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Testing that Reaches the World

Mechanical, Structures, Fatigue, and Load Testing

For over 30 years, Clark Testing’s Mechanical, Structures, Fatigue, and Load Testing Laboratory has been active in static load, fatigue load and dynamic load testing services. Located in Buchanan Michigan, Clark’s structural lab features one of the larger load test substructures commercially available throughout the US. Clark’s structural floor measures 90’ X 30’ and in excess of applying loads up to 1.5 million lbs.

The unique features of Clark’s structural lab enables load testing of large components such as aircraft wing/fuselage sections, rail components, off-highway and on-highway vehicle frames. Along with its load-testing floor, Clark’s lab also includes vertical and horizontal load test frames, strong backs and custom designed test fixtures to meet our customer’s load testing needs.

Combining the unique infrastructure with the flexibility of modular hydraulic power supplies, our engineers are able to utilize MTS and National Instruments data acquisition and control systems to develop load profiles simulating field conditions. Load test profiles are often developed in collaboration with our customers determining the required frequency and amplitude derived from field data or predetermined design requirements. All structural load test programs can be custom configured to adapt to temperature variables.

In addition to static load testing and fatigue load testing Clark’s structural testing lab also specializes in Rollover Protective Structure/Falling-Object Protective Structure testing (ROPS/FOPS) along with and Rotary Fatigue and torsional testing services.

Testing Services

  • Structural, Frames, & Beam Fatigue Testing
  • Certification Testing & Standards Including
    • Fatigue, Performance, & Durability Testing
  • Ultimate Strength & Proof Load Testing
  • Tensile & Compression Testing
  • Dynamic & Static Brake Testing
  • ROPS / FOPS / TOPS Testing
  • Servo-hydraulic Actuator and Control System with linear & torsional capability
  • Complete Vehicle or Individual Component Testing
  • Seat, Seat Anchorage & Seat Belt Testing

  • Suspension, Hitches, & 5th Wheel Testing
  • Failure & Fatigue Analysis
  • Field Duty Cycle & Accelerated Lab Fatigue Testing
  • Experimental Stress Analysis
  • Strain Gaging, Stress Coat
  • Custom Testing Programs
  • High Speed Data Acquisition
  • Product Comparison & Benchmark Testing
  • Forensic & Litigation Testing
  • On-Vehicle Performance, Prototype Testing & Efficiency Studies.
  • Long Term Testing Capability


Clark’s structural laboratory provides ROPS, FOPS & TOPS testing services in accordance with SAE J/ISO 3471 to qualify structures and cabs typically installed on almost any type of operator driven or stationary machinery. These ROPS, FOPS, & TOPS tests insure the protection and safety of operators from a rollover (ROPS), tip over (TOPS) and a falling object (FOPS). Clark Testing has facilities and capabilities to perform destructive testing of large off-road equipment requiring extreme loads up to 1 million pounds.

Rotary Fatigue

Our Rotary Fatigue Laboratory at Clark Testing can conduct beam and torsional fatigue testing of metals at high and low frequency. Our Rotary Fatigue Testing Laboratory can generate high cycle fatigue on components with large diameter and varied lengths including rotations from 30° to 90° rotation. Repeated cyclic loading will cause fatigue and stresses first creating microscopic cracks that propagate to failure at the roots of the cracks to yield during cyclic aging. Shafts, rods, pipe, studs, and threaded connectors are especially prone to this failure mode.

Fatigue Load

Clark’s structural laboratory provides fatigue load testing. Fatigue Load Testing is the cyclic application of force onto a part or assembly under various load, frequency, and environmental conditions to understand the lifespan of the part. This can be helpful during the development of a new part for it to be approved for use, or in periodic QA checks of production parts. Fatigue load testing often ends when the part cracks, cannot meet the performance requirements, or completely breaks. One of the main goals of fatigue testing is the development of an S-N curve to be able to statistically predict the performance of a part under various stress levels.

Proof Load

Clark’s structural laboratory provides proof load tesitng.A proof load test is a type of non-destructive test where the component is loaded to a determined load and held there in order to verify that the component can withstand the load. The load requirement is usually two to six times the normal operating load, and the failure criteria usually include cracking or deformation of the part.

Proof testing can verify the maximum load safety factor is being met and help meet other quality and safety specifications.

Ultimate Load

Clark’s structural laboratory provides Ultimate load testing. An ultimate load test is a type of destructive test where the component is loaded until failure. An ultimate test can help determine the load at which a component will start to deform plastically or irreversibly. This information is particularly useful for engineers in designing parts and choosing materials. This testing can also help refine and validate FEA models and find flaws in manufacturing processes. Ultimate testing can determine the maximum load safety factor is being met and help meet other quality and safety specifications

We work closely with you to validate engineering, ensure quality, analyze products and qualify equipment while supporting the time constraints and product cycles that are vital to your success.

Paul Heffernan, CEO of Clark Testing