“A torsion tester is a device that uses a torsion beam to apply a twist to a specimen and measure the torque required to induce failure.” Research, development, and production engineers use torsion testers to determine a material’s ultimate tensile strength (UTS).
In other words, it measures the amount of force required to deform an object. It applies tension and then measures the resulting torque. The exact model of the torsional testing machine depends on its purpose – for example, a typical industrial testing machine is usually good for heavier loads than a laboratory model. These are critical for testing material quality and are widely helpful to the industry.
Now let us know more about the torsion testing machine here, it consists of several torsion testing machine parts :
- Strain head
- Torque reaction and measurement system
- Drive gearbox
- Precision encoder
- Torsion shaft
- Lever arm
- Torque sensor
- Drive socket.
Let’s take a closer look at torsion testing machine components:
Most torsion testing machines have a strain head and a torque reaction system at one end. The torsion testing machine consists of a lever arm, a torque transducer to hold the sample, and a load cell to measure the torque. Typically, students turn a twist handle to apply force to drive a gear within the machine. It guides the shaft longitudinally from input to output, allowing for any change in sample length during testing and easy sample insertion.
The encoder measures any tilt or movement relative to continuous rotation. While this will not directly calculate the rotation angle, it will display the angular displacement on the simulated display. In addition, another gauge to measure torque is built into one or both sides of the driveline. For example, one gauge can monitor rotation and twist (torque), while another gauge can measure twist, but not front-to-back bending (torque).
Let’s take a look at some of the uses of torsion testing machines:
- Torsion testing machines are essential quality assurance instruments in the industrial sector, helping to ensure that your manufactured products can withstand the stress and pressure applied.
- Torsion testing machines facilitate physical experiments in the laboratory to determine how objects made of various materials respond to torsional stress (such as twisting) when loaded due to opposing forces and moments.
- Torsion testing typically has multiple values and units, including Young’s modulus, shear modulus, shear strength, fatigue life, torsional ductility, ultimate tensile strength and ductility, and coefficient of rupture in tension/compression testing. They are both important in the laboratory because they standardize mechanical engineering practices by ensuring quality control (QC) before large-scale production runs, thereby minimizing defects or other problems while eliminating wasted production costs or wasted materials/components (waste reduction).
Have you ever wondered how a torsion testing machine works? Torsion testing is a non-destructive practical examination in materials engineering and mechanical engineering to determine the stiffness of an object.
Here let us first understand the principle of the test machine:
- A typical test involves twisting one end of the material, which is turned to apply pressure to it, using an instrument called a twister. In this way, the device exhibited internal deformation after being twisted for a specific amount of time, indicating a reduction in the elasticity and force required to continue rotating the material.
- The torsion testing machine uses the torsion of a rotating ball to drive the load-bearing crosshead up and down. An electric motor controls a series of pulleys and gears that turn the screw and move the crosshead.
- A torsional force for a torsion test is applied to a test specimen by anchoring one end so that it cannot move or rotate, and applying a moment at the other end to cause the model to rotate about its axis.
If a material fails, it suffers from an ultimate failure mode, usually plastic flow or fracture. Torsion testing machines are helpful in evaluating such mechanical behavior. Depending on the requirements of the industry, there are different torsion testing machines. Let’s learn about some torsion testing machines:
1) Digital torsion testing machine
The digital torsion testing machine tests tensile strength or elasticity. It is a torsion testing machine that helps in evaluating the tensile strength of materials. The device will determine how many kilograms it takes for a sample of the material to break when it is stressed and stretched, giving you an idea of its elasticity.
It measures a material’s ability to resist torsion by measuring its torque-torsion properties. It helps in testing construction materials, cardboard, rubber, textiles, and other materials that are subjected to stress when twisted. The results provide information about the material’s stiffness and resistance to cracking or fracture.
In a digital torsion testing machine, the output of the test is displayed on a digital display, allowing us to take a direct reading.
2) Torsion spring testing machine
Torsion spring testing machines can be used to test the strength of torsion springs, which store mechanical energy in torsional stress rather than compressive or tensile stress. This machine can utilize different types of test samples to measure the maximum load capacity and elongation or contraction of the spring.
The torsion spring testing machine is a practical device to test the strength of a spring and ensure that it can withstand a given load. The platen and upper head are assembled with the base and lower head to form a complete model. The torsion testing machine is mainly used in the machinery industry such as the automobile industry, the aerospace industry, the mining machinery industry, and other industries that have a large demand for torsion springs.
3) Horizontal torsion testing machine
Horizontal torsion testing machines use special springs to apply force and then measure the torque required to twist an object by a given angle. In addition to providing conventional pulling or pushing forces, it also provides torsional moments. This additional capability helps the operator determine the shear and tensile strength of the material. It tests the tensile and flexural strength of automotive industry tools and materials.
4) Vertical torsion testing machine
The vertical testing machine is widely used in the single-column test and two-column test of engineering structures such as nuclear power plant equipment, boilers, pressure vessels, bridges, large crane chassis, and high-rise buildings. Vertical torsion testing machines help determine elastic properties such as stiffness, toughness, and Young’s modulus.
The unit features a linear slide design for maximum torsional stiffness and minimum axial friction. It is equipped with a reactive torque sensor mounted on a movable tailstock mounted on a linear slide that applies force at right angles to the axis of rotation.
5) Torsional stiffness testing machine
Torsional stiffness testing machines can be used to determine the torsional stiffness of a particular material. It can be a plate, beam, or rod. The machine applies a sinusoidal load to the sample and measures the rotation of the phantom using an LVDT attached to the sample. It helps to find the shear modulus of elasticity and to determine the failure pressure and strain.
It is used in the engineering and metallurgical industries to subject materials to torsion. Such machines can be classified as instrumented torsional testing systems or non-instrumented testing machines.
6) Old vertical torsion testing machine
A vintage vertical torsion tester is a device that measures the shear modulus and damping of materials. Using force along a material’s axis and torque measurement, it determines its modulus of elasticity and other mechanical properties. The sample is vibrated vertically with a specified angular acceleration. It is suitable for the detection and quality control of steel wire ropes.
It is an important machine for determining how quickly materials can be damaged by mechanical vibration, helping you design products with better durability.
7) Axial torsion testing machine
An axial torsion testing machine is a testing machine for the torsion performance of shafts and other circular parts. It is used to measure the torque required to cause torsional deformation (torsion) of a specific area of a material. It applies both torque and axial load (also known as axial force). The sample can be one of many different shapes, such as circles, squares, triangles, rectangles, etc.
It does this by applying a known force on the sample and measuring the maximum amount of deformation, if any, that occurs before failure.
8) Optical fiber torsion testing machine
An optical fiber torsion testing machine is a useful piece of equipment for measuring the mechanical properties of optical fiber. It is an important tool for testing fiber performance during construction and after installation. It performs torsion tests on fiber optic cables under tension and temperature. The machine applies a specific amount of twist to a test sample and measures the change in attenuation of light propagating through the sample.
It allows you to test the mechanical properties of the fiber, which can help you determine the best components to use when assembling or designing cables. This instrument is of extensive assistance in the production, maintenance, and quality control of optical fibers to ensure that the optical fibers meet their transmission requirements.
9) Wire torsion testing machine
The wire torsion tester helps determine the strength and elasticity of the wire. This device measures the torque required to twist an object under controlled conditions as a function of angular displacement. It measures the amount of twist applied to a sample under controlled conditions as a function of applied torque.
It also helps determine how much torsional strain the wire can withstand without breaking. It precisely measures the torque required to turn a nut or bolt without applying any additional stress to the material being tested. It is used in physical experiments to resist by twisting a wire and measuring its breaking force, and in industrial R&D for material characterization and product testing.
10) Simulation torsion testing machine
The simulated torsion testing machine tests the material stress-strain response of manufactured products. The product under test is subjected to increasing loads until failure and the output is recorded as a function of applied force, displacement, or time. The simulated torsion testing machine is the most commonly used torsion testing machine.
It has the advantages of high accuracy, convenient use, and fast detection results. The analog torsion testing machine is equipped with a high-precision potentiometer system, which can be set at any angle to measure and control torsion. You can mainly produce torque wrenches and indicators with this machine.
11) Cement tensile torsion testing machine
The cement tensile torsion testing machine is a special equipment for torque testing of cement samples. It has high precision, strength, and flexibility. It can be used on the construction site to inspect the quality of the power of concrete mixers and building materials, such as concrete and mortar cement plant products.
It tests the breaking strength and material elongation of concrete. It measures high-performance concrete (HPC) physical properties such as compressive strength, flexural strength, modulus of elasticity, etc.
As we all know, there are many types of torsion testing machines. The price of a torsion testing machine varies depending on the type of machine, features, labels, and other factors. The average price range for a torsion testing machine is around INR 75,000 to INR 185,000, depending on the brand.
For a horizontal torsion testing machine for university use, the price range is around INR 35,000 to INR 200,000 depending on the brand and specification of the product.
Before we tackle the minimum number of torsion testing machines, let us understand. The minimum number of torsion testers is the minimum number of turns that will provide the sample with an elastic limit, depending on the material and applied stress. The minimum torque that can be tested by the testing machine is 0.006-0.06 Nm. Of course, it depends on the device, different models are different, so the minimum count may be different.
Torsion testing is a common method for evaluating the mechanical properties of materials, such as modulus of stiffness, shear stress, and shear strain. However, like any other testing technique, it has some challenges and limitations that you should be aware of before performing or interpreting the results. The objective of this article is to discuss some of the main factors that affect the accuracy and reliability of torsion testing, and how to overcome or minimize them.
1) Sample preparation
One of the first challenges in torsion testing is preparing samples of the proper shape and size for testing. For torsional testing, the sample must have a uniform cross-section, preferably round or square, and be free of defects, cracks, or surface irregularities. The sample must also be properly aligned with the axis of the twister and clamped securely to avoid slipping or bending during testing. Any deviation from these conditions may result in inaccurate or inconsistent measurements of torque, torsion angle, and shear stress.
2) Behavior of the material
Another challenge of torsion testing is to consider the complex and nonlinear behavior of some materials under torsional loading. For example, some materials may exhibit elastoplastic behavior, where the shear stress-strain curve is not linear beyond the elastic limit, or anisotropic behavior, where properties depend on the loading direction.
These factors affect the calculation of the modulus of stiffness, which is based on the assumption of a linear elastic relationship between shear stress and shear strain. Therefore, you need to choose an appropriate material model and test parameters to properly analyze the data.
3) Strain measurement
The third challenge of torsion testing is to measure strain accurately and accurately. Unlike tension or compression testing, where strain can be measured directly by using extensometers or strain gauges, torsion testing requires measuring the angle of torsion of a sample, which is then converted to shear strain by using the geometry and dimensions of the sample.
However, this method has some limitations, such as the difficulty of attaching a device to measure the twist angle, the sensitivity of the measurement to alignment and clamping errors, and the uncertainty of the measurement due to friction, backlash, or hysteresis in the twisting machine.
4) Test standard
A fourth challenge in torsion testing is following the proper testing standards and procedures for different materials and applications. Standards and specifications define sample preparation, test setup, test speed, data acquisition, and data analysis methods for torsion testing of metals, polymers, composites, and other materials. There are a number of ASTM standards, including E143, D1043, D5448, and ISO 6721. You need to review and adhere to these standards to ensure the validity and comparability of your test results.
5) Limitations of the test
A final challenge with torsion testing is recognizing its limitations and applicability. Torsion testing can be used to measure the modulus of stiffness and shear strength of a material, but not other properties such as tensile or compressive strength, fracture toughness, or fatigue resistance. Additionally, torsion testing is not suitable for materials with low modulus of stiffness or high ductility, as they may undergo excessive torsion or necking before reaching failure. Additionally, torsion testing is not representative of the actual loading conditions that some materials may experience in service, such as combined or cyclic loading, temperature or environmental influences, or stress concentrations.
Finding a device that meets all your requirements and fits your budget is not an easy task. But Linkotest can help you do just that by getting a high-quality torsion testing machine that fits your budget. We offer a wide range of torsion testing machines in the industry. Our machines are made with high-grade components and are energy efficient. And we will provide various series of torsion testing machines according to your needs and torsion testing machine specifications.
The types of torsion testing machines included in our products include general-purpose, manual, digital display, etc.
- We specialize in providing a wide range of torsion testing machines for quality inspection and certification.
- These machines are suitable for a variety of applications including medical equipment, aerospace, defense, automotive and industrial uses.
- Using these machines, users can perform torsional load tests on their products and analyze material properties or how materials behave under torsional loads.
Although there are various types of torsion testing machines in the market, we suggest that you better consider choosing a reliable manufacturing company for finding effective torsion testing machines.