Parasitic bending and peeling moments generated by thick bonding plates distort pure planar shear states inside the core.
Utilize , precision-ground steel loading plates paired with self-aligning knife-edge or universal joint frame adapters.
Always sandblast and solvent-wipe the steel loading plates to bare metal immediately before applying epoxy to prevent premature bond line peeling.
Always sandblast and solvent-wipe the steel loading plates to bare metal immediately before applying epoxy to prevent premature bond line peeling.
Proper load alignment completely eliminates external bending moments, forcing pure, unadulterated planar shear stress.
Ensure the line of action of the applied force passes directly through the diagonally opposite corners of the sandwich core.
Using an elastic epoxy that is too flexible, which introduces secondary compliance errors into the core shear modulus calculation.
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
Adhesive bond line failure at the plate interface before achieving true ultimate shear failure within the core.
Root Cause Analysis
Inadequate surface preparation or improper selection of the high-strength structural adhesive used for plate bonding.
Hardware Specific Solutions
Heavy-duty dual-plate shear testing fixture with heat-treat hardened alignment tracking pins and low-friction universal joints.