Torsion Test
Chapter 10
Torsion Tests
Subjects of interest
• Introduction/Objectives • Mechanical properties in torsion • Torsional stresses for large plastic strains • Type of torsion failures • Torsion test vs.Tension test • Hot torsion testing
Suranaree University of Technology
Tapany Udomphol
May-Aug 2007
Objectives
• This chapter provides fundamental knowledge of torsion test and significant parameters such as torque, modulus of rupture in torsion and angle of rotation will be highlighted. • Different types of torsion failures will be evaluated and differentiated from tension failures.
Suranaree University of Technology
Tapany Udomphol
May-Aug 2007
Introduction
• Torsion test is not widely accepted as much as tensile test. • Torsion tests are made on materials to determine such properties as the modulus of elasticity in shear, the torsion yield strength and the modulus of rupture. • Often used for testing brittle materials and can be tested in full-sized parts, i.e., shafts, axles and twist drills which are subjected to torsional loading in service.
Suranaree University of Technology
Tapany Udomphol
May-Aug 2007
Introduction
Examples: • Driveshaft is subjected to torsion in service. www.caradvice.com GKN driveline
Bar shaft
Suranaree University of Technology
Tapany Udomphol
May-Aug 2007
Torsion-testing equipment
Torsion-testing equipment consists of 1) A twisting head, with a chuck for gripping the specimen and for applying the twisting moment to the specimen. 2) A weight head, which grips the other end of the specimen and measures the twisting moment of torque. www.echoscaninc.com Specimen used A circular cross section specimen is normally used since in the elastic range, shear stress varies linearly from a value zero at the centre of the bar to a maximum value at the surface. Note: Thin-walled tubular specimen is frequently used.
Suranaree University of Technology
Tapany Udomphol
May-Aug
Torsion Tests
Subjects of interest
• Introduction/Objectives • Mechanical properties in torsion • Torsional stresses for large plastic strains • Type of torsion failures • Torsion test vs.Tension test • Hot torsion testing
Suranaree University of Technology
Tapany Udomphol
May-Aug 2007
Objectives
• This chapter provides fundamental knowledge of torsion test and significant parameters such as torque, modulus of rupture in torsion and angle of rotation will be highlighted. • Different types of torsion failures will be evaluated and differentiated from tension failures.
Suranaree University of Technology
Tapany Udomphol
May-Aug 2007
Introduction
• Torsion test is not widely accepted as much as tensile test. • Torsion tests are made on materials to determine such properties as the modulus of elasticity in shear, the torsion yield strength and the modulus of rupture. • Often used for testing brittle materials and can be tested in full-sized parts, i.e., shafts, axles and twist drills which are subjected to torsional loading in service.
Suranaree University of Technology
Tapany Udomphol
May-Aug 2007
Introduction
Examples: • Driveshaft is subjected to torsion in service. www.caradvice.com GKN driveline
Bar shaft
Suranaree University of Technology
Tapany Udomphol
May-Aug 2007
Torsion-testing equipment
Torsion-testing equipment consists of 1) A twisting head, with a chuck for gripping the specimen and for applying the twisting moment to the specimen. 2) A weight head, which grips the other end of the specimen and measures the twisting moment of torque. www.echoscaninc.com Specimen used A circular cross section specimen is normally used since in the elastic range, shear stress varies linearly from a value zero at the centre of the bar to a maximum value at the surface. Note: Thin-walled tubular specimen is frequently used.
Suranaree University of Technology
Tapany Udomphol
May-Aug
References: • Dieter, G.E., Mechanical metallurgy, 1988, SI metric edition, McGraw-Hill, ISBN 0-07-100406-8. Suranaree University of Technology Tapany Udomphol May-Aug 2007