21-06-2011, 10:46 AM
[attachment=14193]
1. Introduction
During recent years the main focus in whiplash research has been on rear-end impacts. Rear-end impacts have the largest risk of whiplash injury and therefore much effort is being spent on decreasing this injury risk. The total number of frontal whiplash cases may be higher, despite the smaller risk. Therefore, it is clear that also in frontal impact there is a need for improvement of whiplash protection.
In the first European Whiplash project the rear impact loading phase was the main focus. The research at the time was mainly limited to the loading phase of rear impact, since most of the proposed injury mechanisms assume whiplash to occur in the loading phase. On the other hand, some of the mechanisms of whiplash injury are suggested to originate from the rebound phase of rear impact. The rebound phase involves neck flexion, as in frontal impact. Therefore, the current research aims at reducing whiplash in frontal and oblique impact and studies the rear-end rebound phase. In the end a test method will be proposed for evaluation of seats and restraint systems with respect to their whiplash protection. In this evaluation stage also a dummy is needed in order to assess the protection of a system. Part of the current project is to recommend on a dummy design that can be used for this purpose. Resulting from the findings in this concept, design guidelines for safer seat and restraint system design will be proposed.
2. Concept
2.1 Whiplash Injury
Whiplash is a relatively common injury that occurs to a person's neck following a sudden acceleration-deceleration force, most commonly from motor vehicle accidents
Whiplash-a soft tissue injury to the neck-is also called neck sprain or neck strain. It is characterized by a collection of symptoms that occur following damage to the neck, usually because of sudden extension and flexion.
Hyperextension injury to the neck, often the result of being struck from behind, as by a fast moving vehicle in a car accident. Whiplash is a term used most often to describe the symptoms resulting from a car accident.
2.2 Whiplash Injury Reasons
In order to understand how a whiplash injury occurs, you need to understand the structure of your body. The main support structure of your body is your spine, which consists of interlocking bones called vertebrae. Each vertebra is separated by a tough sack of jelly, called a disc.
In minor cases, the quick jerk to the neck will only result is some muscle damage, which can heal. In more severe cases, the whiplash motion can strain and sometimes even rupture the squishy discs that separate the vertebrae. When the disc gets damaged, the injured person may experience extreme pain, numbness, tingling, and other unpleasant sensations in the neck.
2.3 Whiplash protection System
It is the type of protection system that had been implemented in the front seats of the four wheel vehicle in order to avoid the neck injury.
The WHIPS seat provides improved spinal support by virtue of its modified backrest characteristics and close proximity of the head restraint's position to the occupant's head.
WHIPS utilizes a specially designed hinge mount that attaches the back rest to the seat bottom,
3.Principle of Whiplash Protection System
The Main Principle of Anti Whiplash Seat is to minimizing the degree of accident in the neck due to rapid movement of head and to design the seat’s backrest and a head restraint that is sufficiently high and positioned close to the head are also important factors.
The principle is based upon the following parameters which has been explained below
1. The Principle of Active Head Restraints
Here when the force is exerted on the Seat from the head of the persons due to sudden acceleration, the special type of the mechanism in the restraints will helps avoiding the equal and opposite force that exerts from the seat
Before Exerting force After Exerting force
2.The Seat Design
The Seat will made up of Wire Frames which reduces the impact of the forces that exerts from the human body
3. Mechanism of the Seat
In an impact from the rear, immense force may be exerted on the vulnerable neck. The body is pushed forward and if the head does not accelerate together with the body, the neck can be over-stretched.
4. Methodology
4.1 Selection of type of the Head Restraints
4.11 Reactive head restraints – RHR
The RHR system was introduced in 1997 as the world's first active, anti-whiplash head restraint and is standard equipment in all car models. It also provides multiple adjustment points to allow the head restraint to be ideally positioned for most front-seat occupants. Real-life crash statistics show that necks injuries are one of the most common results of rear-end. The RHR system is designed to limit the head movement of the occupant during the impact, helping to reduce the risk of whiplash injuries. The system is entirely mechanical and is based on the lever principle. An upper padded support is connected to a pressure plate in the backrest of the seat. In some rear collisions, the occupant's body will be forced by the crash pulse into the backrest, which moves the pressure plate towards the rear. Subsequently, the head restraint is moved up and forward to "catch" the occupant's head before the whiplash movement can start.
4.12 Pendulum System
The whiplash protection system used on Saab and Audi vehicles is a mechanical pendulum. When the occupant moves rearward (back and into the seat), their torso pushes against a plate that moves the head restraint upward and forward. This reduces the distance between the occupant’s head, and the head restraint, along with providing support and reducing injury to the occupant’s head. Springs in the seat structure return the head restraint to its normal position after the collision.
1. Introduction
During recent years the main focus in whiplash research has been on rear-end impacts. Rear-end impacts have the largest risk of whiplash injury and therefore much effort is being spent on decreasing this injury risk. The total number of frontal whiplash cases may be higher, despite the smaller risk. Therefore, it is clear that also in frontal impact there is a need for improvement of whiplash protection.
In the first European Whiplash project the rear impact loading phase was the main focus. The research at the time was mainly limited to the loading phase of rear impact, since most of the proposed injury mechanisms assume whiplash to occur in the loading phase. On the other hand, some of the mechanisms of whiplash injury are suggested to originate from the rebound phase of rear impact. The rebound phase involves neck flexion, as in frontal impact. Therefore, the current research aims at reducing whiplash in frontal and oblique impact and studies the rear-end rebound phase. In the end a test method will be proposed for evaluation of seats and restraint systems with respect to their whiplash protection. In this evaluation stage also a dummy is needed in order to assess the protection of a system. Part of the current project is to recommend on a dummy design that can be used for this purpose. Resulting from the findings in this concept, design guidelines for safer seat and restraint system design will be proposed.
2. Concept
2.1 Whiplash Injury
Whiplash is a relatively common injury that occurs to a person's neck following a sudden acceleration-deceleration force, most commonly from motor vehicle accidents
Whiplash-a soft tissue injury to the neck-is also called neck sprain or neck strain. It is characterized by a collection of symptoms that occur following damage to the neck, usually because of sudden extension and flexion.
Hyperextension injury to the neck, often the result of being struck from behind, as by a fast moving vehicle in a car accident. Whiplash is a term used most often to describe the symptoms resulting from a car accident.
2.2 Whiplash Injury Reasons
In order to understand how a whiplash injury occurs, you need to understand the structure of your body. The main support structure of your body is your spine, which consists of interlocking bones called vertebrae. Each vertebra is separated by a tough sack of jelly, called a disc.
In minor cases, the quick jerk to the neck will only result is some muscle damage, which can heal. In more severe cases, the whiplash motion can strain and sometimes even rupture the squishy discs that separate the vertebrae. When the disc gets damaged, the injured person may experience extreme pain, numbness, tingling, and other unpleasant sensations in the neck.
2.3 Whiplash protection System
It is the type of protection system that had been implemented in the front seats of the four wheel vehicle in order to avoid the neck injury.
The WHIPS seat provides improved spinal support by virtue of its modified backrest characteristics and close proximity of the head restraint's position to the occupant's head.
WHIPS utilizes a specially designed hinge mount that attaches the back rest to the seat bottom,
3.Principle of Whiplash Protection System
The Main Principle of Anti Whiplash Seat is to minimizing the degree of accident in the neck due to rapid movement of head and to design the seat’s backrest and a head restraint that is sufficiently high and positioned close to the head are also important factors.
The principle is based upon the following parameters which has been explained below
1. The Principle of Active Head Restraints
Here when the force is exerted on the Seat from the head of the persons due to sudden acceleration, the special type of the mechanism in the restraints will helps avoiding the equal and opposite force that exerts from the seat
Before Exerting force After Exerting force
2.The Seat Design
The Seat will made up of Wire Frames which reduces the impact of the forces that exerts from the human body
3. Mechanism of the Seat
In an impact from the rear, immense force may be exerted on the vulnerable neck. The body is pushed forward and if the head does not accelerate together with the body, the neck can be over-stretched.
4. Methodology
4.1 Selection of type of the Head Restraints
4.11 Reactive head restraints – RHR
The RHR system was introduced in 1997 as the world's first active, anti-whiplash head restraint and is standard equipment in all car models. It also provides multiple adjustment points to allow the head restraint to be ideally positioned for most front-seat occupants. Real-life crash statistics show that necks injuries are one of the most common results of rear-end. The RHR system is designed to limit the head movement of the occupant during the impact, helping to reduce the risk of whiplash injuries. The system is entirely mechanical and is based on the lever principle. An upper padded support is connected to a pressure plate in the backrest of the seat. In some rear collisions, the occupant's body will be forced by the crash pulse into the backrest, which moves the pressure plate towards the rear. Subsequently, the head restraint is moved up and forward to "catch" the occupant's head before the whiplash movement can start.
4.12 Pendulum System
The whiplash protection system used on Saab and Audi vehicles is a mechanical pendulum. When the occupant moves rearward (back and into the seat), their torso pushes against a plate that moves the head restraint upward and forward. This reduces the distance between the occupant’s head, and the head restraint, along with providing support and reducing injury to the occupant’s head. Springs in the seat structure return the head restraint to its normal position after the collision.
