Selection of an off-Highway Vehicle Using Customer Perspectives

Selection of an off-highway vehicle using customer perspectives

Pradeep Kumar Tarei* and Amitava Ray2

2Assistant Professor

Department of Mechanical Engineering. National Institute of Technology, Silchar.788010.INDIA[pic 1]

Abstract 

 The  selection of a proper  off-highway vehicle  plays a vital role especially  for a construction company . It requires the detail brain storming analysis of both customer and technical criteria .With the implementation of latest technologies   and a booming competitive market, it becomes a formidable task to select a suitable off-highway vehicle for a company which deals with the transportation of heavy stones, metal ores and other building materials in uneven roads and hazardous mining site. In this paper, using a combined AHP/QFD model, the authors are able to determine the proper selection of an “off-highway vehicle” for a construction company in order to maximize its productivity and profit. The adopted integrated approach considers five customer requirements such as Loaded body volume (LBV), Mileage, Price , Maximum speed  and robustness . Initially, the priority values are calculated for each of the customer requirement(CR) by using AHP . Meanwhile five technical requirements (TR) such as Gross vehicle weight(GVW), Maximum power , fuel tank capacity , Gear box and gradeability are chosen for a QFD analysis . An expert QFD team assigns a weightage to each CR vs TR entity and a normalized degree of importance for each TR is obtained. Then five pairwise comparison matrices and their priority values are obtained, based on the information of each TR among the five competitive alternative companies viz  Eicher , Tata Motors , Mahindra Navistar , Bharat Benz and Ashok Leyland. Finally, the final overall score is calculated by multiplying Priority values of each alternative with their respective TRs. The result shows that Tata LPK 2518 is the most preferable choice with the above mentioned criteria.

Key-words: Analytic hierarchy process; Quality function deployment; Off-highway vehicle

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1.  INTRODUCTION

In the present case study the authors have considered the issues related to the supply transportation system of a construction company, which deals with the construction of a dam in a hilly area.  Hence its major functionality includes the transportation of loose materials such as sand , gravel , dirt etc. in  uneven areas and country side roads . Thus selecting a particular off-highway vehicle among its competitive alternatives is a very formidable job. The selection process involves the consideration of both the customers requirement and technical requirements.

            Literature  survey  reveals  [4]  the selection of the supplier based on qualitative and quantitative factors. But the impact of the quality requirement on the integration of the customer requirements and technical requirement was ignored.

[7] proposed QFD analysis as a multi-criteria decision problem and proposed a new fuzzy outranking approach to prioritize design requirements.

None of the previously cited research work deals with the selection of a product  from a customer-requirement perspective. A new, robust methodology is adopted [1] that encompasses both the technical requirements and customer requirements for selecting a product. The present work contributes and is novel in the sense that it is easy to deal with; bulky mathematics is not required and it encompasses technical requirements as well as customer requirements .

        The adopted work outlines an integrated model combining AHP and QFD for the industrial off-highway vehicle selection problem. Computation of the degree of relative importance for customer requirements is made through AHP. Using the QFD transformation, the degrees of relative importance and normalized importance of five technical requirement are computed for constructing the product selection model. An overall score for each product model is then computed for the decision-maker to select the best product based upon multiple criteria .

The content of the paper is as follows. The next section highlights the definition and application of an off-highway vehicle followed by some of its important performance criteria. The subsequent sections discuss the adopted model and the case study using a combined AHP/QFD model.[pic 3]

2. OFF-HIGHWAY VEICHLE(DUMPER TRUCK)

An Off-highway vehicle is a truck used for transporting loose material (such as sand, gravel, or dirt). In road construction projects, there is a requirement of removal of earth all along the earmarked site till the requisite depth followed by laying of multiple layers of materials such as ‘good earth’, Granular sub base, Macadam layers and bitumen mixes. Off-highway vehicles are used for the transport of all these materials in road construction (road-site to dump and burrow or plant to road-site) .

Off-highway vehicle trucks have their numerous utility as a disposing vehicle. But for a manufacturer, there are many factors that play vital role in selecting the right Off-highway vehicle for an application. One part is based on the application  nature and significant of material to be handled, terrain, gradient, width of access roads or ‘benches’ and lead distance to be covered. On the customer side, it would depend on whether it is for captive use or for contractual work, size and duration of the contract and availability of finance. Other factors which influence choice of Off-highway vehicle could be regulatory issues and existing population of vehicles in a site. As for calculations, the relevant figures would be centered around the return a contractor would earn from his investment in a Off-highway vehicle – contract rates, contract duration, labor charges, maintenance expenses, mileage, life expectancy, depreciation and resale value.

Hence some of the performance criteria chosen for this case study are Loaded body volume(LBV),  mileage (fuel economy), price , maximum speed , Robustness , Gross vehicle weight (GVW), maximum power ,fuel tank capacity, gear box  and gradeability.

The total volume of materials that can be carried by a Off-highway vehicle at a time is called  its Loaded body volume (LBV).The LBV of a truck is generally expressed in cubic meter. The highest grade a vehicle can ascend while maintaining a particular speed is s termed that vehicle's "gradeability" . Robustness can be defined as the ability of a Off-highway vehicle to be optimally mobile on rough, slush and slippery terrain surface of uneven work sites and up and down roads of hilly and mining areas. The gross vehicle weight (GVW), is the maximum operating weight/mass of a vehicle as specified by the manufacturer including the vehicle's chassis, body, engine, engine fluids, fuel, accessories, driver, passengers and cargo. It is generally expressed in tone or Kilogram. The total number of gears including the forward, reverse and crawler are indicated in gear box . The maximum output delivered by the engine is treated as Maximum Power . it is expressed in H.P .All the performance criteria data of various companies , considered for the present case study are taken from their respective company brochures  .The price of the considered Off-highway vehicles are ex showroom price in  Delhi .

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