Characterizing Anisotropic Material Behaviour

Planar Biaxial TestBench instrument from Bose is a soft tissue characterization equipment with superior performance and control. It is specifically designed for monitoring the non-linear stress-strain relationships and mechanical anisotropy of a wide variety of samples including tissue such as heart valve leaflets, pericardium and skin, and engineered devices such as wound repair meshes and wearable sensors.

This article describes in detail about the versatile Planar Biaxial TestBench instrument and its accessories designed to suit various research needs.

Characteristics of Planar Biaxial TestBench Instrument

The following are the major characteristics of the Planar Biaxial TestBench instrument:

• Controllability - Experimental parameters such as displacement control, strain control, synchronized or independent control of actuators, and load control are easily regulated to characterize different materials in a precise manner. Figure 1 shows the graph indicating load vs displacement of specific material.

Figure 1. Graph indicating load vs displacement of specific material

• Non-contact strain measurements - Two-dimensional strain measurements such as primary, secondary and transverse strains are carried out in a physiologically-relevant environment. The data output for modeling is correlated using a strain marker.
• High performance - The instrument enables the users to select parameters such as wave shape (loading profile), frequency, displacement and force without compromising accuracy. Figure 2 shows the graph illustrating the force domain against time domain of specific material.

Figure 2. Graph illustrating the force domain against time domain of specific material.

• Versatility - The instrument performs a number of tests in the field of material engineering, mechanical and biomedical, which include performing fatigue testing on sensors and medical devices for a number of cycles, monitoring viscoelasticity, nonlinear stress-strain relationships and anisotropy, comparing mechanical properties of biomaterials to biological tissues and generating constitutive models to understand material behavior.

Key Features

The main features of the Planar Biaxial TestBench instrument are:

• Bose friction-free moving- magnet linear motor offers superior performance for a wide range of force and displacement.
• Hook or clamp tensile grips as show in Figure 3
• Extended stroke and torsion actuators
• Sterile BioDynamic^® chamber as shown in Figure 4
• Heated saline bath as shown in Figure 5 maintained from ambient to 45°C
• Digital video extensometer with standard and high resolution options as shown in Figure 6
• WinTest^® software add-on packages with custom waveform importation and dynamic mechanical analysis (DMA). Accelerometers can also be used for dynamic load compensation.

Figure 3. Schematic of hook and tensile grips

Figure 4. Schematic of BioDynamic^® chamber

Figure 5. Schematic of heated saline bath

Figure 6. Schematic of digital video extensometer

Specifications

The specifications of the Planar Biaxial TestBench instrument are given below:

• Frequency: 0-100Hz
• Displacement: 25mm
• Static force: ± 140N
• Dynamic force: ± 200N (± 400 N option available)
• Baseplate dimensions: 914 x 914 x 50mm
• Calibrated sensor accuracy - Force calibrated to ASTM E4 and displacement calibrated to ASTM E2309, Class A displacement measurement error

Conclusion

Bose test instruments are suitable for multi-sample and multi-axis testing, durability and high-cycle fatigue testing, monotonic tensile and compression testing, and creep and stress-relaxation testing.

The instruments comes along with calibration and data control, protocol development assistance, free online training sessions, and unlimited phone technical support in addition to 10-year motor warranty.

This information has been sourced, reviewed and adapted from materials provided by TA Instruments.

For more information on this source, please visit TA Instruments.