Join 60,000+ competitive exam aspirants
or with email
Your Cart
Subtotal₹0
Total₹0
Examoogle • User • info@examoogle.com • EE-2024-8821
Chapter 1 of 12 • Page 1 of 248🔒 Protected PDF • Watermarked
Join 60,000+ competitive exam aspirants
In plywood, three or more veneers in odd numbers are placed one above the other with the direction of grains of successive layers at ________ to each other.
60°
30°
45°
90°
90°
Plywood is an engineered wood product manufactured by bonding thin layers of wood veneers together. The grain direction of successive layers is placed at 90° to each other to ensure structural uniformity and enhanced mechanical properties.
IS 303:1989
Plywood is an engineered wood product manufactured by bonding thin layers of wood veneers together. The grain direction of successive layers is placed at 90° to each other to ensure structural uniformity and enhanced mechanical properties.
Eeff=t1∑i=1nEiti — effective elastic modulus calculation considering layered orthotropic properties
The primary objective of cross-banding is to counteract the natural anisotropic behavior of wood. Since wood shrinks and swells significantly more in the tangential direction than in the longitudinal direction due to moisture changes, orienting grains at 90° ensures that expansion in one layer is constrained by the longitudinal stiffness of the adjacent layer, thereby minimizing warping and splitting.
Veneers are typically arranged in odd numbers (3,5,7,…) to maintain a balanced construction across the central axis.
The central layer is known as the core, while outer layers are called faces.
Cross-banding reduces the tendency of the plywood to warp or twist under varying humidity conditions.
The shear strength of plywood is significantly higher compared to solid timber of similar thickness.
High strength-to-weight ratio
Enhanced dimensional stability
Resistance to splitting
Large surface area availability compared to sawn timber
Susceptibility to moisture at edges if not sealed
Presence of adhesives (resins) can pose environmental concerns if formaldehyde-based
Edges require finishing or banding
Furniture manufacturing
Structural panels in construction (roofing, flooring)
Formwork for concrete casting
Interior paneling and cabinetry
The odd number of veneers ensures the grain orientation of the top and bottom face veneers is in the same direction, which balances the internal stresses.
Option A (60°), B (30°), and C (45°) would result in uneven stress distribution and significant warping due to anisotropic moisture movement.
D is correct — In plywood, successive veneers are arranged at 90° to each other to provide balanced strength and dimensional stability.
Always remember that wood strength is highest parallel to the grain; by layering at 90°, plywood effectively distributes this high strength in two perpendicular directions.
Get instant step-by-step AI explanations, full shift Previous Year Papers (SSC GD, RRB, SSC JE), and regional rank analysis on the official Examoogle App.
Free Download • 100K+ Aspirants