Material Failures and Selection in Engineering

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Why is life cycle cost evaluation important when selecting materials for a structure?

It is only relevant for structures made of a single material type.

It solely focuses on the initial costs, ensuring budget adherence.

It is mandated by international building codes for all construction projects.

It considers the maintenance cost and lifespan, providing a comprehensive economic analysis. (correct)

A pavement is experiencing excessive surface roughness, even though stress levels are within the material's capabilities. What type of failure is this considered?

Material fatigue

Functional failure (correct)

Catastrophic failure

Structural failure

How does temperature change typically affect the mechanical behavior of viscoelastic materials like plastics and asphalt compared to materials like metals and concrete?

Viscoelastic materials are more susceptible to changes in temperature compared to metals and concrete. (correct)

Viscoelastic materials are less affected by temperature changes compared to metals and concrete.

Temperature changes have no effect on viscoelastic materials.

Temperature changes only affect the density of viscoelastic materials.

Why is the density/unit weight of construction materials an important consideration in structural design?

It significantly contributes to the total design stress due to the dead weight of the materials. (D) Signup and view all the answers

A bridge designer is choosing between steel and concrete for a new bridge. Which material property should be carefully considered to account for seasonal temperature variations?

Thermal expansion (C) Signup and view all the answers

A structural engineer notices that a newly constructed building vibrates excessively in high winds, despite all stress calculations being within acceptable limits. What type of material failure is likely occurring?

Functional failure (B) Signup and view all the answers

An engineer is designing a new road surface. The material's mechanical properties indicate high load-bearing capacity, but the surface becomes dangerously slippery when wet. What key consideration regarding material selection has been overlooked?

Surface Characteristics (C) Signup and view all the answers

When selecting materials for a building in an area with extreme temperature variations, what combination of properties should an engineer prioritize to ensure long-term structural integrity?

Low thermal expansion and high mechanical strength (C) Signup and view all the answers

A structure is composed of two materials with different coefficients of thermal expansion. What is the most likely outcome when the temperature changes?

The material with the lesser coefficient will restrict the straining of the other material, potentially causing stress. (D) Signup and view all the answers

What is the primary mechanism by which crystalline materials, such as metals and ceramics, deteriorate?

Dissolution or formation of nonmetallic scale or film through corrosion. (B) Signup and view all the answers

Which factor is most important to consider when selecting materials for a structure exposed to a corrosive environment?

The cost of preventing environmental degradation and how the material will react with the environment. (B) Signup and view all the answers

A civil engineer is designing a bridge in a cold climate. Which material property is most important to consider to prevent fractures?

A coefficient of thermal expansion similar to other bound materials. (B) Signup and view all the answers

Why is abrasion and wear resistance typically of less importance in civil engineering compared to mechanical engineering?

Civil engineering structures are generally static, experiencing less friction than parts in machinery. (A) Signup and view all the answers

Asphalt is a polymer commonly used in road construction. What is the primary mechanism by which asphalt deteriorates?

Degradation from solvents and UV radiation. (B) Signup and view all the answers

A newly constructed concrete bridge exhibits cracking after the first winter. Assuming proper construction techniques were followed, what is the most likely cause of these cracks?

Differential thermal expansion between the concrete and steel reinforcement. (A) Signup and view all the answers

Which of the following scenarios would require the greatest consideration of a material's abrasion resistance?

Choosing a material for a heavily trafficked airport runway. (D) Signup and view all the answers

Why is abrasion and wear resistance particularly important for aggregates used in pavement construction?

To provide adequate skid resistance by resisting the polishing action of vehicle tires. (B) Signup and view all the answers

How does the surface texture of aggregate particles impact the workability and stability of concrete mixtures?

Smooth textures in portland cement concrete improve workability, while rough textures in asphalt concrete enhance stability. (A) Signup and view all the answers

What is a key consideration regarding high-strength concrete, or steel, usage in different cities for skyscraper construction?

Regional preferences based on engineer familiarity, workforce training, and available equipment significantly influence material selection. (B) Signup and view all the answers

What production considerations might prevent the selection of an otherwise suitable material for a civil engineering project?

Limited availability of the material or fabrication challenges to meet required specifications. (C) Signup and view all the answers

Which surface characteristic of materials is critical for ensuring safety and preventing accidents on road surfaces?

Surface texture, which provides adequate friction resistance and prevents skidding. (B) Signup and view all the answers

In the context of material selection for civil engineering, what encompasses 'construction considerations'?

Factors related to the ability to fabricate and erect a structure on-site, including workforce training. (A) Signup and view all the answers

Why might a civil engineering project prioritize using aggregates with a specific surface texture?

To enhance specific properties in the final application, such as workability or stability. (C) Signup and view all the answers

Beyond material properties, what other factor significantly affects material selection in civil engineering projects?

Production and construction considerations, including workforce skills and equipment. (D) Signup and view all the answers

What is the primary reason for materials engineers to focus on quality control during construction?

To ensure structures are safe, efficient, sustainable, and economically viable. (D) Signup and view all the answers

How does the selection of steel versus reinforced concrete affect construction projects?

Steel structures are typically faster to assemble due to off-site fabrication. (C) Signup and view all the answers

How has the ASCE Code of Ethics evolved in recent decades regarding material selection?

It now includes sustainable development as a key consideration. (C) Signup and view all the answers

What role does transportation play in the economics of construction material selection?

It influences material availability and significantly adds to the final cost. (A) Signup and view all the answers

What should guide engineers' decisions when selecting materials for a project?

Balancing project requirements, client needs, and environmental considerations. (A) Signup and view all the answers

How do precast concrete units address some of the challenges associated with traditional reinforced concrete construction?

By reducing on-site construction time and complexity. (C) Signup and view all the answers

What is a lasting concern regarding material selection?

All materials deteriorate over time and with use. (B) Signup and view all the answers

Which factor has grown in importance when considering material selection?

Sustainability. (A) Signup and view all the answers

Deterioration

The decline in a structure's condition affecting cost and life.

Life Cycle Cost

Total cost of a material over its entire life, including maintenance.