STRESS AND STRAIN IN WOOD

Question 1

Branch of science concerned with the behavior of physical bodies when subjected to forces or displacement, and the subsequent effects of the bodies on their environment

Answer 1

Mechanics

Question 2

Wood is considered as an ____________, meaning it has different mechanical properties from its three sections or directions: longitudinal, radial, and tangential.

Answer 2

orthotropic material

Question 3

• applied forces in wood

Answer 3

stress

Question 4

• measure the change/deformation of wood length

Answer 4

strain

Question 5

KINDS OF STRESSES IN WOOD:

Answer 5

a. Compressive Stress
b. Tensile Stress
c. Shear Stress

Question 6

• A type of stress that develops when a material is subjected to an external force that tends to squeeze or shorten the wood.

Answer 6

Compressive Stress

Question 7

• reduces the length/dimension of wood
• shorten the wood
• inward

Answer 7

Compressive Stress

Question 8

• Exerted on a wood if the force tends to increase or to expand the dimension or volume of the wood.

Answer 8

Tensile Stress

Question 9

• increase/expand volume of wood
• outward

Answer 9

Tensile Stress

Question 10

• Relevant in situations where forces act parallel to the grain, causing adjacent layers of wood fibers to slide or deform.

Answer 10

Shear Stress

Question 11

• Result from forces that tends to cause portions of a wood to move or slide in parallel but opposite direction.

Answer 11

Shear Stress

Question 12

• move or slide parallel to the grain

Answer 12

Shear Stress

Question 13

• Force acts perpendicular to area of contact

Answer 13

Normal Stress

Question 14

• Referred to as the change in length per unit of length in the direction of stress.

Answer 14

STRAIN IN WOOD

Question 15

• Measure of the deformation or
  change in the shape of the
  material that results from the
  applied force.

Answer 15

STRAIN IN WOOD

Question 16

Stress is usually expressed in ____________ or in pascals (Newton per square meter)

Answer 16

pounds per square inch (psi)

Question 17

• is referred to as the change in length per unit of length in the direction of stress.

Answer 17

Strain

Question 18

• Resistance of the wood specimen from being deformed when stress is applied, and a longer line of ______ means it has a greater resistance to deformity.

Answer 18

MODULUS OF ELASTICITY (MOE)

Question 19

• ability of wood to recover to the original state/form

Answer 19

MODULUS OF ELASTICITY (MOE)

Question 20

Stress and Strain curve for a wood specimen tested ________

Answer 20

parallel-to-grain

Question 21

DEFORMATION IN WOOD:

Answer 21

a. Elastic Deformation
b. Total Deformation

Question 22

• When there is a sudden change in the shape of wood when load/stress is applied but the change is recoverable when stress is removed
• temporary

Answer 22

Elastic Deformation

Question 23

• It is the line beyond the stress at
  proportional limit , where the change in size or shape of the wood when applied with stress is no longer recoverable.

Answer 23

Total Deformation

Question 24

• the wood specimen applied with load/stress parallel to grain has the capacity to withstand the load until it reaches its breaking point, the amount or intensity of the load that caused the wood specimen to break or fail

Answer 24

MODULUS OF RUPTURE