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Selection Of Material, Shape, And Manufacturing Process For A Connecting Rod

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2010 Annual Conference & Exposition


Louisville, Kentucky

Publication Date

June 20, 2010

Start Date

June 20, 2010

End Date

June 23, 2010



Conference Session

Materials Selection & Design

Tagged Division


Page Count


Page Numbers

15.1057.1 - 15.1057.12



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Paper Authors

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Somnath Chattopadhyay Pennsylvania State University

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NOTE: The first page of text has been automatically extracted and included below in lieu of an abstract

Selection of Material, Shape and Manufacturing Process For a Connecting Rod


This activity centers on the courses of strength of materials and production design offered at a sophomore level Mechanical Engineering curriculum. A connecting rod is one of the most mechanically stressed components in internal combustion engines. The objective of the activity is to select the appropriate material for a connecting rod where the constraints are to make the product as light and cheap as possible and yet strong enough to carry the peak load without failure in high cycle fatigue. The fracture toughness also needs to be above a certain minimum value. A further requirement is that the connecting rod should not buckle during operation. These constraints are used to select an appropriate cross section and material for construction. The next phase involves the selection of manufacturing process for which the constraints are shape, mass, quality and economics. The selections of the material, the cross-sectional shape and the manufacturing processes involve the use of CES EduPack, which yields materials that meet the constraints. The current manufacturing processes for connecting rods by fracture split drop forging and fracture split powder forging are highlighted and compared based on current information.


A connecting rod in a high performance engine is subjected to inertial forces and bearing loads. It should be able to withstand these forces for a large number of cycles. In order to reduce the forces exerted during operation, the connecting rod should weigh as little as possible and should have very high fatigue strength. The connecting rod undergoes cyclic tension, compression as well as bending. The connecting rod is subjected to a combination of axial and bending stresses. Furthermore the connecting rod is subjected to a large compressive load so that it is imperative - section is commonly used. A further consideration involves the shape of the cross-section. When a structural member is subjected to an axial tension the area of the cross-section is important but the shape is not. All sections with -section is better than a solid section of the same cross-sectional area. To characterize this, we need a metric a way of measuring the structural efficiency of a section shape, independent of the material which the connecting rod is made of. We define the shape factor of a section as the ratio of stiffness or strength of the reference shape typically a solid square cross-section with the same cross-sectional area. The material selection as influenced by the shape is outlined in this work. The selection is also based on the application of an additional standard constraint that

In order to select the proper manufacturing process, the economic, technical and quality constraints are employed. The economic constraints involve raw material cost and batch size used in production. The technical constraints consist of estimated connecting rod mass and a minimum section of the connecting rod. The quality constraints involve manufacturing tolerance

Chattopadhyay, S. (2010, June), Selection Of Material, Shape, And Manufacturing Process For A Connecting Rod Paper presented at 2010 Annual Conference & Exposition, Louisville, Kentucky. 10.18260/1-2--16217

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