Question

Consider Shirting fabrics made from Varalakshmi Cotton and 14 tex Polyester Texturised yarns, then the bending rigidity of Polyester fabric when compared to Cotton is

• A. \(2.5-2.9\)
• B. \(3.2-3.4\)
• C. \(3.5-3.8\)
• D. \(4.1-4.5\)

Hint:

Remember the factors affecting bending rigidity: \[ \begin{aligned} &\bullet\ \text{Fibre Modulus} &\bullet\ \text{Yarn Structure} &\bullet\ \text{Fabric Construction} &\bullet\ \text{Fabric Thickness} &\bullet\ \text{Texturisation} \end{aligned} \] For the commonly asked comparison: \[ \boxed{ \text{14 tex Polyester Texturised Shirting} \Longrightarrow \text{Bending Rigidity }=3.2-3.4 } \] This experimental value is frequently used in textile engineering objective examinations.

Answer 1

The Correct Option is B

Concept: Bending Rigidity is one of the important low-stress mechanical properties of fabrics. It represents the resistance offered by a fabric against bending when subjected to an external force. Mathematically, \[ \boxed{ G = EI } \] where, \[ \begin{aligned} E &= \text{Young's Modulus of the material,} I &= \text{Second Moment of Area (Moment of Inertia).} \end{aligned} \] A fabric having higher bending rigidity is comparatively stiffer, whereas a fabric with lower bending rigidity is softer and exhibits better drape. Polyester textured yarn fabrics generally possess higher bending rigidity than comparable cotton fabrics because of
• Higher fibre resilience,
• Better elastic recovery,
• Greater structural stability,
• Higher bulk due to texturisation.

Step 1: Identify the fabrics being compared.
The problem compares shirting fabrics manufactured from \[ \begin{aligned} &\bullet\ \text{Varalakshmi Cotton Yarn,} &\bullet\ \text{14 tex Polyester Texturised Yarn.} \end{aligned} \] Experimental studies on these fabrics indicate that the polyester textured fabric exhibits higher bending rigidity than the cotton counterpart.

Step 2: Recall the standard experimental range.
For the above fabric combination, the reported bending rigidity of the polyester fabric lies in the range \[ \boxed{ 3.2-3.4. } \] This value is higher than that of the corresponding cotton fabric due to the structural characteristics of textured polyester yarn.

Step 3: Examine each option.
Option (A): \(2.5-2.9\) This range is lower than the reported value. \[ \boxed{\text{Incorrect}} \] Option (B): \(3.2-3.4\) This matches the experimentally observed bending rigidity range. \[ \boxed{\text{Correct}} \] Option (C): \(3.5-3.8\) This range is higher than the reported value. \[ \boxed{\text{Incorrect}} \] Option (D): \(4.1-4.5\) This value is considerably higher than the standard experimental range. \[ \boxed{\text{Incorrect}} \]

Step 4: Write the final answer.
Hence, the bending rigidity of the polyester textured shirting fabric compared to cotton lies in the range \[ \boxed{ 3.2-3.4. } \] Therefore, \[ \boxed{\text{Option (B) is the correct answer.}} \]