Testing At Transtex: Experimental Modal Analysis

Have you ever wondered why our brackets are positioned where they are along our aerodynamic skirts? Well, it wasn’t by random selection! Transtex engineers always go the extra mile to ensure that every inch of our product, brackets included, is tested rigorously for optimal stability on the road.

So let’s go back to our original question: why are brackets positions where they are along the skirt panel? Consider the purpose of the bracket; not only is it meant to attach the skirt to the trailer, it is also meant to stabilize the system under all road conditions. This allows it to withstand road vibrations, thus improving the endurance and life expectancy of the skirt.

Transtex tests the aerodynamic skirts using the Experimental Modal Analysis to determine the natural frequencies of the structure. This allows our engineers to detect the optimal bracket placement locations across the panel.

Experimental Modal Analysis is the study of the dynamic properties of an object under vibration. In other words, it is a non-destructive test method that studies how an object responds to a changing amplitude of vibrations. To conduct the Experimental Modal Analysis, an impact hammer with a force sensor at the tip is placed on one side of the skirt to create the necessary vibrations. An accelerometer is attached to the opposite side to measure the amplitude of the oscillations, i.e. the back and forth movement of the skirt. The impact hammer then moves, or “roves,” across the skirt panel following a predefined pattern that is based on computer analysis.

During a road test, Transtex measures the critical oscillation frequencies using the accelerometer. The roving hammer test determines the critical and natural oscillation frequencies of the skirt panel allowing our engineers to locate the optimal placement for the brackets, thus increasing the maximum road life span of the skirt panels.

Aerodynamics And You: Coast Down Testing

For the last two weeks we have been keeping you informed of the most popular methods of aerodynamic testing. Keep in mind that at high speeds, aerodynamic drag is to blame for approximately 25% of your truck’s fuel losses! Coast Down testing is another aerodynamic testing method used to measure aerodynamic drag. Read below to learn more!

Coast down testing is used to calculate the resistance caused by drag that a vehicle in motion encounters. Drag pushes the vehicle in the opposite direction of its motion, thus creating resistance. In order to combat such resistance, the vehicle’s engine must work harder. So, by reducing drag, a truck’s engine requires less power to push forward, which in turn requires less fuel. The test is conducted on a flat stretch of road while the vehicle is decelerating. Many factors must be taken into account before starting a coast down test. These include the mileage of the vehicle, ambient temperatures, wind, barometric pressure, and much more. Once the vehicle reaches a speed of almost 75mph, it is put to neutral and is allowed to coast until it stops.

Aerodynamics And You: Computational Fluid Dynamics (CFD)

Last week we mentioned the importance of aerodynamic solutions for your fleet. Recall that at high speeds, aerodynamic drag is to blame for approximately 25% of your truck’s fuel losses!

Computational Fluid Dynamics, or CFD, are another popular aerodynamic testing tool. CFD are mathematical computer simulations of the mechanical behavior of a fluid, in this case air, and how it flows around a vehicle. Testing involves a 3D model of the latter, and finite element simulation, or in other words simulation of how air flows around the 3D model. One important advantage of CFD is that is allows us to test a system without having to create a physical model. It can be used as a virtual lab. Furthermore, CFD is a powerful visualization tool. It creates a visual representation of air and how it flows, whereas air cannot be seen in the real world.  Once multiple simulations have been completed, the next step is to validate the results by attempting to replicate them in a real-world situation or in a wind tunnel. This method can be used during new product development in order to test and optimize a new concept.

Stay tuned for next week’s informational post on aerodynamic testing!

Aerodynamics And You: Wind Tunnels

Why are aerodynamics important to your fleet? Well consider this: at high speeds, aerodynamic drag is to blame for approximately 25% of your truck’s fuel losses! Through aerodynamic testing and aerodynamic solutions, such as the Transtex Trailer Skirts, we aim to reduce that 25% fuel loss as much as possible.

Wind tunnels are one of the leading tools used for aerodynamic testing. More specifically, they are used to gather drag reduction measurements. Finding new aerodynamic solutions is crucial to reducing the 25% fuel losses caused by drag. This is where wind tunnel testing comes in handy; it proves in a quantifiable way the drag reduction abilities of aerodynamic products such as the Transtex single skirt kit. Combined with moving ground technology, wind tunnels allow testers to control the environment in which the model is observed, letting mimic real-world factors such as wind speed, and wind direction.  Although wind tunnel testing can be conducted on full scale trucks and trailers, it is most common to use a scale model replica of the vehicles. This is due to sizing issues and unavailability of a moving ground large enough for a full scale truck and trailer. Some may worry about the accuracy of results gathered from scale models, but research has proven that reasonable results are still attained with the smaller replicas.

Stay tuned for next week’s informational post on aerodynamic testing!

Curious About How We Test Our Skirts?

Transtex prides itself on providing you with the number one aerodynamic skirt on the market. Our products go through rigorous testing to ensure that you get nothing but the best.


Aerodynamic skirts are placed on a shaker rig, which imitates their setup on a trailer. They are then subjected to 70 consecutive hours under a random vibration load, at ASTM D4728 Assurance Level 1, in order to replicate vibrations caused by road conditions. The purpose of this test is to do a life assessment of the skirt in a realistic and controlled environment.


The aerodynamic skirt is subjected to deformation in order to determine how it reacts to body and ground interference, like accidents for example. Destructive testing allows us to observe any failure or damage to the brackets and skirt combination. When combined with computer simulations, the data gathered helps us determine possible failure locations across the skirt and brackets.


A flexural test is performed under various conditions, such as hot and cold temperatures. The purpose of this test is to determine the forces and deflections beyond elastic deformation. Note that elastic deformation is a temporary shape change that reverses once force is removed. Our Blue Bracket, for example, is designed to stay within the elastic region. Furthermore, our kits are also tested for stability on the road in order to measure the displacement amplitude of the side skirt assembly under road vibrations.

Transtex Is A Proud Member Of The ATA, TMC, WIT, And TCA

Transtex is proud to be a member of American Trucking Association, Technology & Maintenance Council, Women In Trucking, and Truckload Carriers Association. We believe in supporting and improving all aspects of the commercial vehicle industry, including safety, equipment, sustainability, and increasing opportunities for women.

Transtex Is Looking For New Talented Engineers To Join Our Team!

The Transtex family is growing! Are you dynamic, innovative and looking for the right challenge that will help you and our team flourish? We are looking for a Support engineer and a Product Development Engineer to join our Montreal office. Innovation, teamwork, and integrity are crucial values that we live by, and we encourage growth and communication in all facets of our work. If you believe that you share the same passion and drive as the Transtex family, then we encourage you to apply!

Transtex Supports Women In The Industry

We are proud to announce that we are official members of the Women in Trucking Association! Last fall, our team joined the Association and participated in the Accelerate! Conference of 2016 where we learnt about current issues women face in the industry, emerging trends, and various approaches to diversify the workforce. Overall, the conference was a success, and we enjoyed every minute of it.Women in Trucking is a non-profit North American organization that encourages the employment of women in the trucking industry, promotes their accomplishments and works to minimize obstacles faced by women in the trucking industry.

Proven Results

Trailer side skirts provide an aerodynamic benefit that is nearly impossible for motor carriers to ignore. Initially, EPA SmartWay ratings and CARB compliance requirements gave operators the impetus to begin considering skirts. Today, paybacks of 6 to 15 months have caused most carriers to begin installing trailer skirts. SAE Type II testing found fuel savings of up to 7.35 percent for the Transtex design and Wind Tunnel data gave 5 percent.

Carriers can expect anywhere from 4 to 6 percent fuel savings. With more then 400 loyal customers, our users include Averitt Express, Celadon, Covenant Transport, Saia, TCSI-Transland and Werner Enterprises because of our skirt’s unparalleled performance and reliability. Transtex has the highest level of customer satisfaction in the industry.