Issuu

VIII

https://doi.org/10.22214/ijraset.2021.37308

August 2021

Design and Fabrication of Safety Impact Guard Sachin Nikam1, Hemant Swakarnar2 1

PG student, 2Professor, Dept of Mechanical Engineering, Kavayatri Bahinabai Chaudhari North Mahrashtra Univerity

Abstract: Death due to Accidents are greater than natural disaster and terror attack in India. One of the most injurious cases is the crash between car and heavy vehicle. Every year lacks of passengers are killed due to road accidents in which 8% are due to heavy vehicles. Road accident causes loss of life and also property. Accidents can not be avoided completely but the impact force is decreased by application of Design and Fabrication of safety impact guard. Safety impact guard is protecting device used to reduce collision impact at rear end of heavy vehicle when accident occurs. Keywords: Impact, Crushing Element, Safety Impact Guard, Underride I. INTRODUCTION When a road accident between a car and a heavy vehicle happens, all the protection features for the occupants built into the car, such as seatbelts and airbags, have a reduced effectiveness. This because of the very big differences in geometry and stiffness between the two vehicles. The very large height of the truck, especially when the heavy vehicle is note quipped with a Safety Guard, it can allow the underride or also called underrun of the car. Many people get injured during under ride accidents. Because of high Collision impact between car and Heavy vehicle chassis, passenger present in car will cause death or seriously injured. To avoid such accidents safety guard has to be installed on the heavy good vehicle which would prevent the passenger of the small vehicle from getting fatal injuries. Without installation of the safety guard, entire energy will be on the frontal car structure which would not be able take such impact. The entire vehicle has gone underneath the truck and the car structure has got crushed due to the sudden impact load. Figure shows damage to small passenger vehicle during a rear under ride accident.

Fig. 1: Underride Crash of Car II. LITERATYRE SURVEY An Before going to direct design consideration about rear impact guard we will see some other concepts which are related directly or indirectly to working of rear impact guard. A. Page Layout Your Page Style A vehicle usually an automobile or a truck crashes into the vehicle in front of it. Factors responsible for rear-end collisions includes loss of attention or distraction of driver, work fatigue or continuous hours of driving, Insufficient front lighting of passenger vehicle also in rainy season presence of water on road surface results into reduced friction between vehicle and road responsible for rear end collision.Condition of roadways on which vehicles travel is also important reasons behind the cause of accident, poorer condition of roadways leads to increased severity of accident. One of major roadways which carry most of road traffic in India is National Highways which is described as below: According to NHAI, India’s total road network is of 56 lakh Km, which is second largest road network in the world. Out of total 56 lacks km road network National Highways constitute only 2% but National Highway carries majority of road traffic which is about 40%.Number of vehicles has been growing almost at an average pace of 10% per annum over the last five years. Increase in number of total Registered vehicle in India from 1951- 2016 is as shown in figure:2

©IJRASET: All Rights are Reserved

273

Recent Scenario of growth of population in India indicates that there is rapid increase in population over the last few decades. To fulfill the need of transportation of this increased population, number of vehicle goes on increasing. As explained earlier the reasons responsible for accidents and increased number of vehicles leads to increased in number of accidents. Therefore, to reduce number of accidents an underrun protecting device i.e. High Energy safety Impact guard is needed because of that we can save lives and prevent loss of property. Percentage of persons killed in total casualties in Road accidents during 2012-2017 is shown in Table Table 1: Percentage of Persons Killed in Total Casualties in Road Accidents during 2012-2017 Year 2013 2014 2015 2016 2017 All India 28.3 28.5 29.1 31.4 31.8 All paragraphs must be indented. All paragraphs must be justified, i.e. both left-justified and right-justified. B. Ground Clearance One of major reason behind the underrun crash is ground clearance of Heavy duty vehicle. The ground clearance provided in Heavy Duty vehicles is larger compare to small passenger vehicle. Because of that when collision between car and heavy vehicle happens the rear side of heavy vehicle cuts the upper part of passenger vehicle. i.e. underride of car happens which results into death or severe injury to passengers which present in car. C. Position of Rear Impact Guard Consider the case in which, Passenger vehicle like car is travelling at a certain speed and ahead of car a loaded heavy duty vehicle is running. Obviously since heavy vehicle is loaded it will travel at lower speed than that of passenger vehicle. In case if any obtrusion comes in front of heavy duty vehicle it will apply sudden brakes, due to that speed of heavy vehicle reduces immediately in fraction of seconds. Due to this driver of passenger vehicle could not get control over vehicle and car will undergo into beneath of heavy vehicle due to undercutting of upper part of passenger vehicle as shown in figure.3

Fig:3 Position of vehicle when crash going to happen To overcome the problem of underride crash, hollow bar is attached at the rear end of heavy duty vehicle which will act like solid body i.e. it does not have shock absorbing capability. At the time of collision the impact force by car is such a large that this bar is not able to absorb the shock and get damaged and allows under running of vehicle. Due to this problem High Energy safety Impact guard is attached to the rear end of Heavy duty Vehicle so that the underside crash should be avoided. Further new research and design modifications will be done and implemented.

©IJRASET: All Rights are Reserved

274

International Journal for Research in Applied Science & Engineering Technology (IJRASET) ISSN: 2321-9653; IC Value: 45.98; SJ Impact Factor: 7.429 Volume 9 Issue VIII Aug 2021- Available at www.ijraset.com III. RESEARCH METHODOLOGY The main objectives of this High energy safety impact guard is to avoid underride crashes and to reduce the impact force between passenger car and heavy duty vehicle so that life of passengers can be saved and also damages of vehicles can be prevented. With respect to our objective the proposed design of safety impact guard is as shown in figure.3

Fig. 4 Proposed Design of safety impact guard A. Inner Member This member is attached to the chassis of heavy duty vehicle at rear side using I section member, so that the clearance in between safety impact guard and ground is reduced therefore, underride crash is eliminated. As force is absorbed by the crushing element which is present in inner cylinder therefore effect of impact force on inner member as well as on chassis of heavy vehicle is reduced. Therefore, inner member act like a rigid body and net impact force experienced by heavy duty vehicle is negligible. B. Inner Cylinder This cylinder is attached on the inner member. This device consist of round plate, stopping element, crushing element,. The diameter of inner cylinder should be greater than the outer cylinder, so the outer cylinder slide in inner cylinder when impact force applied on it. C. Round Plate Round plate is inserted in inner cylinder and act as back support for inner member. Strength of inner member is increases due to round plate also it not allows the motion of outer member to go beyond inner member D. Connecting plate Connecting plate is used to connect the two inner members of safety guard in parallely. E. Stopping Element Stopping element is added in inner cylinder to restrict the motion of outer cylinder up to certain limit. When impact force acts on the outer member then it pushes outer cylinder into inner cylinder and allows sliding motion between inner and outer cylinder. This impact force very large therefore it is necessary to restrict this motion otherwise it will damage the inner member therefore stopping element is added. F. Outer Member The outer member is the element on which the impact force act when passenger vehicle strikes at rear end of heavy vehicle. G. Outer Cylinder This cylinder is attached on the outer member. The impact force is transmitted through the outer member to outer cylinder to the crushing element. The diameter of outer cylinder is less than the inner cylinder so that it can slide. For this project to design such type of safety impact guard two vehicle models are considered as follows: H. Heavy Duty Vehicle TATA LPS 3516EXPassengerVehicle: Huyndai i10 From the specification and dimension of above considered vehicles we can design some member of safety impact guard.

©IJRASET: All Rights are Reserved

275

International Journal for Research in Applied Science & Engineering Technology (IJRASET) ISSN: 2321-9653; IC Value: 45.98; SJ Impact Factor: 7.429 Volume 9 Issue VIII Aug 2021- Available at www.ijraset.com IV. DESIGN OF SAFETY IMPACT GUARD In mechanics, an impact is a high force applied over a short time period when two or more bodies collide. Impact Force = Kinetic Energy/ Impact Distance (1) Consider the impact distance for maximum case, for this project impact distance is consider as 0.5m. Kinetic Energy of a passenger vehicle is calculated as follows: Kinetic Energy = ½ mv2 (2) Where m = mass of passenger vehicle i.e car; v = velocity of passenger vehicle For sustaining all impact energy during collision we have to consider maximum impact force acting on heavy vehicle. For calculation of maximum impact force, consider maximum velocity of passenger vehicle allowed travelling on Indian highway is 80 km/hr. i.e. 22.23 m/sec. We have the passenger vehicle mass i.e. of Hyundai i10 1040 kg. Therefore the eqn. (2) becomes: K.E = ½ * 1040*(22.23)2 = 256.969*103 J Therefore equation (1) becomes: Impact Force =256.969*103/0.5 =513.939 KN Total force acting on both the members is 513.939KN. Therefore, force acting on single member is half of it i.e. 256.969KN. Impact Force 256.969KN have to sustain by safety impact guard. By using impact force we have to design the safety impact guard to sustain this much of force in reverse manner. We know the basic equation of stress which is: Stress = Force/Area Compressive area = 2055.756 mm2 Total force acting on both the members is 513.939KN. Therefore, force acting on single member is half of it i.e. 256.969KN. Impact Force 256.969KN have to sustain by safety impact guard. By using impact force we have to design the safety impact guard to sustain this much of force in reverse manner. We know the basic equation of stress which is: Stress = Force/Area Compressive area = 2055.756 mm2 Therefore the required compressive area of crushing element which is going to crush should be 2055.756 mm2. A. Design of Plate Thickness The Outer member will act like a overhang beam which is to be acted by uniformly distributed load.

Fig. 6: Loading Diagram of outer member To Find out Support Reactions RB and RC; ∑Fy = 0 RB + RC = 256.969 (I) To Find out RB ; Take Take ∑Moment at point B= 0 256.969 x 662 - RC x 1324 = 0 RC = 128.484 KN, Put this value of RB in Equation (I), we get; RB + 128.484 = 256.969 RB = 128.484 KN

©IJRASET: All Rights are Reserved

276

International Journal for Research in Applied Science & Engineering Technology (IJRASET) ISSN: 2321-9653; IC Value: 45.98; SJ Impact Factor: 7.429 Volume 9 Issue VIII Aug 2021- Available at www.ijraset.com B. Shear Force Calculations Shear Force at A = 0 Shear Force at BL = -105 x 558 = -58590 = -58.59 KN Shear Force at BR = 58590+128484= 69.894 x 103 = 69.894 KN Shear Force at CL = 69894 – (105 x 1324)= -69.126 x 103 = -69.126 KN Shear Force at CR = -69126 + 128484 = 59.358 x 103 = 59.358 KN Shear Force at D = 0 Shear Force at D = 0

Fig. 7: Shear Force Diagram of outer member C. Bending Moment Calculations MA = 0 M = -105 x 558 x 558 = -16.346 x 103 KNmm B

2 M = (-105 x 1882 x 1882 ) + (128484 x 1324) = -15.838 x103 KNmm C

MD = 0 1) Location of Maximum Bending Moment Let assume at a section x-x from point A; Bending Moment is Maximum Mx-x = -[105* x*x] + 128484*(x-558) Solving this equation; we get x = 1586mm from point A 2)

Maximum Bending Moment = -105*1586 * 1586 + 12848*(1586-558)

2 B.M. max = 23.262*103 KNmm 3)

Moment of Inertia of Plate

Fig. 8: Dimensions of outer member Plate

©IJRASET: All Rights are Reserved

277

bd3 12

2440t 3

12 I = 203.33 t3 mm4 Position of neutral axis from base y=

100

2 y = 50 mm Therefore, using Maximum Bending Moment and allowable stress we can calculate the thickness of plate : σ=

Mx ∗ y I

250 = t3 =

23.262∗106∗50 203.33t 3 23.622∗106∗50 250∗203.33

t3 = 28.33mm t ≈ 30 mm Therefore, thickness of outer member is selected as 30 mm and for inner member to increase its strength and rigidity thickness selected is 40mm.

D. Modelling and Assembly of Safety Impact Guard The Modelling and assembly of safety impact guard is done with help of in CATIA workbench. Design and parts for this model assembly was explained before. Assembly of High Energy safety impact guard consist of : - 2 Inner Member, 4 Inner Cylinder, 4 Round Plate, 2 Connecting Plate

Fig.9

278

International Journal for Research in Applied Science & Engineering Technology (IJRASET) ISSN: 2321-9653; IC Value: 45.98; SJ Impact Factor: 7.429 Volume 9 Issue VIII Aug 2021- Available at www.ijraset.com E. Design of Plate Thickness The Outer member will act like a overhang beam which is to be acted by uniformly distributed load. F. Calculation of Theoretical Stress: Stress In Coil (σ) Plain spring given data Type: Helical Compression Spring End Condition: Both End Squared and Ground. Rod Diameter: 5 mm Mean Coil Diameter: 21.8 mm Inner Diameter =17 mm Outer Diameter = 27 mm Number of Turns =5 Free Length =40 mm G = 80 X 103 Mpa

G. Calculation of Theoretical Stress: Stress In Coil (σ) σ = ×8× × × 3 Here, K= Stress factor = 1.19 ----calculated used spring index. σ= 1.19 × 8 × 246.3 × 21 π × 533 σth = 15.6 N/mm2 As σ th < σ allowable Thus spring is safe.

The detailing and assembly of High Energy safety impact guard is as shown in below: Fig.10: Detailing of assembly of safety impact guard

279

Fig.11: Modelling of assembly of safety impact guard

Fig12: Section View of Catia model of Safety Guard Above CATIA model is analyzed using for this project scope of analysis is limited to static structural. Displacement to the crushing element and outer member these boundary conditions are applied. when impact force acts on outer member then outer member displace to some distance inside of inner member due to crushing action. By giving the appropriate input parameters on the CATIA model i.e. fixed support, displacement to outer member, load application analysis of the safety impact guard is carried out. Above safety impact guard is analysed for 20% of force of total impact force which is 51393.9N Results for maximum stress values as follows: For this much of force stress acting on safety impact guard is 239MPa while permissible stress is 250MPa. Therefore this design is acceptable. In this design for 20% of load number of crushing element used in four. According to that for sustaining 80% loading condition crushing element should be used in number is sixteen. For sustaining 80% of load design of safety impact guard has to be change. Design changes are made as shown in next figure.

Fig.14: Detailing of assembly of safety impact guard designed for sustaining 80% of loading V. CONCLUSION High Energy Safety Impact Guard is one of the safety instruments which can reduce collision impact at rear end collision when accident occurs. Safety guard provides protection against under ride crashes by increasing striking area by using two outer members of safety guard. With respect to our objective design, modelling and analysis of High Energy safety impact guard is done. By implementing this safety impact guard life of passenger present in passenger cars can be saved and also passenger is saved from getting serious injuries, and vital parts of passenger vehicle i.e. engines etc. will be prevented from damage.

280

Neha S. Dixit and Dr. Ajay G. Chandak “Design, Model-ling & Analysis of Safety Impact Guard for Heavy Duty Vehicle‖” International Journal of Innovative Research in Advanced Engineering (IJIRAE) ISSN: 2349-2163 Volume 1 Issue 6 (July 2014). Juhilee Pawar and Prof. R.S.Shelke “Review paper on Design, Modelling and Analysis of Safety Impact guard with PRV Based Damper” International Journal of Scientific & Engineering Research, (ISSN 2229-5518)Volume 8, Issue 4, April-2017. Tapan Jain and Dr. Neeraj Kumar, “Analysis of Rounded Rear Under Run Protection Device of Heavy Vehicle Using Finite Element Analysis For Crashworthiness” International Journal Of Current Engineering And Scientific Research (IJCESR) ISSN: 2393-8374, Volume-5, Issue-1, 2018. Ravi Purushottam Mohod, “Crashing Analysis of Rear under Run Protection Device (RUPD)” Imperial Journal of Interdisciplinary Research (IJIR), ISSN: 2454-1362 Vol-3, Issue-9, 2017 Byron Bloch,“Improved crashworthy Design for truck underride Guards”, Unicamp state University, 2007 F. Cappello, T. Ingrassia & V. Nigrelli, “Design of a new high energy rear underrun protective device” WIT Transactions on The Built Environment, Vol 97, www.witpress.com, ISSN 1743-3509 Alok Kumar Khore,Tapan Jain and Prof. Kartikeya Tripathi, “Multidisciplinary Design Study of Heavy Vechical Rupd Crashworthiness Energy Absorption” (IOSRJEN) ISSN: 2250-3021,Vol.4, Issue Jan. 2014 N. Manikandan, B Prabhakaran, K Karthikeyan and D K Mohan Kumar, “Design and development of rear under ride protection device (RUPD) with improved energy absorption using ANSYS”, IOP Conf. Ser.: Mater. Sci. Eng. 402 012169 Mr. George Joseph, Mr. DhananjayShinde and Mr. Gajendra Patil, “Design and Optimization of the Rear Under-.Run Protection Device Using LS-DYNA” International Journal Of Engineering Research And Applications (IJERA) ISSN: 2248-9622 Vol. 3, Issue 4, Jul-Aug 2013. “Global Status Report on Road Safety 2018” by World Health Organisation, www.who.int. Annual Report on “Road Accidents in India – 2017” by Ministry of Road Transport & Highways “Basic Road Statistics of India - 2015-16” by National Highway Authority of India (NHAI) https://en.wikipedia.org/wiki/Rear-end_collision

281