Slam Analysis Abi

  • View
    107

  • Download
    3

Embed Size (px)

Text of Slam Analysis Abi

Slam Analysis for ClosuresClick to edit Master subtitle style

Presenter Abi Swaminathan5/30/12

Content Introduction Types of Closures Hood Slam Analysis Hood Assembly Boundary Conditions Loading Condition Target for Slam Analysis Transient Response Analysis Analytical Procedure

5/30/12

IntroductionDoors are hanged on parts should fulfill diverse requirements over their complete life time. The main function of hang on parts is to open and close the car. The damage to the components of the closures induced by the slam , accumulates over the vehicle lifetime and may lead to failure.5/30/12

Types of ClosuresHood Decklid Hatchback Tailgate Side

door Sliding Door

5/30/12

Types of Closures

5/30/12

Hood Slam AnalysisHood

opening/closing is a necessary function in a vehicle. But the closing often results in an impact known as hood slam. Impact loads special case of dynamic loads that occur when there is a sudden change in velocity. Dynamic loads- Force generated when the5/30/12 vehicle is in motion

Hood Slam AnalysisThe

hood slam load- Rotational velocity applied to the hood in the open position. When the hood reaches the closed (latched) position, Striker contacts the latching mechanism. periphery of the hood contacts seal(s) and bumpers. Then sudden impulse results in 5/30/12

Hood AssemblyIt includes fully trimmed closures. Body in white front structure cut line with SPC Inner and Outer Panels Hinge assembly Door structural members Latch/ Striker Adhesive, Hem, Mastic and welds Seal5/30/12

Hood Assembly

hood inner b) hood outer c) main reinforcement d) hood hinge reinforcement e) latch reinforcement f) assembly without the outer panel.a)

5/30/12

Hood AssemblyLatch Mechanism which catches, holds, and releases the striker in hood closing and locking systems Found on door side in doors, decklids, and tailgates and on body side in hoods Striker Small bar on door side of latch mechanism which strikes the latch on closure and is then held in place until the latch is released Found on body side in doors, decklids, and tailgates and on door side in hoods 5/30/12

Hood AssemblyWeather-strip seal: Rubber seal found around doors, glass, and deck lid openings to prevent seepage of water into the vehicle interior

5/30/12

Hood AssemblyHood Bumper:This bumper is used on the radiator support and is adjustable in order to help get the correct panel alignment at the front of the hood. They also help reduce rattles by minimizing metal-to-metal contact.

5/30/12

Boundary Conditions:The

body side hinges -all six degrees of freedom. The latch attachment - all six degrees of freedom. Bumpers -all six degrees of freedom. Seals -all six degrees of freedom.5/30/12

Loading ConditionApply

initial angular velocity to all rotating closure parts about hinge pivot.

Angular

velocity based on the hood geometry w(omega)= V / r where : w= hood rotational velocity about the hinge pin centerline 5/30/12

Target for Slam Analysis:Body

& Door should provide clearance for Over slam . product will meet customer expectations for reliable service under anticipated usage conditions for the useful life of the vehicle.5/30/12

The

Typical Hood over travel response curve:Initial velocity: calculated from height of fall calculation time: approximately up to 2 ms after reversal point Dis pl a c e m e nt ( m m )

Time(sec) 5/30/12

TRANSIENT RESPONSE ANALYSIS (NASTRAN SOL.129)Transient

response or natural response is the response of a system to a change from equilibrium. Its purpose is to identify areas of the hood structure subject to high stress, quantify latch, striker, bumper, and hinge loads, and calculate the structural fatigue 5/30/12 damage due to a door impact.

Transient solution Equation Transient solution uses the following equation and evaluates the structural response with a fixed integration time step (t)

[M]* {u"(t)}+5/30/12

Analytical Procedure:

5/30/12

Analytical Procedure:

5/30/12

Analytical Procedure:

5/30/12

Analytical Procedure:

5/30/12

Thank You

5/30/12