Characterizing the motion or vibration of objects, structures, and systems

PMI provides field measurement services to characterize the motion or vibration of objects, structures, and systems. We have the instrumentation and trained staff to assess the dynamics of almost anything, whether it be a single small object, a large piece of industrial equipment, a piping or HVAC system, or a complete building and soil system. We determine whether vibrations are problematic and, if necessary, help our clients identify cost-effective, robust solutions. Closely linked to these measurement capabilities are PMI’s extensive analytical skills that include finite element, modal, kinetic, acoustic, and other computer modeling techniques.

Our measurement and analysis capabilities include:

• Multi-Channel Data Acquisition

  • Acceleration
  • Velocity
  • Displacement
  • Strain
  • Temperature

• Short and Long Term Measurements

  • Equipment characterization
  • Structural dynamics assessment
  • Compliance monitoring

• Flow Measurement

• Modal Characterization

  • PMI can conduct the measurements necessary to determine the modal characteristics of real systems. We have conducted studies of system ranging from entire multi-story buildings to small components. We use most current hardware and software in conducting these studies.

• Modal Analysis

  • We are equipped to conduct both SIMO (single input multi output) and MIMO (multi-input multi output) modal analyses. For this type of analysis, a known input load is employed.

• Operating Deflecting Shapes

  • Operating deflection shapes are the shapes (and frequencies) associated with the movement of a structure to an external loading condition. Multi-point measurements are used to define the mode shapes and frequencies.

• Damping Assessment

  • Damping assessment based on Modal Analysis and on impact analysis has long been the standard for damping assessment. With large structures such as buildings, bridges or tall stacks, not being able to apply enough load at the proper frequency has limited the accurate measurement of damping. We employ the latest in computational technology allowing the accurate computation of damping based on ambient structural excitation.

• Model Verification

  • Computational mechanics analyses are based on idealized assumptions about the system under examination which are used to develop idealized boundary conditions. The output of the analyses can only be as good as the match between the assumptions and the actual conditions. Measurements of an actual system can be very profitably used to enhance the fidelity of a computational model. Whenever possible, we strongly recommend correlating the computational model with real data.

PMI’s staff includes experts in the fields of stress, vibration, fluid mechanics, thermodynamics and multi-physics analysis. The combination of our analysts’ diverse skill sets and experience allows the measurement, simulation and optimization of almost any component or system. We have conducted measurement and analysis projects in hospitals, laboratories, universities, research facilities, manufacturing facilities, refineries, and power plants in the greater Kansas City area, throughout the United States, and overseas. The measurement periods have ranged from hours to months depending on the project requirements.