Dry Spring Testing Machine (DSTM)

Dry Spring Testing Machine (DSTM)

The Development and Quality Monitoring of resilient, highly stressed automotive components such as springs requires testing that represents actual vehicle conditions as accurately as possible. There are some essential test areas when determining the quality of spring steel, for example, fatigue strength and setting behavior under realistic load and environmental conditions.

Based on these requirements, IABG offers a spring testing machine capable of performing fatigue tests in normal laboratory atmosphere. Thus allowing the determination of spring fatigue strength while reducing both time and cost.

Advantages of the IABG spring testing machines

  • Energy efficiency by utilising the principles of resonance in tests
  • Reliability and low maintenance
  • Designed to exclude all external forces and vibrations
  • Testing with parallel and circular deflection
  • Tests with original spring seats in installation position
  • Integrated measurement of spring characteristic curves and spring setting
  • Optional application of abrasive media to spring seat
  • Software-based testing, documentation and evaluation
  • Accepted by all leading car manufacturers
  • Compliant with German OEM standards (AK-LH 07) of springs and stabilizer bars

 

Relevant influences on Springs

  • Mechanical demands from
    • Spring compression
    • Axle kinematics
  • Damage to the surface and coating through
    • Abrasion caused by spring coil contact
    • Stone impact
    • Corrosion

Experimental verification

  • „„Pre-damage caused by stone impact
  • „„Corrosion in alternating cycle tests developed by the German Association of the Automotive Industry (Verband der Automobilindustrie, VDA)
  • „„Optional tests with simulated compression kinematics on full axle configuration
  • „„Tests with original spring seats in installation position
  • „„Fatigue test with cylic load and with fixed or variable amplitudes
  • „„Abrasive wear simulation
  • „„Statistical validation through systematic testing and a sufficient number of test items

    Technical data

    • Test specimens:
      parallel or circular deflection on springs of all types
    • Max. permissible load per test position:
      Fmax = 40 kN
    • Number of possible test specimens per test:
      2, 4, … limited by Fmax
    • Stroke (displacement control): S = 10 to 250 mm
    • Max. Spring length: L0 = 600 mm
    • Test frequency:
      fo = 0,47 √(n·R) [Hz] = 2 to 25 Hz
      n = Number of test specimens tested
      R = Spring constant [N/mm]
    • Weight / measurements of machine:
      3 tons, L = 1800 mm, W = 2000 mm,
      H = 2500 mm (additional space required for:
      operator panel, and hydraulic aggregate)