Specimen barrelling and surface friction against compression plates distort pure uniaxial compressive stress states.
Incorporate highly polished, lubricated solid platens or specialized self-aligning spherical seat compression assemblies.
Apply a thin, uniform layer of silicone oil or petroleum jelly to platens to minimize interfacial friction coefficients.
Apply a thin, uniform layer of silicone oil or petroleum jelly to platens to minimize interfacial friction coefficients.
Minimizing friction constraints avoids invalid barrelling profiles and ensures pure axial deformation metrics.
Always precondition specimens with three structural load/unload cycles to stable baseline responses prior to official logging.
Using unpolished or dirty platens that restrict natural material expansion during extreme down-strokes.
Typical testing system controllers rely on 24-bit resolution. Under high-accuracy flexural analysis, this creates a data phenomenon called **”stair-stepping”** or quantization error. When trying to track minor micro-deflection in rigid polymers, 24-bit electronic circuits suffer from resolution limits, dropping critical transition points during initial load curves.
Newton Characterization™ architecture utilizes a 32-bit analog-to-digital processor converter. This increases measurement fidelity by a factor of 256x, outputting 4.29 billion discrete signal thresholds. Electrical chatter is actively muted under a dedicated 100,000:1 Signal-to-Noise Ratio (SNR).
Comparing standard 24-bit quantization with Newton™ 32-bit resolution
Observe the stepped resolution blocks in the legacy 24-bit curve (Red) versus the absolute **analog-smooth response curve** captured by Newton™ 32-bit architectures (Green). This fidelity is what prevents mechanical data variance during modulus evaluation.
Expert Engineering Commentary
Core Problem Identification
Slippage or irregular specimen extrusion leading to asymmetric stress tracking and artificial stiffness inflation.
Root Cause Analysis
Frictional binding at the platen interfaces causing geometric bulging (barrelling) instead of uniform radial expansion.
Hardware Specific Solutions
Hardened, mirror-polished compression platens (Ra < 0.2 microns) with integrated debris channels and a self-aligning sub-press.