Warhead Nose Ribs Mitigate J Effect Torque
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Solution Overview
Problem
Unguided warheads face challenges in penetrating hard targets at oblique angles due to the 'J Effect', which causes rotation, reduced penetration depth, ricocheting, and increased loads on the fuse, leading to structural failures and decreased effectiveness, especially when striking shallow or multi-layered targets.
Innovation Solution
A warhead nose design featuring structural ribs along the circumference, which reduces stress and drag resistance, allowing for deeper penetration and minimizing the 'J Effect' by creating opposing forces that balance torque, thus preventing ricochets and maintaining fuse reliability across various angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conical or ogive nose is used to reduce resistance forces and guide penetration, then penetration capability is improved, but the J Effect causes rotation and ricochet at oblique angles
Solution Approach 1:
The patent applies asymmetry by adding circumferential ribs to the conical nose, creating an asymmetric structure that generates opposing forces to counteract the J Effect rotation moment. The ribs are positioned at specific angles and have varying cross-sections to create balance forces that prevent warhead rotation during oblique penetration.
Solution Approach 2:
The patent uses the counterweight principle by designing ribs that generate opposing forces (counter-moments) to balance the J Effect torque. The ribs create resistance forces on the opposite side of the rotation moment, effectively counteracting the rotational tendency and stabilizing the penetration path.
2Reliability
If warhead structure is strengthened by increasing metal thickness to withstand J Effect loads, then structural reliability is improved, but weight increases
Solution Approach 1:
The patent applies segmentation by dividing the nose structure into a conical body with circumferential ribs. This segmented structure provides enhanced strength and stiffness to resist J Effect loads while using less material than a solidly thickened nose, thereby reducing weight compared to conventional strengthening approaches.
Solution Approach 2:
The patent uses composite structural design by combining the conical nose body with circumferential ribs made of high-strength materials. This composite structure achieves superior strength-to-weight ratio, providing the necessary structural reliability to withstand J Effect loads without significant weight increase.
3Reliability
If a blunt nose is used to reduce the J Effect by creating opposing forces, then rotation is reduced, but drag forces increase significantly
Solution Approach 1:
The patent applies local quality by adding ribs only to specific locations on the conical nose surface rather than changing the entire nose shape to blunt. The ribs are positioned circumferentially at optimized locations to generate counter-forces where needed, maintaining the streamlined conical shape for low drag while providing local stability enhancement.
Solution Approach 2:
The patent uses parameter changes by modifying the nose geometry through added ribs with specific dimensions, angles, and spacing. The ribs have optimized cross-sectional areas and orientations that generate sufficient counter-moments to reduce the J Effect while minimizing their impact on drag forces, achieving a balance between stability and penetration efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The warhead nose design enhances durability and penetration capability without significant weight increase, allowing for straight penetration through multiple layers at various angles, reducing side forces and torques, and maintaining fuse reliability.
Implementation Method 1
asymmetrical forces develop on the conical or ogive nose. Such forces create a rotation moment (torque) around the center of mass of the warhead and cause the warhead to move in a bent line
Implementation Method 2
The ribs reduce the drag forces acting on the warhead during penetration by creating opposing forces that balance the torque
Data Source
Figure 1A~1C
Figure 2A~2C
Figure 3~4
AI summary
A warhead nose comprises a conical/ogive body having an outer surface with a top circumference and base circumference, and ribs extending along the outer surface of the conical/ogive body tapering so that the circumference around the ribs is smaller than or equal to the circumference of the base, the warhead nose dimensions are determined by the following relations: where, D is maximum nose diameter; E is external diameter of the ribs; F is length of the ribs along the nose; G is minimal width of the ribs; H is height of the rib protrusion; and I is the minimal width of the rib at the adjoining point with the nose.