To keep up with increasing vibration and shock testing demand, DES added a brand new Unholtz-Dickie Electro Dynamic (ED) Shaker Test System. The shaker is a model SAI30F-S452/ST system with slip table to perform vibration and shock testing along 3 axes. This gives DES additional vibration and shock testing capability and also will help us turn your projects around faster.
Continue reading DES Adds New Unholtz-Dickie Vibration Test System →
Mass Air Flow Sensors (MAFS) are used to measure the mass flowrate of air entering engines in newer model cars. The mass air flow information is transmitted to the engine control unit (ECU) to balance and deliver the correct amount of fuel mass to the engine. These sensors operate in a very harsh environment, a car engine compartment! Testing their reliability and proving their durability is a very difficult task.
DES was awarded multiple contracts to perform combined temperature and vibration reliability testing of Mass Air Flow Sensors from various automotive part manufacturers and from a major auto parts supplier.
Continue reading Case Study: Combined Temperature & Vibration Testing of Automotive Mass Air Flow Sensors →
Vibration testing can be a complicated process. We have created this questionnaire to help make communication between the vibration test lab and customer more efficient. The questionnaire allows us to capture all the pertinent facts about your test requirements. Providing the information below will help us provide an accurate quotation and to perform a successful vibration test. We can help you with answering the questions if needed. Many engineers, not familiar with vibration and shock testing, a subject not taught by universities, may wish to further their education. May we respectfully suggest that you visit http://equipment-reliability.com/training-calendar/vibration-and-shock-testing/ for vibration and shock training courses.
Continue reading Vibration Testing: A Questionnaire for Clients →
First we should answer, what is a pyroshock or a pyrotechnic shock? Both pyroshocks and pyrotechnic shocks are the same thing. A pyroshock occurs when explosive events are used to separate the stages of rockets or missiles, or from a ballistic impact to a structure by a projectile. When a pyroshock occurs, a stress or shock wave propagates through the structure and into the electronic equipment contained within the structure.
Pyroshocks are unique shocks that have high G-level, high frequency content with very little velocity and displacement change during the shock. The frequency range of a pyroshock is usually 100 Hz to 10,000 Hz or greater. Pyroshocks have a very short duration of usually less than 20 milliseconds. The acceleration time history of a pyroshock approximates a combination of decaying sinusoids as shown in Figure 1.
Continue reading What is Pyroshock Testing? →
Random Vibration Testing is one of the more common types of vibration testing services performed by vibration test labs. A primer containing a technical explanation on random vibration testing can be found in our blog article Sinusoidal and Random Vibration Testing Primer.
Real world vibrations are usually of the random type. Vibrations from automobiles, aircraft, rockets are all random. A random vibration test can be correlated to a service life if the field vibrations are known. Since random vibration contains all frequencies simultaneously, all product resonances will be excited together which could be worse than exciting them individually as in sine testing. Sometimes random vibrations are mixed with sine vibrations in Sine-on-Random Vibration Testing. Also, a low level of broad band random vibration can be mixed with additional high levels of narrow band random vibrations in Random-on-Random Vibration Testing.
Some common test standards that have specifications for Random Vibration Testing are:
Continue reading Random Vibration Testing →
DES added another larger AGREE Chamber to perform Combined Temperature and Vibration Testing. This gives DES additional capability to perform combined environmental testing on larger products. DES has performed Combined Temperature and Vibration Testing on car engine sensors, helicopter sensors and outdoor heavy industrial products. Some of the test specifications include MIL-STD-810 and General Motors GMW 3172.
The Equipment Capabilities Are:
To learn more about our combined temperature and vibration testing services, visit our website, and be sure to contact us if you would like to find out how our services can work for your products.
Sinusoidal or Sine Vibration Testing is one of the more common types of vibration testing services performed by vibration test labs. See Sinusoidal Vibration Basics to learn more about vibration fundamentals. A primer containing a more technical explanation on sinusoidal vibration testing can be found in our blog article Sinusoidal and Random Vibration Testing Primer. The types of Sinusoidal Vibration Testing are Sine Sweep Vibration Testing, Sine Dwell Vibration Testing, and Sine-on-Random Vibration Testing.
Continue reading Sinusoidal Vibration Testing →
Most vibration test specifications require vibration testing along 3 orthogonal axes. Vibration testing using most ElectroDynamic (ED) Shakers is performed 1 axis at a time. However the orientation of the ED shaker or the Device Under Test (DUT) can be changed to complete testing along all 3 orthogonal axes.
Many ED shakers can be rotated and connected to a horizontal table called a slip table,
Continue reading Three Axis Vibration Testing →
Classical shock testing consists of the following shock impulses: half sine, haversine, sawtooth, and trapezoid. Pyroshock and ballistic shock tests are specialized and are not considered classical shocks. Classical shocks can be performed on Electro Dynamic (ED) Shakers, Free Fall Drop Tower or Pneumatic Shock Machines. The parameters required to define a shock test are peak acceleration expressed in G’s or m/sec^2, shape of the impulse, and duration in milliseconds. A classical shock impulse is created when the shock table changes direction abruptly. This abrupt change in direction causes a rapid velocity change which creates the shock or acceleration impulse.
Classical shocks are applied along one direction and one axis at a time. Most specifications require the product to be shocked in both the positive and negative directions along each axis. If shock tests are performed on an ED shaker, the shaker can reverse polarity and perform the shock along both directions of each axis without rotating the fixture and specimen. When performing shock testing on a shock machine, the machine can only apply shock in one axis and one direction. The fixture and specimen must be rotated to apply shocks along different directions and axes.
A typical shock test setup using a pneumatic shock machine is shown in Figure 1. DES can also perform shock testing using an ED shaker and drop tower.
Continue reading Classical Shock Testing →
We had many interesting test projects at Delserro Engineering Solutions this past month:
The following is a sample of some additional testing projects we have completed recently: