To address the susceptibility of materials used in components of high-performance machinery, such as aircraft engines, to creep (deformation that...
GMAT Information and Ideas : (Ideas) Questions
To address the susceptibility of materials used in components of high-performance machinery, such as aircraft engines, to creep (deformation that is induced by persistent mechanical stress and that often occurs at elevated temperatures), materials researchers have developed silicon carbide (SiC) fibers for producing aerospace composites. Testing the thermomechanical properties of several commercially available SiC fibers, Ramakrishna T. Bhatt et al. found that in comparison with two polymer-derived SiC fibers, a nitrogen-treated SiC fiber exhibited a lower minimum creep rate, a measure of the rate at which a stress-exposed material deforms at a constant temperature and uniaxial load. The finding suggests that ______
Which choice most logically completes the text?
unlike the two polymer-derived SiC fibers, the nitrogen-treated SiC fiber can substantially inhibit creep, provided that temperatures and loads are consistent.
the two polymer-derived SiC fibers likely hold similar potential for reducing the creep resistance of materials exposed to stress and elevated temperatures, thus prolonging the life span of aerospace machinery.
composites based on the two polymer-derived SiC fibers have chemical properties that may improve the mechanical and thermal stability of aerospace equipment to a greater extent than do composites based on the nitrogen-treated SiC fiber.
aerospace composites containing the nitrogen-treated SiC fiber may have the ability to withstand mechanical stress for a longer period of time than can aerospace composites containing either of the two polymer-derived SiC fibers.
Step 1: Decode and Map the Passage
Part A: Passage Analysis Table
| Text from Passage | Analysis |
|---|---|
| 'To address the susceptibility of materials used in components of high-performance machinery, such as aircraft engines, to creep (deformation that is induced by persistent mechanical stress and that often occurs at elevated temperatures),' |
|
| 'materials researchers have developed silicon carbide (SiC) fibers for producing aerospace composites.' |
|
| 'Testing the thermomechanical properties of several commercially available SiC fibers, Ramakrishna T. Bhatt et al. found that in comparison with two polymer-derived SiC fibers, a nitrogen-treated SiC fiber exhibited a lower minimum creep rate,' |
|
| 'a measure of the rate at which a stress-exposed material deforms at a constant temperature and uniaxial load.' |
|
Main Point: Research shows that nitrogen-treated silicon carbide fibers perform better than polymer-derived ones in resisting creep deformation.
Step 2: Interpret the Question Precisely
This is a fill-in-the-blank question asking us to choose the best logical connector. The answer must create the right relationship between what comes before and after the blank.
Step 3: Prethink the Answer
- The research showed that nitrogen-treated SiC fiber had a lower minimum creep rate than polymer-derived SiC fibers
- Since creep rate measures how fast materials deform under stress and temperature, a lower creep rate means better resistance to deformation
- For aerospace applications where materials face persistent mechanical stress, this superior creep resistance would translate to better performance and longer-lasting components
unlike the two polymer-derived SiC fibers, the nitrogen-treated SiC fiber can substantially inhibit creep, provided that temperatures and loads are consistent.
✗ Incorrect
- Claims nitrogen-treated fiber can substantially inhibit creep with specific conditions
- Adds unnecessary limitations not supported by the research
the two polymer-derived SiC fibers likely hold similar potential for reducing the creep resistance of materials exposed to stress and elevated temperatures, thus prolonging the life span of aerospace machinery.
✗ Incorrect
- Claims polymer-derived fibers hold similar potential for reducing creep resistance
- This contradicts the research finding that showed polymer-derived fibers had higher (worse) creep rates
composites based on the two polymer-derived SiC fibers have chemical properties that may improve the mechanical and thermal stability of aerospace equipment to a greater extent than do composites based on the nitrogen-treated SiC fiber.
✗ Incorrect
- Suggests polymer-derived fibers have better chemical properties and stability
- Directly contradicts the research evidence showing nitrogen-treated fiber had superior creep performance
aerospace composites containing the nitrogen-treated SiC fiber may have the ability to withstand mechanical stress for a longer period of time than can aerospace composites containing either of the two polymer-derived SiC fibers.
✓ Correct
- States that nitrogen-treated fiber composites may have the ability to withstand mechanical stress for a longer period of time
- This directly follows from the lower creep rate finding - less deformation under stress means better long-term durability