Microscopic localized necking and knife-edge indentation from biaxial extensometers introduce uncompensated strain measurement imbalances, severely distorting the computed width-to-length strain slope.
Deploy a high-resolution, synchronous axial-transverse extensometer or a non-contact video extensometer array paired with parallel-action pneumatic side grips.
Ensure the specimen edges are polished completely free of blanking burrs; even minor edge roughness skews the transverse width extensometer reading.
Ensure the specimen edges are polished completely free of blanking burrs; even minor edge roughness skews the transverse width extensometer reading.
The r-value is a critical index of a sheet metal’s drawability; a high r-value indicates a material that resists thinning under deep-drawing stress states.
For maximum data fidelity, utilize a non-contact video extensometer system to capture width reduction across multiple parallel lines simultaneously.
Extracting width data from post-test manual micrometer measurements instead of continuous real-time extensometry, which ignores elastic springback artifacts.
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
Knife-edge slippage of the transverse strain sensor or out-of-plane specimen bowing, yielding highly volatile or negative r-value data points.
Root Cause Analysis
Inadequate jaw clamping pressure causing microscopic specimen slippage, or burrs along the specimen edges that corrupt transverse tracking.
Hardware Specific Solutions
High-stiffness electromechanical universal testing machine equipped with a multi-channel synchronous strain processing module and dual-axis extensometry.