The radiating lines are appropriately known as radial fractures, and the cir cular lines are termed concentric fractures. Radial Fracture - A crack in a gloss that extends outward like the spoke of a wheel from the point at which the glass was struck.
What is rad radial fracture in glass?
Radial Fracture - A crack in a gloss that extends outward like the spoke of a wheel from the point at which the glass was struck. Concentric Fracture - A crack in a glass that forms a rough circle. Often it is difficult to determine just from
What are radial fractures and circles?
The radiating lines are appropriately known as radial fractures, and the circular lines are termed concentric fractures. Radial Fracture - A crack in a gloss that extends outward like the spoke of a wheel from the point at which the glass was struck.
What causes the formation of radial lines in glass?
As the first fractures form on the surface opposite that of the penetrating force, and these fractures develop into radial lines. The continued motion of the force places tension on the front surface of the glass, resulting in the' formation of concentric cracks.
What are the different types of glass fractures?
Radial Fracture - A crack in a gloss that extends outward like the spoke of a wheel from the point at which the glass was struck. Concentric Fracture - A crack in a glass that forms a rough circle.
What causes radial fractures in glass?
RADIAL FRACTURE: the penetration of ordinary window glass by a projectile, whether it is bullet or stone, produce a fracture pattern which radiates outwards like a spoke of wheel from the point at which glass was stuck.
Where are radial fractures in glass?
Radial Fracture - A crack in a gloss that extends outward like the spoke of a wheel from the point at which the glass was struck.
What are the 2 types of glass fractures?
When a projectile i.e. a bullet or rock hits the glass, it will form two distinct types of fractures: Radial and Concentric.
What does a radial fracture look like in glass?
Radial fractures are similar to the spokes of a wheel. Concentric fractures connect the radial fractures in a pattern similar to a spider web. The next step is to figure out which side of the fragment was facing in and which side was facing out.
What is radial crack?
Radial cracks are fractures extending outward from the point of impact. Ream is an imperfection; nonhomogeneous layers of flat glass. Wallner lines (ridges) are rib-shaped marks with a wave-like pattern.
What is the difference between concentric and radial glass fractures?
a. In a radial glass fracture, the fracture lines move outward from the point of impact. In a concentric glass fracture, the fracture lines occur in circles that share a center (the center is found at the point of impact).
What is rib marks in glass?
Stress lines/ Heckle marks/ Rib marks The edges of broken pieces of glass contain curved lines which are known as stress lines. These are always perpendicular to the side on which blow is struck. Heckle marks are small straight lines which can be observed in the broke edge of glass.
Which glass fracture occurs first?
Radial fracturesYou can see how the glass is stretched. This stretching causes the concentric fractures. Radial fractures occur first on side OPPOSITE the force. Concentric fractures occur second on SAME side as force.
What are radial cracks How do they help determine the direction of impact of an object on glass?
Concentric fracture- A crack in a glass that forms a rough circle around the point of impact. By analysing the radial and concentric fracture pattern in glass, the forensic scientist can determine the direction of impact by applying the 3R rule: Radial cracks form a Right angle on he Reverse side of the force.
How long does it take for a radial fracture to heal?
Depending on how severe your fracture is and on other factors, you may not have full range of motion after you recover. Most fractures heal well in 6 to 8 weeks.
How serious is a radial head fracture?
In most Type III radial head fractures, there is also significant damage to the elbow joint and the ligaments that surround the elbow. Surgery is always required to either fix or remove the broken pieces of bone and repair the soft-tissue damage. If the damage is severe, the entire radial head may need to be removed.
How do you treat a fractured radius?
Nonsurgical Treatment If the distal radius fracture is in a good position, a splint or cast is applied. It often serves as a final treatment until the bone heals. Usually a cast will remain on for up to six weeks. Then you will be given a removable wrist splint to wear for comfort and support.
Why is window glass prone to thermal fracture?
In framed window glass, the edges are relatively cooler than the exposed areas, so space heating devices in very close proximity may cause thermal fracture.
What causes thermal fracture?
It is caused by damage to the edge of the glass. This weakens the edge, so less stress is required to cause the failure. The probability of this type of thermal fracture cannot be determined using thermal assessment processes. High energy: These are rare and require high levels of thermal stress.
Which is stronger, polished or clean cut glass?
Clean cut glass is the strongest and after that polished edge is strongest. Artificial heating and cooling: if heating or cooling vents are present, the glass can heat or cool excessively and may result in thermal stress.
What is a radial crack?
Terminology - • Radial cracks are fractures extending outward from the point of impact. • Concentric cracks are fractures forming in an approximately circular pattern around the point of impact. They are usually in straight segments that terminate in an existing radial crack.
Why are glass fractures important?
Significance of glass and glass fracture evidences • To aid reconstruction of crime scene • To provide information about the events which took place , and assisting in proving or disproving a witness’s story. • Glass fracture patterns are associated with burglary, criminal mischief, shooting incidents, and fire scenes.
What happens to glass after a force?
10. • After a striking force, glass first bends in the direction of applied force due to elasticity. • When the elastic limit exceeds, glass begins to crack beginning with the formation of a radial crack or fracture on the surface opposite to the penetrating force.
What were the pieces of glass found on Craig's jacket?
Pieces of glass were found on Craig's jacket and around his body at the crime scene. These pieces of glass helped crime scene investigators figure out what happened. Police searched for a vehicle that had the same damage as the hit and run car. Then they found a car with those damages that belonged to Susan Nutt.
How to compare color of glass?
Comparing colour can distinguish between two or more sources of glass. side-by-side comparisons should be made with fragments of approximately equal and sufficient size. The fragments should be visually compared on edge, over a white surface, using natural light.
Did Susan Nutt's windshield contain the same chemicals as her car?
This job was done by researchers at Oregon State University's Radiation Center. The scientists there found that the windshield glass contained the same 22 chemicals as the ones in Susan's car. They also said that both samples of glass were a definite match. The glass evidence helped convict Susan Nutt.
Overview
Thermal fracturing in glass occurs when a sufficient temperature differential is created within glass. As a warmed area expands or a cooled area contracts, stress forces develop, potentially leading to fracture. A temperature differential may be created in many ways, including solar heating, space heating devices, fire, or hot and cold liquids. Sloping glass surfaces are subject to greater solar radiation than vertical surfaces and so are more prone to solar thermal fracture. In f…
Factors affecting thermal stress
• Solar absorption: the temperature of glass depends on the amount of heat absorbed by the glass. So a high performance solar control glass will absorb more heat. so it will be more prone to thermal fracture
• Shadow: the presence of shadows will result in relatively cooler areas in glass. Thus it results in temperature difference and may result in thermal fracture.
Different types of thermal fracture
• Low energy: Most common type of fractures. It is caused by damage to the edge of the glass. This weakens the edge, so less stress is required to cause the failure. The probability of this type of thermal fracture cannot be determined using thermal assessment processes.
• High energy: These are rare and require high levels of thermal stress. The probability of this type of thermal fracture can be determined using thermal assessment processes.
Prevention of thermal fracture
• Low energy: edges of annealed laminated glasses are polished. Inspection is done to find damages in glass.
• High energy: glasses are heat strengthened to avoid high energy thermal failure.