Dynamic Strain Rate Modeling for Multi Ply Boxboard under Rapid Compression
Dynamic strain rate modeling predicts multi-ply boxboard Z-direction compression and interlayer shear collapse during high-speed converting and package drops.
Z-Direction Compression
Board Resistance
Mechanical stress applied perpendicular to the plane of a paperboard sheet measures internal bond strength through z-direction compression. Containerboard grades must withstand stacking loads without failing internally when heavy goods sit inside corrugated boxes on pallets. Paper mills evaluate this property by applying vertical force until the fibrous matrix separates between internal plies.
Corrugated converters rely on these measurements to prevent delamination during high-speed printing nip pressure or automated case erection. Low internal bond values cause flute tips to tear away from liners during converting operations.
Ply Separation
Interlaminar failure occurs when vertical forces exceed internal bonding strength within multi-layer paperboard structures. Recycled linerboard grades containing short secondary fibres exhibit higher susceptibility to internal splitting under sustained warehouse loads. Papermakers control this phenomenon by refining chemical pulp stock and applying specific sizing agents during wet end formation.
Humidity fluctuations weaken hydrogen bonds between adjacent cellulose layers, reducing the total load a box blank can sustain before structural collapse. Converting machinery introduces localized shear stress that accelerates internal delamination if board stiffness exceeds internal cohesion limits.
Stress Tolerance
Structural integrity depends upon maintaining adequate internal adhesion throughout deep thermal drying stages on the paper machine. Heavyweight packaging grades require uniform moisture profiles across the web to prevent weak zones that fail prematurely during palletization. Quality control laboratories test sample coupons by crushing standardized board specimens between precision steel platens until internal rupture registers on the load cell.
Mill operators adjust pressing loads and dryer temperatures to optimize fibre orientation and interweaving density. Proper calibration ensures that finished corrugated containers endure long-term dynamic warehouse stacking without buckling internally.
Predicting Dynamic Z Direction Fiber Compression Rates under Heated High Speed Embossing Platens
Predicting dynamic Z-direction fiber compression requires balancing dwell time, thermal diffusivity, and lignin glass transition to maximize permanent set.