chapter 4 (1-15)

11.Explain the difference between an elastic and a plastic material.

An elastic material is a material that if fully recoverable from deformation after the load is removed due to the elasticity of the material. A plastic material is a material that does not recover from its deformation after the removal of the load. (Can be called an inelastic or plastic, material). (pg 96)

3. What is the difference between a ductile material and a brittle material?

Ductile material is a material that produces large deformations before failure, its ultimate strain is greater than 0.5% examples are metals are ductile Brittle material is a material that DOES NOT deform much before failure, its ultimate strain is less than or equal too 0.5% example is brick, stone , concrete (pg 94)

12. Is low-carbon steel an elastic or a plastic material?

Low-carbon steel is an elastic-plastic material because it is elastic up to the yield point or a certain stress value but plastic thereafter. (pg 96)

8. List the following materials (aluminum, concrete, steel, and wood) in terms of their ductility beginning with the most ductile and ending with the least ductile

Most ductile- Steel Aluminum Wood Concrete. (pg 94)

4. What is the relationship between a material's brittleness and its tensile strength?

One of the characteristics of brittle material is that they are stronger in compression than in tension. (pg 94)

13.In the stress-strain diagrams of materials, which axis (X-axis or Y-axis) is typically used for stress and which for strain?

Stress typically goes on the Y-axis and Strain typically goes on the X-axis. (pg 97)

1. What is the shape and dimensions of the specimen typically used for determining the compressive strength of concrete?

The shape is a cylinder of concrete and and it is 6 inches in diameter by 12 inches tall that they do the test on to determine the compressive strength of the concrete (pg 92)

14. Does the slope of the stress-strain diagram relate to any property of the material? Explain

The slope of a material's stress-strain diagram gives the magnitude of the modulus of elasticity of the material, E. The greater the slope, the greater the value of E which means the material has a greater stiffness.(pg 97)

15.What is the unit of measure for modulus of elasticity in U.S. System of units? In SI System of units?.

The unit of the modulus of is psi or ksi in the U.S. system and a pascal in the SI sytem.(pg 97)

9. Explain what yielding of a material means.

The yielding, or yield strength, is the maximum strength a material experiences before excessive deformation. (pg 95)

2.If a concrete test cylinder measuring 6 in. x 12 in. breaks when the load on it reaches 169.5 k, what is the compressive strength of concrete? Express the strength in psi.

compressive strength = load of failure/ area of cylinder= # ksi then convert to psi 169.5/28.27= 6 ksi 6,000 psi (pg 92)

10. What is the yield stress of grade 60 reinforcing steel? Of A-36 structural steel?.

its on page 96 at the top. teel used as reinforcing bars in concrete is called grade 40 or grade 60 steel depending on whether its yield stress is 40 ksi or 60 ksi

6.What is the unit of measure for strain?

strain has no units because it is the ratio of two lengths. therefore, it is a number with no units of measurement.