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Interface Supports Wind Tunnel Testing

In the development of an airborne vehicle, like a plane or helicopter, wind tunnel systems are used to gather data across a variety of tests related to the aerodynamics of the vehicle’s design. Whether an object is stationary or mobile, wind tunnels provide insight into the effects of air as it moves over or around the test model. Interface is a supplier of measurement solutions used for aircraft and wind tunnel testing.

Wind tunnels are chambers that test small scale model versions of full systems, or in some cases, parts and components, depending on the size and capabilities of the wind tunnel. They work by allowing the engineers to control airflow within the tunnel and simulate the types of wind force that airplanes and other aircraft will experience in flight. Wind tunnels are also used for testing automobiles, bicycles, drones and space vehicles.

By taking careful measurements of the forces on the model, the engineer can predict the forces on the full-scale aircraft. And by using special diagnostic techniques, the engineer can better understand and improve the performance of the aircraft.

The process for measuring the force and how it reacts to this force works by mounting the model in the wind tunnel on a force balance or test stand. The output is a signal that is related to the forces and moments on the model. Balances can be used to measure both the lift and drag forces. The balance must be calibrated against a known value of the force before, and sometimes during, the test.

Interface’s strain gage load cells are commonly used in wind tunnel testing due to their quality, accuracy and reliability. The instrumentation requirements often depend on the application and type of test. The range of options for both load cells and instrumentation vary based on scale, use, cycle counts, and data requirements.

Instrumentation used in wind tunnel testing can be as simple as our 9325 Portable Sensor Display to a multi-channel data acquisition system. Interface analog, digital and wireless instrumentation solutions provide a range of possibilities. As is the case, wind tunnel testing is typically very sensitive. It is important to calibrate the instrumentation before each test to measurement accuracy.

Types of Wind Tunnel Tests Using Force Measurement Solutions

  • Lift and drag: Load cells are used to measure the two most significant forces that impact aircraft design. Lift is the force that acts perpendicular to the direction of airflow and keeps the craft airborne. Drag is the force that acts parallel to the direction of airflow and opposes forward motion.
  • Side force: This force acts perpendicular to both the direction of airflow and the lift force. It is caused by the difference in pressure between the upper and lower surfaces of the aircraft.
  • Moments: Moments are the forces that act around a point. The most common moments measured in wind tunnels are the pitching moment, the yawing moment, and the rolling moment.
  • Stability and control: Tests conducted to measure the stability and controllability of an aircraft are commonly using force measurement solutions for aircraft design changes or integrating new parts into an existing model.
  • Performance: Particularly important with new designs, engineers use these tests to measure the simulated flight performance under maximum speed, range and fuel efficiency.

The specific tests that are conducted in a wind tunnel depend on the project requirements.

Multi-Axis Sensors for Wind Tunnel Testing Applications

In measuring the forces of a wind tunnel test, multi-axis sensors offer the perfect solution for collecting as much data as possible across every axis, giving the engineer a more complete picture on the aerodynamics of the plane. In fact, Interface has supplied multi-axis load cells for use in several wind tunnel testing applications, for OEMs, testing facilities and part makers.

We offer a variety of multi-axis options including 2, 3 and 6-axis standard and high-capacity configurations depending on testing and data requirements of the user. These sensors can precisely measure the applied force from one direction with little or no crosstalk from the force or moment. Interface products provide excellent performance and accuracy in force and torque measurement.

To match the demands of the volumes of data available using multi-axis sensors in wind tunnel testing, Interface often provides several data acquisition instrumentation solution along with our BlueDAQ software.

Wind Tunnel Test Application

A major aerospace company was developing a new airplane and needed to test their scaled model for aerodynamics in a wind tunnel, by measuring loads created by lift and drag. Interface Model 6A154 6-Axis Load Cell was mounted in the floor of the wind tunnel and connected to the scaled model by a stalk. The wind tunnel blew air over the scaled model creating lift and drag, which was measured and compared to the theoretical airplane models. The output of the 6-axis sensor was connected to the BX8-AS Interface BlueDAQ Series Data Acquisition System, which was connected via USB cable to a computer. Using this solution, the company was able to analyze the collected data and made the necessary adjustments in their design to improve the aerodynamics of their theoretical airplane models.

Interface supports wind tunnel testing and all uses of force measurement in the advancements in aeropspace.

Wind tunnel testing is critical to the aircraft industry, as well as other industries like automotive and space. Interface has been providing multi-axis sensors and strain gage load cells to industry leaders and wind tunnel operators. We understand the unique needs of this type of testing and the instrumentation options that work best with our high-accuracy sensors. We also can work to provide custom solutions, load cells for use in extreme environmental conditions. Contact us to get the right solution for your specific testing program.

Additional Resources

Aircraft Wing Fatigue App Note

Airplane Jacking System

Interface Airplane Static Testing Case Study

Taking Flight with Interface Solutions for Aircraft Testing

Aircraft Yoke Torque Measurement

Aircraft Screwdriver Fastening Control App Note

Interface’s Crucial Role in Vehicle and Urban Mobility Markets

Rigging Engineers Choose Interface Measurement Solutions

 

Interface Multi-Axis Sensor Market Research

Recently, Interface commissioned an independent research report on multi-axis sensors demand and use cases. This is a product line that Interface has made significant investments in as more customers require increased load cell functionality and additional source data from their force sensors. The research results confirm that the current demand is in fact expanding worldwide, and the overall users and market size is expected to grow by double digits over the next six years.

Included below is a brief overview of the state of the multi-axis, as well as an explanation of their overall purpose and why the growth of this type of test and measurement device continues to increase in popularity. We will also continue to break out the results of this research paper, so tune into the InterfaceIQ blog for more multi-axis research content. To learn more about these advanced sensors, view our ForceLeaders webinar Dimensions of Multi-Axis Sensors.

Multi-Axis Sensors Market Overview: The rise of IoT and Industry 4.0 had enabled automation. Machines continue to get smarter and can make split-second decisions using real-time data. Force measurement plays a key role in this transformation. Load cells that are tracking performance and reliability have more insights than ever before. They will continue to grow in their accuracy and capabilities. Load cell and sensor technologies are being used to identify precisely when and where something went wrong on a production line. Load cells will be growing in playing a key role in making production lines more efficient, less reliant on human resources and less costly.

There has been increased need for multi-axis sensors that measure and collect data points on up to six axes. Multi-axis sensors were invented because of the increased requirements for data, both in testing and during actual product use. And this is not slowing down anytime soon. Over the next decade, load cells will continue to keep up with the demand to handle more measurement data points. More sensors will need to be packed into a single device to collect more data with less equipment.

Five Key Take-Aways from Interface’s Multi-Axis Market Research:

  1. There is a growing requirement for high-performance sensor fusion of multi-axis sensor systems to enable the newly emerging technologies and highly demanding applications.
  2. Advancements in technology enabling effective components at a lighter and smaller size, such as the swift rise of unmanned vehicles in both the defense and civil applications and the increasing applications based on motion sensing, are the factors driving the multi-axis sensor use cases for testing and to embed into products.
  3. Digitizing force sensors is another trend changing our product innovators and manufacturer’s designs of machines and equipment through advanced measurement data. Many have strongly invested in more advanced digital electronics to efficiently harvest and store more data. Revolutions in industries and technologies is the dominant trend in force measurement, not to mention the entire manufacturing and engineering industry. Harnessing big data enables product users to remotely monitor assets and increase use of analytics.
  4. With network-connected force measurement through sensors and instrumentation, OEMs have greater control over testing and product development. Equipment using multi-axis sensors to track performance and reliability provide valuable data on how equipment is performing and predict when machines need maintenance.
  5. Global machine makers and equipment builders want smaller force sensors they can permanently install in the products. Smaller, wireless sensors are easier and less expensive to install. As more industrial networks are created to share higher-quality data, more and more sensors will be added to these machines.

What: Multi-axis sensors allow the user to measure forces and torques, which occur in more than one spatial direction, as with measurements in x- and y-direction. This allows manufacturers to obtain more data on a wider variety of axes, allowing them to make better design decisions and ultimately improve the product quality. A crucial focus is force measurement in manufacturing, where force transducers are frequently used to determine the force for weight measurement or in the process of production.

Why? Data-driven test and measurement is at the forefront of product development, especially in highly regulated markets like aerospace, automotive, medical, and industrial. One of the most significant applications for multi-axis sensors is seen in manufacturing facilities who want to integrate more autonomy and robotic processes. The goal is to streamline logistics procedures and reduce human errors and workplace accidents. The report also found that there is a great deal interest for last-mile delivery robots, either on the ground, on the sea or drones in the air.

Interface’s Role: Interface multi-axis load cells are ideal for industrial and scientific applications. They are used by engineers and testing labs in various industries and market segments including aerospace, robotics, automotive, advanced manufacturing, for medical devices and research. Our products designed to provide the most comprehensive force and torque data points on advanced machinery. With our industry-leading reliability and accuracy, these multi-axis sensors can provide the data our customers need to ensure performance and safety in their product design.

In fact, their unique capabilities are helping the medical industry optimize prosthetic designs and usability standards with multi-axis sensor testing. The automotive industry is using Interface’s multi-axis products in wind tunnels, and the military is using them to test the center of gravity in aerospace applications.

Here are a few applications use cases that show how multi-axis is advancing products in multiple industries:

Wind Tunnel

Seat Testing Machine

Friction Testing

Industrial Robotic Arm

Ball and Socket Prosthetic

Prosthetic Foot Performance

Syringe Plunger Force Measurement

Research was conducted independently by Search4Research.

Dimensions of Multi-Axis Sensors Virtual Event Recap

The Interface ForceLeaders hosted forums are designed to answer frequently asked questions from testing engineers and product designers about new technologies and uses cases. In our recent virtual event, Dimensions of Multi-Axis Sensors, we discussed the considerations for these types of sensors, the test and measurement benefits, products Interface offers and various applications.

Interface recognizes that there are growing demands for multi-axis sensors.  In our hosted event, Interface’s Brian Peters kicked-off the conversation by highlighting benefits and reasoning for the use of these types of sensors, including answering some common questions. We’ve provided a recap of the event below or you can watch the event here https://youtu.be/zua1lvTh488.

What is Unique about Multi-Axis Sensors?

Multi-axis sensors have additional bridges to provide output signals for varying axes or types of mechanical loading. They are designed to measure a multitude of forces and moments simultaneously with a single load cell sensor. Fundamentally similar to other force and torque sensors with strain gage bridges bonded to machined “flexures,” each bridge typically defines a measurement axis. 

There are multiple configurations of 2, 3, or 6-axis options.

  • Axial + Torque
  • Axial + Shear
  • Axial + Moment
  • All 6 degrees of freedom

Should You Use Multi-Axis Sensors?

The largest factor to consider is the accuracy of your test model. In many test applications using standard load cells we often notice side or eccentric load, which can skew your data. While many Interface load cells, particularly mini load cells, have been designed to reject indirect loads, nothing can handle side and eccentric loads quite like a multi-axis sensor. Dedicated multi-axis designs are typically more balanced axis capacity limits with discrete signal outputs. Composite signal outputs are common in 6-axis models.

What are the Benefits of Multi-Axis Sensor Technology?

There are a number of benefits to using multi-axis sensors in addition to accounting for and accurately measuring or rejecting side and eccentric load. These benefits include:

  • Consolidate measurement signals, conserve test space
  • Measure unwanted system crosstalk
  • Quantify reaction loads through test article on “non-measure” side 
  • More successful fatigue testing through setup and load verification
  • More data, more understanding, more complete picture

What Considerations Should Engineer Make When Using Multi-Axis Sensors?

If you’ve made the decision to utilize a multi-axis sensor in your test model, please note the following considerations:

  • System-level loads and geometry
  • Maximum loading conditions
  • Chosen capacity is adequate for measurement loads as well as potential peak or extraneous loads
  • Choosing the right sensor based on primary axis measurements

Interface Multi-Axis Sensor Products

Ken Bishop details various types of multi-axis sensor technology from Interface during the highlighted ForceLeaders event you can watch here.  Interface offers a wide range of multi-axis sensors, including 3-axis, 6-axis, axial torsion and 2-axis versions. The product options give you the ability to measure forces simultaneously in three mutually perpendicular axes, with the 6-axis load cells also measuring torque around those axes.

AXIAL TORSION LOAD CELLS

Interface’s axial torsion load cell is used for measuring both torque and force in a single sensor. Typical applications of its axial torsion transducer include bearing test and material test machines. The features of our axial torsion load cell include minimal cross talk, extraneous load resistance, and the load cell is fatigue rated. Customers can also add the following options: an integral cable, compression overload protection, and connector protectors.

2-AXIS LOAD CELLS

The Interface 2-Axis load cells can measure in two directions, X and Y simultaneously. It is commonly used in applications where dual-axis measurement is important in design and testing. They are effective for applications that measure lateral forces and the narrow design fits into compact areas.

2-Axis Interface Products:

3-AXIS LOAD CELLS

Interface’s 3-axis load cell measures force simultaneously in three mutually perpendicular axes: X, Y, and Z – tension and compression. Each axis provides a unique mV/V output and requires no mathematical manipulation. The 3-axis load cell is built to minimize eccentric loading effects and crosstalk between axes. We offer five different models in its 3A Series 3-axis load cell designed for a wide variety of capacities. They are compact in size, provide 3 full bridge mV/V outputs with an IP68 option.

3-Axis Products:

6-AXIS LOAD CELLS

Interface’s 6-Axis Load Cell measures force simultaneously in three mutually perpendicular axes and three simultaneous torques about those same axes. Six full bridges provide mV/V output on six independent channels. A 36-term coefficient matrix is included for calculating the load and torque values in each axis. An 8-channel amplifier with a USB PC interface is also available which simplifies data analysis. The company offers five different models of 6-axis load cells for a wide variety of capacities. In the end, they provide more data, accuracy, are very stiff and cost-effective for a wide range of testing options.

6-Axis Products:

Keith Skidmore, an application expert at Interface, outlined a number of use cases spanning across multiple industries. They included testing programs using multi-axis sensors in automotive, medical, aerospace and defense, consumer packaging and more. Some of the application notes discussed during this recorded event include:

  • Wind tunnel testing
  • Aerospace structural and fatigue testing
  • Computer model validation
  • Friction testing
  • Medical device: ball socket testing
  • Prosthetics
  • Robotic arm
  • Hydrofoil
  • Seat testing
  • Center of gravity

Be sure to watch the YouTube video below to gain insight into some of the most frequently asked questions about multi-axis sensors.

We had a great time introducing our audience to the possibilities of Interface Multi-Axis Sensors. If you are interested in watching the video on demand of the webinar, you can click on the link below to watch the presentation in its entirety.