Please keep at least one language enabled. || కనీసం ఒక భాషను ఎంచుకోండి.
Question 1
ప్రశ్న 1
Which feature most clearly distinguishes thick-cylinder stress analysis from the elementary thin-cylinder approximation?
Explanation:
A thick cylinder has sufficient wall thickness for the stress variation through the wall to become important. Radial stress cannot generally be neglected because it varies between the prescribed pressures at the inner and outer surfaces. Circumferential or hoop stress also changes with radial position rather than remaining uniform. Lamé's equations describe these radial variations under axisymmetric loading. Therefore Option A correctly distinguishes thick-cylinder analysis from thin-shell theory.
వివరణ:
Question 2
ప్రశ్న 2
Using tensile normal stress as positive, which pair represents Lamé's equations for radial and circumferential stresses in a thick cylinder under axisymmetric pressure loading?
Explanation:
Lamé's solution for an axisymmetric thick cylinder contains a constant term and an inverse-square radial term. With tensile stress taken as positive, radial stress is written as σr = A - B/r². Circumferential stress is σθ = A + B/r². The constants A and B are determined from the pressure boundary conditions at the inner and outer surfaces. Therefore Option A is correct.
వివరణ:
Question 3
ప్రశ్న 3
A thick cylinder has inner radius a, outer radius b, internal pressure pi and external pressure po. With tensile stress taken as positive, which radial-stress boundary conditions are correct?
Explanation:
Pressure acts normally inward on a material surface and therefore produces compressive normal stress. Under a tension-positive sign convention, a compressive radial stress is negative. At the bore surface the radial stress must therefore equal -pi. At the outer surface the radial stress must equal -po. Hence Option B gives the correct Lamé boundary conditions.
వివరణ:
Question 4
ప్రశ్న 4
For a thick cylinder with inner radius a, outer radius b, internal pressure pi and external pressure po, which expressions correctly determine the Lamé constants A and B?
Explanation:
The constants are obtained by imposing σr(a) = -pi and σr(b) = -po on σr = A - B/r². Solving the two simultaneous equations gives A = (pi a² - po b²)/(b² - a²). The inverse-square constant is B = (pi - po)a²b²/(b² - a²). The dimensions of A are stress, while B has dimensions of stress multiplied by length squared. Therefore Option A is correct.
వివరణ:
Question 5
ప్రశ్న 5
A thick cylinder is subjected to internal pressure only, with zero external pressure. Where does the maximum tensile circumferential stress occur?
Explanation:
For internal pressure only, the Lamé constant B is positive. Circumferential stress is σθ = A + B/r². Since 1/r² decreases as the radial coordinate increases, σθ decreases from the bore toward the outer surface. The largest tensile circumferential stress therefore occurs at the smallest radius, namely the inner surface. Hence Option C is correct.
వివరణ:
Question 6
ప్రశ్న 6
A thick cylinder has inner radius 100 mm, outer radius 150 mm and internal pressure 12 MPa, with zero external pressure. What are the radial and circumferential stresses at the inner surface?
Explanation:
For a = 100 mm, b = 150 mm and pi = 12 MPa, the Lamé constants are A = 9.6 MPa and B = 216000 MPa·mm². At the inner radius, the radial-stress boundary condition requires σr(a) = -12 MPa. The circumferential stress is obtained from σθ = A + B/r². At r = 100 mm, this gives σθ = 9.6 + 216000/100² = 31.2 MPa. Therefore Option A is correct.
వివరణ:
Question 7
ప్రశ్న 7
For the same cylinder with a = 100 mm, b = 150 mm and pi = 12 MPa, what are the radial and circumferential stresses at the outer surface?
Explanation:
The outer surface is not subjected to external pressure, so its radial stress must be zero. The Lamé constants are A = 9.6 MPa and B = 216000 MPa·mm². At r = 150 mm, the inverse-square term is B/r² = 216000/150² = 9.6 MPa. Thus σθ = 9.6 + 9.6 = 19.2 MPa while σr = 9.6 - 9.6 = 0. Therefore Option B is correct.
వివరణ:
Question 8
ప్రశ్న 8
For the thick cylinder with a = 100 mm, b = 150 mm and pi = 12 MPa, what are the stresses at radius r = 125 mm approximately?
Explanation:
For this cylinder, A = 9.6 MPa and B = 216000 MPa·mm². At r = 125 mm, B/r² = 216000/15625 = 13.824 MPa. Hence σr = 9.6 - 13.824 = -4.224 MPa. The hoop stress is σθ = 9.6 + 13.824 = 23.424 MPa. Therefore Option A is correct.
వివరణ:
Question 9
ప్రశ్న 9
For a thick cylinder with a = 100 mm, b = 150 mm and internal pressure 12 MPa only, what are the Lamé constants A and B?
Explanation:
For zero external pressure, A = pi a²/(b² - a²). Substitution gives A = 12 × 100²/(150² - 100²) = 9.6 MPa. The second Lamé constant is B = pi a²b²/(b² - a²). Substitution gives B = 216000 MPa·mm². Therefore Option A is correct.
వివరణ:
Question 10
ప్రశ్న 10
A thick cylinder has inner radius 100 mm, outer radius 150 mm, internal pressure 20 MPa and external pressure 5 MPa. What are the circumferential stresses at the inner and outer surfaces?
Explanation:
For the stated pressures, A = (20 × 100² - 5 × 150²)/(150² - 100²) = 7 MPa. The second constant is B = (20 - 5)100²150²/(150² - 100²) = 270000 MPa·mm². At the bore, σθ = 7 + 270000/100² = 34 MPa. At the outside, σθ = 7 + 270000/150² = 19 MPa. Therefore Option A is correct.
వివరణ:
Question 11
ప్రశ్న 11
For the cylinder with a = 100 mm, b = 150 mm, pi = 20 MPa and po = 5 MPa, what are the radial and circumferential stresses at r = 125 mm?
Explanation:
For this loading, A = 7 MPa and B = 270000 MPa·mm². At r = 125 mm, B/r² = 270000/15625 = 17.28 MPa. Therefore σr = 7 - 17.28 = -10.28 MPa. The circumferential stress is σθ = 7 + 17.28 = 24.28 MPa. Hence Option A is correct.
వివరణ:
Question 12
ప్రశ్న 12
A thick cylinder has inner radius 80 mm and outer radius 120 mm and is subjected only to an external pressure of 10 MPa. Which set of surface stresses is correct?
Explanation:
For external pressure only, the inner bore is pressure-free, so σr(a) = 0. The outer boundary is subjected to 10 MPa pressure, so σr(b) = -10 MPa. Applying Lamé's equations gives A = -18 MPa and B = -115200 MPa·mm². The hoop stresses are consequently -36 MPa at the inner surface and -26 MPa at the outer surface. Therefore Option A is correct.
వివరణ:
Question 13
ప్రశ్న 13
A thick cylinder has inner radius 100 mm and outer radius 150 mm and is subjected only to internal pressure. If the allowable maximum hoop stress at the bore is 100 MPa, what is the maximum permissible internal pressure according to Lamé's equation?
Explanation:
For internal pressure only, the maximum hoop stress occurs at the bore. Its value is σθ(a) = pi(a² + b²)/(b² - a²). Solving this expression for pi gives pi = σallow(b² - a²)/(a² + b²). Substitution gives pi = 100 × 12500/32500 = approximately 38.46 MPa. Therefore Option C is correct.
వివరణ:
Question 14
ప్రశ్న 14
A thick cylinder has a fixed inner radius of 100 mm and carries an internal pressure of 20 MPa with zero external pressure. If the maximum allowable hoop stress at the bore is 80 MPa, what minimum outer radius is required according to Lamé's equation?
Explanation:
For internal pressure only, σθ(a) = pi(a² + b²)/(b² - a²). Setting σθ(a) = 80 MPa and pi = 20 MPa gives 4 = (a² + b²)/(b² - a²). Rearranging this equation gives 3b² = 5a². With a = 100 mm, the required outer radius is b = 100√(5/3) ≈ 129.1 mm. Therefore Option C is correct.
వివరణ:
Question 15
ప్రశ్న 15
For fixed cylinder geometry and fixed internal pressure pi, the external pressure po is increased from zero while remaining less than pi. Which statement is correct according to Lamé's equations?
Explanation:
The Lamé constant B is proportional to the pressure difference pi - po. Increasing po while holding pi and the geometry fixed therefore decreases B. Direct substitution into the surface hoop-stress expressions also shows that both inner and outer circumferential stresses decrease as po increases. The radial boundary stresses simultaneously change to -pi at the bore and -po at the outside. Therefore Option A is correct.
వివరణ:
Question 16
ప్రశ్న 16
A thick cylinder is subjected to equal internal and external pressures p. What stress state is predicted by Lamé's equations in the radial-circumferential plane?
Explanation:
If pi = po = p, the Lamé constant B becomes zero because it is proportional to pi - po. The constant A becomes -p. The radial equation therefore reduces to σr = -p throughout the wall. The circumferential equation likewise gives σθ = -p everywhere. Thus Option A is correct.
వివరణ:
Question 17
ప్రశ్న 17
According to Lamé's equations, which quantity is independent of radius throughout the wall of a thick cylinder?
Explanation:
Lamé's equations are σr = A - B/r² and σθ = A + B/r². Adding the two equations gives σr + σθ = 2A. The inverse-square terms cancel exactly. Since A is constant for a specified cylinder and pressure loading, this sum is independent of radius. Hence Option B is correct.
వివరణ:
Question 18
ప్రశ్న 18
How does the difference between circumferential and radial stress vary with radius according to Lamé's equations?
Explanation:
Subtracting σr = A - B/r² from σθ = A + B/r² eliminates the constant A. The result is σθ - σr = 2B/r². Therefore the stress difference varies inversely with the square of the radial coordinate whenever B is non-zero. For internal-pressure-dominant loading, this difference is largest near the bore. Hence Option A is correct.
వివరణ:
Question 19
ప్రశ్న 19
A thick cylinder has a = 100 mm, b = 200 mm, internal pressure 10 MPa and external pressure 5 MPa. At what radius does the circumferential stress change from tensile to compressive?
Explanation:
For this cylinder, A = (10 × 100² - 5 × 200²)/(200² - 100²) = -3.333 MPa. The second constant is B = (10 - 5)100²200²/(200² - 100²) = approximately 66666.7 MPa·mm². Hoop stress changes sign where A + B/r² = 0. Thus r² = -B/A = 20000 mm², giving r ≈ 141.4 mm. Therefore Option B is correct.
వివరణ:
Question 20
ప్రశ్న 20
A closed-end thick cylinder with inner radius 100 mm and outer radius 150 mm is subjected only to an internal pressure of 12 MPa. Assuming the pressure acts on the closed bore area and is resisted uniformly by the annular metal area, what longitudinal stress is produced away from end disturbances?
Explanation:
The axial pressure force acting on the closed end is piπa². The resisting annular metal area is π(b² - a²). Therefore the uniform longitudinal stress is pi a²/(b² - a²). Substitution gives 12 × 100²/(150² - 100²) = 9.6 MPa tension. For this internal-pressure-only case, this value is also equal to the Lamé constant A, so Option B is correct.
వివరణ:
Question 21
ప్రశ్న 21
A thick cylinder has inner radius 50 mm, outer radius 100 mm and internal pressure 8 MPa, with zero external pressure. What are the radial and circumferential stresses at the inner surface?
Explanation:
For internal pressure only, the radial stress at the bore must equal -8 MPa. The inner-surface hoop stress is σθ(a) = pi(a² + b²)/(b² - a²). Here this becomes 8(50² + 100²)/(100² - 50²). The calculated circumferential stress is approximately 13.33 MPa tension. Therefore Option A is correct.
వివరణ:
Question 22
ప్రశ్న 22
For the cylinder in the previous question, considering only the radial and circumferential stresses at the inner surface, what is the maximum in-plane shear-stress magnitude there?
Explanation:
At the bore, the radial and circumferential stresses are -8 MPa and approximately +13.33 MPa respectively. Under axisymmetric pressure loading there is no r-θ shear stress, so these normal stresses are principal stresses in that plane. The maximum in-plane shear magnitude is one-half of the difference between the two principal stresses. Thus τmax = [13.33 - (-8)]/2 ≈ 10.67 MPa. Therefore Option C is correct.
వివరణ:
Question 23
ప్రశ్న 23
Consider the following statements about Lamé stress distributions in a thick cylinder:
1. Radial stress at a pressure boundary equals the negative of the applied pressure when tensile stress is positive.
2. Under internal pressure only, tensile hoop stress is normally maximum at the inner surface.
3. The quantity σr + σθ is constant through the wall according to Lamé's equations.
4. Under internal pressure only with zero external pressure, radial stress is tensile at the bore.
Which statements are correct?
1. Radial stress at a pressure boundary equals the negative of the applied pressure when tensile stress is positive.
2. Under internal pressure only, tensile hoop stress is normally maximum at the inner surface.
3. The quantity σr + σθ is constant through the wall according to Lamé's equations.
4. Under internal pressure only with zero external pressure, radial stress is tensile at the bore.
Which statements are correct?
Explanation:
Statement 1 is correct because pressure produces compressive radial normal stress at the boundary. Statement 2 is correct because the positive B/r² term in the hoop stress is largest at the smallest radius under internal-pressure-only loading. Statement 3 is correct because σr + σθ = 2A throughout the wall. Statement 4 is incorrect because the bore radial stress equals -pi and is therefore compressive. Hence Statements 1, 2 and 3 are correct and Option B is the unique answer.
వివరణ:
Question 24
ప్రశ్న 24
Match each thick-cylinder quantity with its correct Lamé relationship or boundary condition:
1. Radial stress
2. Circumferential stress
3. Inner radial boundary condition
4. Outer radial boundary condition
P. A + B/r²
Q. -po
R. A - B/r²
S. -pi
Which matching is correct?
1. Radial stress
2. Circumferential stress
3. Inner radial boundary condition
4. Outer radial boundary condition
P. A + B/r²
Q. -po
R. A - B/r²
S. -pi
Which matching is correct?
Explanation:
Lamé radial stress is σr = A - B/r², so item 1 matches R. Circumferential stress is σθ = A + B/r², so item 2 matches P. At the inner radius, tensile-positive radial stress equals -pi, making item 3 match S. At the outer radius, radial stress equals -po, so item 4 matches Q. Therefore Option A gives the correct complete matching.
వివరణ:
Question 25
ప్రశ్న 25
A thick cylinder has inner radius 100 mm and outer radius 200 mm and is subjected only to internal pressure. If the measured circumferential stress at the outer surface is 8 MPa, what are the internal pressure and the circumferential stress at the bore?
Explanation:
For internal pressure only, the outer-surface hoop stress is σθ(b) = 2pi a²/(b² - a²). With a = 100 mm and b = 200 mm, this becomes σθ(b) = (2/3)pi. Setting the measured outer hoop stress equal to 8 MPa gives pi = 12 MPa. The bore hoop stress is then pi(a² + b²)/(b² - a²) = 12 × 50000/30000 = 20 MPa. Therefore Option B is correct.
వివరణ:
Answer Key సమాధానాల పట్టిక
-
Question 1 ప్రశ్న 1Answer: A. Radial stress and circumferential stress can vary significantly through the wall thickness and must be determined as functions of radius. సమాధానం: A.
-
Question 2 ప్రశ్న 2Answer: A. σr = A - B/r² and σθ = A + B/r² సమాధానం: A.
-
Question 3 ప్రశ్న 3Answer: B. σr(a) = -pi and σr(b) = -po సమాధానం: B.
-
Question 4 ప్రశ్న 4Answer: A. A = (pi a² - po b²)/(b² - a²), B = (pi - po)a²b²/(b² - a²) సమాధానం: A.
-
Question 5 ప్రశ్న 5Answer: C. At the inner surface సమాధానం: C.
-
Question 6 ప్రశ్న 6Answer: A. σr = -12 MPa and σθ = 31.2 MPa సమాధానం: A.
-
Question 7 ప్రశ్న 7Answer: B. σr = 0 and σθ = 19.2 MPa సమాధానం: B.
-
Question 8 ప్రశ్న 8Answer: A. σr = -4.224 MPa and σθ = 23.424 MPa సమాధానం: A.
-
Question 9 ప్రశ్న 9Answer: A. A = 9.6 MPa and B = 216000 MPa·mm² సమాధానం: A.
-
Question 10 ప్రశ్న 10Answer: A. 34 MPa at the inner surface and 19 MPa at the outer surface సమాధానం: A.
-
Question 11 ప్రశ్న 11Answer: A. σr = -10.28 MPa and σθ = 24.28 MPa సమాధానం: A.
-
Question 12 ప్రశ్న 12Answer: A. At r = 80 mm: σr = 0, σθ = -36 MPa; at r = 120 mm: σr = -10 MPa, σθ = -26 MPa సమాధానం: A.
-
Question 13 ప్రశ్న 13Answer: C. 38.46 MPa సమాధానం: C.
-
Question 14 ప్రశ్న 14Answer: C. 129.1 mm సమాధానం: C.
-
Question 15 ప్రశ్న 15Answer: A. The constant B decreases because it is proportional to pi - po, and the circumferential stresses at both the inner and outer surfaces decrease. సమాధానం: A.
-
Question 16 ప్రశ్న 16Answer: A. σr = σθ = -p throughout the wall సమాధానం: A.
-
Question 17 ప్రశ్న 17Answer: B. σθ + σr సమాధానం: B.
-
Question 18 ప్రశ్న 18Answer: A. σθ - σr = 2B/r² సమాధానం: A.
-
Question 19 ప్రశ్న 19Answer: B. 141.4 mm సమాధానం: B.
-
Question 20 ప్రశ్న 20Answer: B. 9.6 MPa tension సమాధానం: B.
-
Question 21 ప్రశ్న 21Answer: A. σr = -8 MPa and σθ = 13.33 MPa సమాధానం: A.
-
Question 22 ప్రశ్న 22Answer: C. 10.67 MPa సమాధానం: C.
-
Question 23 ప్రశ్న 23Answer: B. 1, 2 and 3 only సమాధానం: B.
-
Question 24 ప్రశ్న 24Answer: A. 1-R, 2-P, 3-S, 4-Q సమాధానం: A.
-
Question 25 ప్రశ్న 25Answer: B. Internal pressure = 12 MPa and bore hoop stress = 20 MPa సమాధానం: B.
