Tension Testing Apparatus Using Rod Inversion for Concrete
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Solution Overview
Problem
Current methods for testing the tension strength of concrete, such as ASTM C496 and C78, rely on theoretical equations with significant assumptions, leading to overestimated values, and direct tension testing machines are costly and inaccessible to many laboratories.
Innovation Solution
A tension testing apparatus comprising two boxes with interconnected plates and rods, allowing for the application of both compressive and tensile forces to a test sample, enabling direct tension testing without the need for expensive machinery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional compression testing (ASTM-C39) is used, then the testing method is simple and widely available, but the tension strength cannot be directly measured and must be calculated using theoretical equations with significant assumptions leading to overestimated values
Solution Approach 1:
The patent applies compression force to the outer plates, which through the rod mechanism is inverted into tensile force on the inner plates and test sample. This allows using a conventional compression testing machine to achieve direct tension testing, resolving the contradiction by measuring tension strength accurately without requiring a specialized expensive tension testing machine.
Solution Approach 2:
The rod system acts as an intermediary mechanism that transfers and transforms the compression force applied to outer plates into tensile force on the inner plates and test sample. This mediator enables the conversion of compression to tension, allowing accurate tension strength measurement using compression testing equipment.
2Measurement precision
If direct tension testing machines are purchased, then accurate tension strength measurement is achieved, but the capital investment cost exceeds $500,000 making it prohibitive for many laboratories
Solution Approach 1:
The patent creates a functional copy of direct tension testing capability using a different mechanism - applying compression to outer plates that translates to tension on inner plates through rods. This copy achieves the same measurement accuracy as expensive direct tension machines but costs a fraction of the price, making it accessible to limited access laboratories.
Solution Approach 2:
The apparatus can be used with conventional compression testing machines, making the existing compression testing infrastructure multi-functional. The same compression machine can now perform both compression testing and tension testing by simply changing the sample configuration to this apparatus, eliminating the need for separate expensive tension testing equipment.
3Ease of operation
If splitting tensile strength test (ASTM C496) is used, then the test configuration is simpler, but the calculated values are significantly greater than direct tension values due to theoretical equation assumptions
Solution Approach 1:
The apparatus directly measures tension strength through the mechanical configuration of rods and plates without requiring theoretical equations or calculations. The test sample itself serves to directly indicate its tensile strength through failure under the induced tension, eliminating the need for assumption-based calculations while maintaining operational simplicity.
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
Provides accurate and cost-effective direct tension testing of concrete samples, overcoming the limitations of existing methods by allowing for precise measurement of tension strength without the high capital investment required for specialized machines.
Implementation Method 1
The two boxes provide tension in the test sample while applying a compressive load
Data Source
AI summary
A tension testing apparatus and system is disclosed in which the tension testing apparatus includes a first box including a first outer plate and a first inner plate, a second box including a second outer plate and a second inner plate, and a test sample holding system coupled to the first inner plate and the second inner plate. The first outer plate and the first inner plate may be coupled together by at least two rods. The second outer plate and the second inner plate may be coupled together by at least two other rods. The test sample holding system may be configured to hold a test sample. The at least two rods of the first box may be configured to pass through the second inner plate. The at least two rods of the second box may be configured to pass through the first inner plate.