layers with rubber rods. This merging of layers creates the necessary strength variations throughout the structure while using standard fabric bonding processes.
Solution Approach 2:
The test piece uses composite construction with fabric layers bonded together in different configurations (single-layered core, double-layered cantilevers and transition regions, three-layered clamping sections). This composite approach provides the required strength distribution while maintaining manufacturability through conventional multi-layer bonding techniques.
Data Source
AI summary
A double-cross composite fabric membrane biaxial tensile strength test piece is provided, including a core region and four cantilevers. The four cantilevers extend outwards around the core region and form a cross shape. Each cantilever is connected to the core region via an edge transition region. An end portion of the cantilever is a clamping section. The clamping section is provided with a clamping end rubber rod. The clamping end rubber rod is used for connecting to a clamp of a biaxial tensile testing machine. The clamping section is three-layered. The cantilever and the edge transition region are double-layered. The core region is single-layered. The edge transition region is in the shape of a quadrangle rounded at four corners. A manufacturing method of the test piece is also provided.