AUTOMOBILE GLASS
description
Transcript of AUTOMOBILE GLASS
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AUTOMOBILE GLASSAUTOMOBILE GLASS
With Thanks ToJerry Chisum
Author:
“Evidence and Crime Scene Reconstruction”
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SHOOTING CAR WINDOWS SHOOTING CAR WINDOWS
American automobiles have two types of window glass. The windshield is laminated.
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SHOOTING CAR WINDOWS SHOOTING CAR WINDOWS
American automobiles have two types of window glass. The windshield is laminated, the rest is stressed safety glass. Each acts differently upon breaking.
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DID THE IMPACT COME FROM INSIDE OR OUTSIDE? DID THE IMPACT COME FROM INSIDE OR OUTSIDE?
When regular glass is impacted the resulting fracture spreads out as it moves away from the site of impact.
Note how the angles spread outward forming a cone
Side View
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DID THE IMPACT COME FROM INSIDE OR OUTSIDE? DID THE IMPACT COME FROM INSIDE OR OUTSIDE?
With laminated glass the fracture spreads out normally, but only on the front side.
Laminate spreads out the energy.
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All breaks radiate from one point. Primary lines lead to impact point.
POINT OF IMPACTStressed Glass
POINT OF IMPACTStressed Glass
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*First shot causes lines to radiate out and fracture the glass into many small pieces.
SEQUENCE OF SHOTSStressed Glass
SEQUENCE OF SHOTSStressed Glass
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*First shot causes lines to radiate out and fracture the glass into many small pieces.
*Subsequent shots only break the small pieces. Only first shot can be traced.
SEQUENCE OF SHOTSStressed Glass
SEQUENCE OF SHOTSStressed Glass
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O The first shot sends out radial lines 2nd shot lines may over extend 1st The shock wave, carried by the
plastic causes 1st lines to grow.
SEQUENCE OF SHOTSLaminated Glass
SEQUENCE OF SHOTSLaminated Glass
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O The first shot sends out radial lines 2nd shot lines may over extend 1st The shock wave, carried by the
plastic causes 1st lines to grow.
Like this...
SEQUENCE OF SHOTSLaminated Glass
SEQUENCE OF SHOTSLaminated Glass
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SEQUENCE OF SHOTSLaminated Glass
SEQUENCE OF SHOTSLaminated Glass
First Shot
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SEQUENCE OF SHOTSLAMINATED GLASS
SEQUENCE OF SHOTSLAMINATED GLASS
SECOND SHOT
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SEQUENCE OF SHOTSLAMINATED GLASS
SEQUENCE OF SHOTSLAMINATED GLASS
THESHOCK WAVE
EFFECT
But which shot occurred first?
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SEQUENCE OF SHOTSLAMINATED GLASS
SEQUENCE OF SHOTSLAMINATED GLASS
THESHOCK WAVE
EFFECT
But which shot occurred first?
Beats me!
?
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SEQUENCE OF SHOTSLAMINATED GLASS
SEQUENCE OF SHOTSLAMINATED GLASS
THESHOCK WAVE
EFFECT
With LAMINATED GLASS You Just Can’t Tell!
Beats me!
?
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ONE SIDED BREAK ONE SIDED BREAK
LAMINATED ONLY A “star shaped”
break on only one of the glass panes may be made by striking the opposite side.
Tap a dowel with a hammer, the opposite side breaks.
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GLASS - VIDEO CLIPSGLASS - VIDEO CLIPS
Density Testing
Density Testing + CA
Hackle Marks
Press Alt–Enter to view video in Full Screen ModePress Alt–Tab to return to this slide.
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GLASS - Hackle MarksGLASS - Hackle Marks
Let’s see if you really understand the “hackle Marks” video… you think the suspect in a case broke his own window from the OUTside of the house in order to fake a burglary.note: this is NOT the same as in the video write an “if” / “then” hypothesis showing How you can prove it using glass hackle marks.
Let’s see if you really understand the “hackle Marks” video… you think the suspect in a case broke his own window from the OUTside of the house in order to fake a burglary.note: this is NOT the same as in the video write an “if” / “then” hypothesis showing How you can prove it using glass hackle marks.
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GLASS - Hackle MarksGLASS - Hackle Marks
hypothesis:
If the impact occurred to the glass surface on the outside of the house,
hypothesis:
If the impact occurred to the glass surface on the outside of the house,
then … then …
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GLASS - Hackle MarksGLASS - Hackle Marks
hypothesis:
If the impact occurred to the glass surface on the outside of the house,
hypothesis:
If the impact occurred to the glass surface on the outside of the house,
then the hackle marks would be at right angles to the glass surface on the inside of the house.
then the hackle marks would be at right angles to the glass surface on the inside of the house.
OUTIN
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GLASS - Hackle MarksGLASS - Hackle Marks
hypothesis:
If the impact occurred to the glass surface on the outside of the house,
hypothesis:
If the impact occurred to the glass surface on the outside of the house,
then the hackle marks would be at right angles to the glass surface on the inside of the house.
then the hackle marks would be at right angles to the glass surface on the inside of the house.
IN OUT
RibMarks
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GLASS - Hackle MarksGLASS - Hackle Marks
hypothesis:
If the impact occurred to the glass surface on the outside of the house,
hypothesis:
If the impact occurred to the glass surface on the outside of the house,
then the hackle marks would be at right angles to the glass surface on the inside of the house.
then the hackle marks would be at right angles to the glass surface on the inside of the house.
OUTIN
RibMarks
Inside Outside
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GLASS - Hackle MarksGLASS - Hackle Marks
hypothesis:
If the impact occurred to the glass surface on the outside of the house,
hypothesis:
If the impact occurred to the glass surface on the outside of the house,
then the hackle marks would be at right angles to the glass surface on the inside of the house.
then the hackle marks would be at right angles to the glass surface on the inside of the house.
OUTIN
RibMarksHackle
Marks
Inside Outside
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GLASS - Hackle MarksGLASS - Hackle Marks
hypothesis:
If the impact occurred to the glass surface on the outside of the house,
hypothesis:
If the impact occurred to the glass surface on the outside of the house,
then the hackle marks would be at right angles to the glass surface on the inside of the house.
then the hackle marks would be at right angles to the glass surface on the inside of the house.
OUTIN
RibMarksHackle
Marks
Inside
90º
Outside