Intervertebral Fusion Cage Shear Fatigue Tester

Standards:

ASTM F2077

Main applications: 

Performance evaluation: Test indicators such as the fatigue strength, stiffness, and deformation of intervertebral fusion cages under shear loads to assess their overall performance and ability to maintain structural integrity over millions of simulated load cycles. This helps determine if the cage can withstand the shear stresses experienced in the spine without fracturing or excessively deforming.

Quality control: During the production process, use the shear fatigue testing machine to conduct quality inspections on intervertebral fusion cages, ensuring that each batch of products meets the predetermined performance standards and specifications for fatigue resistance under shear. This is critical for maintaining consistent product quality and reducing the risk of implant failure in patients.

R & D support: Provide experimental data support for the research and development of intervertebral fusion cages, helping R & D personnel optimize product design, materials, and manufacturing processes. Testing different cage designs, materials (e.g., titanium, PEEK, novel biomaterials), and manufacturing techniques under shear fatigue helps improve their durability, stability, and overall clinical success rate.

Product Advantages:

The Intervertebral Fusion Cage Shear Fatigue Tester offers significant advantages for assessing the crucial shear fatigue performance of these spinal implants:

Simulates Spinal Shear Loading: Replicates the cyclic shear stresses that intervertebral fusion cages experience in the spine, providing highly relevant fatigue data.

Evaluates Long-Term Durability: Determines the fatigue life and resistance to failure under repetitive shear loads over extended periods.

Critical for Patient Safety: Provides data essential for ensuring the long-term mechanical stability of the implant, reducing the risk of cage subsidence or fracture in vivo.

Supports Regulatory Compliance: Enables testing according to standards like ASTM F2077. which is often required for regulatory approval of spinal fusion devices.

Objective Performance Data: Yields quantitative measurements of fatigue strength, stiffness, and deformation under shear, allowing for objective comparison of different cage designs and materials.

Facilitates R&D and Quality Control: Essential tool for optimizing cage design, material selection, and manufacturing processes, as well as for ensuring consistent production quality.

Product Features:

An Intervertebral Fusion Cage Shear Fatigue Tester is typically a sophisticated dynamic testing system capable of applying controlled shear loads, often as part of a multi-axis loading regimen that includes axial compression, to simulate spinal conditions. Key features include:

A dynamic testing frame (e.g., servo-hydraulic or electrodynamic) with capability for applying cyclic loads in shear and potentially axial directions. Multi-axis systems are often used to simulate the combined loading experienced by cages.

A specialized fixture designed to hold the intervertebral fusion cage and apply cyclic shear loads. This fixture typically involves simulated vertebral body blocks (often made from a rigid polymer or bone substitute material, or sometimes using actual bone) between which the cage is placed and loaded.

Load cells for accurate measurement of dynamic forces in the shear and potentially axial directions.

Displacement sensors or the testing machine's measurement system to record deformation of the cage assembly under cyclic shear and axial loads.

Advanced control system capable of applying complex cyclic loading profiles (e.g., simulating physiological gait or activity) with precise control of load and/or displacement in multiple axes.

A cycle counter to accurately record the total number of load cycles applied.

A data acquisition system to capture load, displacement, and cycle count data throughout the fatigue test.

Sophisticated software for setting up complex fatigue test parameters, real-time monitoring of test progress, detecting sample failure, and analyzing fatigue data (e.g., creating S-N curves, evaluating stiffness degradation).

An environmental chamber or fluid bath designed to enclose the test setup, capable of maintaining physiological temperature (e.g., 37°C) and holding a simulated body fluid (e.g., saline solution) to replicate the in vivo environment.

Safety features such as overload protection, emergency stops, and protective enclosures.

Technical Parameters:

Dynamic Load Capacity (Axial/Shear): (e.g., typically ranging from ±5 kN to ±25 kN or more in axial and shear directions, reflecting expected spinal loads)

Frequency Range: (e.g., up to 10 Hz, 20 Hz, or higher, as specified by the relevant testing standard, e.g., ASTM F2077)

Load Control Accuracy: (e.g., ±1% of set load or better)

Displacement Control Accuracy: (e.g., ±1% of set displacement or better)

Type of Loading: (Compression-Shear, often with adjustable ratios of axial to shear load)

Maximum Number of Cycles: (Designed for long-term testing, e.g., up to 5 million or 10 million cycles as per standards)

Actuator Stroke (Axial/Shear): (Sufficient to apply required displacements under cyclic loading)

Environmental Chamber/Fluid Bath Temperature Range: (e.g., Ambient to 40°C or higher, with precise control around 37°C)

Environmental Chamber/Fluid Bath Temperature Accuracy: (e.g., ±1°C or ±0.5°C)

Sample Size Capacity: (Able to accommodate the dimensions of various intervertebral fusion cage designs and sizes)

Power Supply: (e.g., AC 220V or 380V, 50/60 Hz, potentially with a hydraulic power unit if servo-hydraulic)