Section Modulus calculation and optimization

SECTION MODULUS OF HOOD

AIM:

To find the section modulus for a given hood and also to get improved value of the section modulus by applying necessary requirement according to the design parameters.

INTRODUCTION:

Section modulus is a geometric property for a given cross-section used in the design of beams or flexural members. Other geometric properties used in design include area for tension and shear,radius of gyration for compression, and moment of inertia and polar moment of inertia for stiffness. Any relationship between these properties is highly dependent on the shape in question. Equations for the section moduli of common shapes are given below.

SECTION MODULUS:

The elastic section modulus is defined as

S = I / y

where I is the second moment of area (or area moment of inertia, not to be confused with moment of inertia) and y is the distance from the neutral axis to any given fibre. It is often reported using y = c, where c is the distance from the neutral axis to the most extreme fibre, as seen in the table below.

SECTION MODULUS ITERATION PERFORMANCE OVER ENGINE HOOD:

Case 1:

Section modulus iteration performance for original design engine hood

• section modulus calculation of the maximum moment of inertia

(I_MAX) moment of inertia = 8.858203021e⁷ (mm⁴)

(Y) = 436.977 (mm)

S = I / y

S = 8.858203021e⁷/ 436.977

S_MAX = 202715.543 mm³

• section modulus calculation of the minimum moment of inertia

(I_MIN) moment of inertia = 2.520362109e⁵ (mm⁴)

(Y) = 436.977 (mm)

S = I / y

S = 2.520362109e⁵ / 436.977

S_MIN = 576.77 mm³

Case 2:

Section modulus iteration performance for engine hood which is 1.5 mm offset at the hood inner panel.

• section modulus calculation of the maximum moment of inertia

(I_MAX) moment of inertia = 8.858749519e⁷ (mm⁴)

(Y) = 436.977 (mm)

S = I / y

S = 8.858749519e⁷ / 436.977

S_MAX = 202728.050 mm³

• section modulus calculation of the minimum moment of inertia

(I_MIN) moment of inertia = 2.691205651e⁵ (mm⁴)

(Y) = 436.977 (mm)

S = I / y

S = 2.691205651e⁵/436.977

S_MIN = 615.868 mm³

CONCLUSION:

The comparison between the Case 1 and Case 2 are done. The section modulus value of case 2 is higher than the case 1. As we increase the section area the moment of inertia and section modulus increases which means strength and load capacity of material also increased from case 1 to case 2.