Component Tests

Introduction

There are many different types of part and component tests. Some are to characterize the structural performance of the part and some are to verify the performance of an associated finite element analysis.

A Few Experiments at Axel:

  • Relaxation and Thermal Recovery Sequence
  • Bushing and Mount Characterization
  • Wire Tests
  • Load Deflection Tests
  • Axial + Torsional Testing
  • Impact Experiments


  • Relaxation and Thermal Recovery Sequence

    A one day physical testing sequence has been developed to provide insight into the early effects of elevated temperature on compressed elastomers. By compressing an elastomeric material specimen (or actual elastomeric part) and holding it at a constant strain, the effects of time and temperature on the reaction force are measured. In particular, the reaction force at sub-ambient temperatures after first being subjected to an elevated temperature can be indicative of the changes that occur in the elastomer while at the earlier elevated temperature.

    Graph of a typical thermal relaxation and recovery sequence.
    Planar Tension (Pure Shear ) with Laser Extensometer


     

    Schematic of a test instrument that performs thermal relaxation and recovery sequences on sealing parts and materials.
    Relaxation Recovery Test Setup



    Bushing and Mount Characterization

    The static and dynamic characterization of bushings, mounts and other vibration isolation devices is determined as a function of loading rates, frequencies and temperatures. The information from these tests is sometimes used in kinematic software such as ADAMS or for basic product performance verification.

    Graph of dynamic stiffness as a function of mean strain  and amplitude and frequency.
    Mean Strain Effect on Mount Stiffness

     

    Image of a rubber body mount in a mechanical test fixture.
    Dynamic Bushing Characterization

    Wire Tests

    Structural testing of fine wire for the purpose of obtaining static stress and strain data or cyclic fatigue data can be challenging. Careful gripping and strain measurement are critical parameters for success.

     

    Graph of load deflection for an automotive body seal.
    Physical Test Results from Load and Unload Straining of a Shape Memory Alloy Wire at 37C

     

     

    Image of extruded seal under various levels of compression.
    Wire Specimen with Optical Strain Measurement Tags



    Load Deflection Tests

    The examination of the basic load deflection characteristics of components can be critical to understanding the complex behavior of components. It may also be performed for the purpose of verifying results generated using analytical tools. The use of imaging systems along with basic load deflection tests can provide information regarding the relationship between the part shape, the structural properties and the analytical model.

     

    Graph of load deflection for an automotive body seal.
    Load Deflection of an Automotive Primary Seal under Repeated Loads

     

     

    Image of extruded seal under various levels of compression.
    Side Profile Images of an Automotive Seal



    Axial + Torsional Testing

    It can be valuable to examine parts and materials in a combined axial and torsional stress and strain condition. The system at Axel is capable of a combined 10 kN axial force and 100 N-m torsional force.

     

    Image of a biaxial test frame capable of axial and rotational loading.
    Combined Axial and Torsion Dynamic Test System



    Impact Experiments

    By dropping a weight or swinging a pendulum, impact experiments allow us to characterize the response of materials and parts to predefined energy input. The controlled parameters are mass and velocity. These experiments are a particularly useful way to verify material models that were calibrated using constant strain rate experiments.

    Pendulum tester.
    Pendulum Test System

     

    Image of a drop tower.
    Drop Weight Test System