In today’s automobile scenario two wheelers are at high rate of sales. The road accidents are happening frequently everywhere. This makes every person to wear a helmet to avoid head injuries. But due to the difficulties like sweating, hair fall every person hesitates to wear helmet even though rules are put by the government.
In this paper we develop most sophisticated design of helmet. The head size and profile of every person is different. The standard size available does not fit perfectly for many people. So we make CF linear which perfectly assemble into the helmet. This can be made for individuals separately and it also consists of small holes which increases air circulation and reduce the weight of the helmet and makes comfortable for the rider.
PRODUCT DESIGN AND DEVELOPMENT
(DESIGN OF HELMET)
The process of developing a product from initial stage of Design to Physical Reality using concept of Designing, manufacturing processes and other economical aspects OBJECTIVES:
The objectives of product development are as follows…..
1. Converting Design into Physical Reality
2. Design optimization of the product
3. Manufacturing optimization of the products
4. Economically applying on product to optimize it 5. Market the product
MOTORBIKE HELMETS – CF DEMO CASE
THE CONSIDERABLE VALUE OF A CUSTOMISED HELMET:
The helmet will be more comfortable
➢ The helmet is more bearable and so riders will be less inclined to go without one. The helmet will give better protection:
➢ Less risk to be pulled off
➢ Crash forces are more evenly across the skull
➢ Customizing the helmets make them higher value and easier to sell.
➢ It increases the sense of ownership and pride in that product which increases brand loyalty.
➢ It also ensures that the customer makes a commitment to the product before a helmet is fabricated. HELMET COMPOSED OF:
➢ outer shell which is manufactured from either thermoplastic or fibre reinforced plastic composite – inner liner formed from expanded polystyrene (EPS) ➢ a comfort padding which is soft and low-density Foam
PART BEING CUSTOMISED
The original idea was to customize Inner EPS liner BUT we cannot use
EPS in RM So… A new CF liner was inserted between EPS and padding
– Safety still guaranteed by EPS and outer shell – Custom part is smaller (faster/cheaper to be manufacture via RM)
• 5% of motorcyclists cannot find helmets that fit their head geometry • 15-20% of all full face composite helmets are ill fitting • Helmet designed to absorb and disperse impact during an accident – The outer shell stops instantly.
– Inside, your head keeps going until it collides with the EPS. – EPS’s job is to bring the head to a gentle stop (if you want your brain to keep working like it does now.
Legal limitations on the volume that we can change within Custom-Fit and stay within the standard’s parameters CF LINER:
A new part between existing padding (comfort) and EPS* (safety).
PROCEDURE CUSTOM-FITTING HELMET
DATA FROM RIDERS:
• Scan of the rider (position of head!)
• Trim & repair,
• Align & landmarks
• Export geometrical and non-geometrical data
• DURING PRODUCTION
• Import the data
• Automatically chooses best fitting
• helmet size (S/L)
• Positions head inside helmet
• Creates surface of head geometry
• Morphs head/helmet geometry to
• shape CF Liner
• Split in 5 parts
• Internal structure applied
– Mimic EPS (apply to standards)
– Reduce weight
• Export STL files for RM
CUSTOMIZED MOTORCYCLE HELMET WITH RM
COMPUTER AIDED VERIFICATION (CAV)
• Objective: To determine if a helmet with a Custom Fit comfort liner would indeed be safer than a standard helmet • All helmets have to pass a couple of physical safety tests before being allowed on the market (United Nations regulation no. 22) • Not all physical tests can be done in economically feasible way in CF helmets • Virtual testing required
• Analytical method utilized
• Complexity of CF comfort liner:
1. Low material complexity
Linear material models (Emodulus) 2. Low geometric complexity
Defining thickness of comfort liner is sufficient. 3. High environmental complexity
Complex load cases of both impact absorption and retention tests • The physical tests on which the comfort liner will have its influence are: 1. Impact absorption test. The peak acceleration must be less than 275 g 2. Head Injury Criterion (H.I.C.) less than 2400
3. Retention (detaching) test. The helmets’ rotation after the test must not exceed 30° [pic]
➢ Peak acceleration level: 252 g
➢ H.I.C.: 1470
➢ Rotation: 20°
1. Benchmark introduction: Comfort liner stiffness k=E/t, 2. where E is E-modulus and t thickness of comfort liner
3. By means of a trend study, k should always be in between 3×106[N/mm3]
Step 1: Rider Data Capture and Processing
• Head Scan: head geometry is captured in a point cloud (Body scanner – HS)
• Point cloud is worked (trim, repair, aligned) transformed in STL file (STL: Standard Triangulation Language)
Step 2: Design customization > a. Shape
The CF liner is shaped to fit to the virtual head geometry, with an automated procedure (Delcam–PowerShape).
Step 2: Design customization > b. Grading structure
Lattice structure to
– reduce weight
– improve shock absorption
Adding cooling channels to refresh
Step 2: Design customization > c. Virtual testing
FEA analysis is used to verify shock absorption behavior & fine tune lattice structure.
Plastic Powder Printing Process (PPP)
Step 3: Rapid manufacturing
CF liner model is sliced and sent to RM machine
RM process: newly developed PPP – Powder Printing Process
Material used: HDPE
Step 3: Final assembling
CF liner model is finally assembled with standard parts – EPS and Outer shell
– Comfort padding ready for testing!
Work in progress…
➢ CF liner material and lattice structure must be finalized in order to improve ➢ shock absorption behavior of complete stack (EPS+CF liner) ➢ This without increase in weight and volume!