CHAPTER FOUR

PRINCIPALS OF ULTRASONIC MEASUREMENT

4.1 Time versus thickness relationship

Ultrasonic thickness measurements depend on measuring the length of time it takes for sound to travel through the material being tested. The ratio of the thickness versus the time is known as the sound velocity. In order to make accurate measurements, a sound ve locity must be determined and entered into the instrument.

The accuracy of a thickness measurement therefore depends on having a consistent sound velocity. Some materials are not as consistent as others and accuracy will be marginal. For example, some cast materials are very granular and porous and as a result have inconsistent sound velocities.

While there are many different ultrasonic techniques to measure thickness, which will be discussed below, all of them rely on using the sound velocity to convert from time to thickness.

4.2 Suitability of materials

Ultrasonic thickness measurements rely on passing a sound wave through the material being measured. Not all materials are good at transmitting sound. Ultrasonic thickness measurement is practical in a wide variety of materials including metals, plastics, and glass. Materials that are difficult include some cast materials, concrete, wood, fiberglass, and some rubber.

4.3 Range of measurement and accuracy

The overall measurement capabilities, based on the wide variety of materials, is determined by the consistency of the material being measured

The range of thickness that can be measured ultrasonically depends on the material as well as the technique being used and the type of transducer. Thickness measurements can be made from a minimum of 0.010 inch to 9.999” in steel. However, the maximum attainable thickness is much less for more attenuative materials (materials that absorb sound).

Accuracy, is determined by how consistent the sound velocity is through the sound path being measured, and is a function of the overall thickness of the material. For example, the velocity in steel is typically within 0.5% while the velocity in cast iron can vary by 4%.

4.4 Couplant

All ultrasonic applications require some medium to couple the sound from the transducer to the test piece. Typically a high viscosity liquid is used as the medium. The sound frequencies used in ultrasonic thickness measurement do not travel

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Dakota Digital CMX Chapter Four Principals of Ultrasonic Measurement, Time versus thickness relationship, Couplant
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CMX specifications

Dakota Digital CMX series represents a cutting-edge advancement in the world of digital instrumentation, designed specifically for automotive enthusiasts and restorers seeking to enhance their vehicle’s dashboard aesthetics and functionality. Characterized by its sleek appearance and intelligent design, the CMX offers a multitude of features that cater to modern demands while preserving the classic vehicle feel.

One of the standout features of the Dakota Digital CMX is its customizable display. The series provides an array of screen layouts and color schemes that allow users to personalize their instrumentation according to individual preferences. This flexibility not only enhances the visual appeal but also aids in quickly obtaining critical information at a glance, improving overall driver convenience.

The CMX is equipped with state-of-the-art technology, including high-definition OLED displays that ensure crisp visibility in all lighting conditions. This technological advancement makes the instrument panel not only easy to read but also optimally functional in both bright sunlight and low-light situations. The ambient light sensors adjust brightness automatically, promoting user comfort.

Another defining characteristic of the Dakota Digital CMX is its comprehensive data logging and diagnostic capabilities. Integrated advanced sensors enable real-time monitoring of various vehicle metrics, such as speed, RPM, fuel level, and engine temperatures. This feature aids users in maintaining their vehicle's performance and in diagnosing potential issues before they escalate into more severe problems.

The CMX series supports numerous vehicle types, with a compatibility range that includes classic muscle cars, street rods, and even motorcycles. Furthermore, it incorporates Bluetooth technology, allowing users to connect their smartphones for further customization and real-time data analysis via an associated app.

Installation is designed to be user-friendly, making it accessible even for those with limited automotive knowledge. The system typically utilizes plug-and-play wiring harnesses, simplifying the overall setup process. Additionally, the CMX series is engineered to withstand the harsh environments often found in automotive applications, ensuring durability and longevity.

In summary, the Dakota Digital CMX series exemplifies a harmonious blend of modern technology and classic style. With customizable displays, advanced diagnostics, excellent visibility, and robust construction, it is a top choice for those looking to elevate their vehicle’s instrumentation. The CMX not only provides essential information but also transforms the driving experience, making it both informative and enjoyable.
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