In Vehicle Movements 📞 (416) 782-7227

• If a seat rocks up and down, will passengers notice? Will they be injured? Will they seek other seats?
• If a crate of food is subject to accelerations and vibrations over its bruising or crushing limit (see results by (A.H.A. Eissa et al) what will the losses be and who will pay? Will the customer return?
• Designing a new car, coach, truck, ship, shipping container? What are the external accelerations acting and how are they inside on equipment, parts, electronics? 
• Our team measures and records those movements. From those records you can  change your seating, your packing, your fleet components.
• On moving vehicles (cars, trucks, trains, ships, airplanes, many movements are repetitive, measured as frequency (number of movements per second) and amplitude (how big movements are). 
• Physical bodies also have certain frequencies at which they respond to excitation. A human body parts tends have a resonant frequency of about 2  Hz to over 90Hz (cycles per second), while the human heart has a resonant frequency of about 1 Hz. 

• When an object is going at a given speed slows down or speeds up, that change is speed with time is called acceleration.  When an airplane takes off, the force due to acceleration pushes you into the seat.
• Acceleration is measured as the change of speed with time or change in velocity with time.  
• Acceleration is the change in speed (for example in kilometers per hour) per second.  
• Conventionally acceleration is reported in ft/sec2, m/sec2, or as a fraction of g (the gravitational acceleration at sea level).  

1 g = 32.17 ft per second^2

1 g = 9.81 m per second^2

• If you want the force acting on an object you multiply its mass by the acceleration.
• If forces are high, accelerations or mass may be high. The larger the force on an object (e.g your heart, your body, fruit, electronic parts, etc. ) the more damage that can be done. 
• Acceleration matters. 
• We experience about 1 g at all times when walking on the surface of the earth, sitting in a plane, or relaxing on a ship. 

• Sea Sickness, a lesser example of why accelerations and movements matter. People doing sea sickness overboard?? 
• If you want the force acting on an object you multiply its mass by the acceleration.
• If forces are high, accelerations or mass may be high. The larger the force on an object (e.g your heart, your body, fruit, electronic parts, etc. ) the more damage that can be done. 
• We experience about 1 g at all times when walking on the surface of the earth, sitting in a plane, or relaxing on a ship. 
• But in the case of a car starting, or a train car bumping along, or a truck driving on a bumpy road, or a ship rolling to and fro, accelerations can cause issues. including damage, for people many symptoms including nausea, falling, etc. 

• Our team uses HBM recording and Jewell  MEMS accelerometers to measure acceleration in all three axes. We can measure at many rates up to 300 Hz.

• So now you engaged a team to measure acceleration of your passenger seat. 
• What does the curve look like and what can it tell you?  
• Above  is a small part of the acceleration versus time curve for the old train coach. 
• One sees the accelerations are about 0.02 g to 0.15 g, that the acceleration curve is full of noise, and that the train jerks. 
• Designers will use the information to design suspensions, fixes, and seat level changes to enhance passenger comfort.

• Here are some typical vibrations and acceleration numbers. 

Where                           g

Sea Level                       1 

Airline at 35000 feet    0.99

Car taking off                0.3

Sprinter                          0.3