Prof. Dr.-Ing. Stefan Keil played an authoritative part in the development of modern experimental strain analysis. Stefan Keil was born in 1937. He studied mechanical engineering at RWTH Aachen, Germany. After graduation he researched on strength of materials and leaded fatigue tests on structural components of aircrafts with Hamburger Flugzeugbau GmbH. He then returned to the RWTH Aachen Institute of Material Science as assistant professor where he was active in research on material behavior under service loads. He dealt with strength calculations and methods of stress analysis using strain gages, i.e. in the elastoplastic deformation range. He received his doctorate in 1970 and was honored with the Borchers Award. From 1971 to 1996 he was employed with Hottinger Baldwin Messtechnik where he spezialized in the technique and application of strain gages. Here he was responsible for research projects dealing with the experimental assessment of load-bearing capacity and safety of structures. From 1996 to 1999 Stefan Keil has worked with the Institute of Experimental Statics in Bremen. In 1997 he was appointed associate lecturer and honorary professor in 2003 at the Technical University of Clausthal. For more than 20 years he was the editor of the journal ?Messtechnische Briefe? and in 1985 he founded the journal ?Reports in Applied Measurement? RAM. He is member of the GESA executive board and in 2010 he was awarded the VDI honorary plaque. He has authored and co-authored more than 60 journal papers, a large number of conference papers, and has been a working member of several technical committees and working groups. Stefan Keil is a sought-after expert advisor in the field of experimental mechanics.

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• 1 Historical Review2 Fundamentals of strain gage technology2.1 Measurement principle and structure2.2 Sensitivity2.3 Transverse sensitivity2.4 Temperature effect2.5 Mechanics of the strain gage2.6 Influence of pressure2.7 Dynamic behavior2.8 Heat dissipation2.9 Measuring at elevated temperatures2.10 Stress gages3 Installation of strain gages3.1 Preparatory work3.2 Methods of fastening3.3 Remarks on some measurement object materials (Glas, enamel, glaced porcelain, Concrete, Wood, Plastics)3.4 Measurement point protection3.5 Quality tests of the strain gage installation4 The Wheatstone bridge circuit4.1 Circuit principle4.2 Basic equation of the bridge circuit4.3 Temperature compensation4.4 Limit of the bridge signal resolution4.5 Examples of some elementary bridge circuits5 Adjustment and compensation circuits5.1 General5.2 Compensation of zero shift with temperature change and zero adjustment5.3 Compensation of temperature effects on the sensitivity and linearization measures5.4 Adjustment of the characteristic value5.5 Creep compensation5.6 Full bridge circuits connected in parallel6 Cable between strain gage bridge circuit and measuring instrument6.1 Basics6.2 Ohmic resistance of the cable6.3 Influence of cable capacitance6.4 Full-bridge connection in four-wire technology6.5 Six-wire circuit6.6 Dual channel principle6.7 Connection of half and quarter bridges6.8 Protection against disturbing influences7 Signal processing7.1 Introductory viewing7.2 Analog instrumentation amplifier7.3 Digital amplifier concepts7.4 Compensation method7.5 Multi-point Measurement8 Calibration devices for measurements with strain gages8.1 Introduction8.2 Measurement chain8.3 Characteristic and sensitivity8.4 Calibration of the entire measuring chain as a measuring device8.5 Compensators8.6 Transducers8.7 Calibration measures8.8 Calibration of measuring arrangements with self-installed strain gages9 Determination of mechanical stresses from strains measured with strain gages9.1 Introduction9.2 Terms of stress and strain9.3 Elastic deformation and stress of a tensile rod under uniaxial tensile loading9.4 The biaxial stress state9.5 Mohr?s Circle9.6 Deformation circle9.7 Types of rosettes and grid notation9.8 Evaluation formulas for 0°/45°/90° strain-gage rosettes9.9 Evaluation formulas for 0°/60°/120° strain-gage rosettes10 Application examples of elastic deformation10.1 Initial considerations10.2 Principal directions are known10.3 Stress analysis for unknown principal directions10.4 Simultaneous measurement of multiple load components10.5 Diaphragm rosettes11 Determination of thermal stresses11.1 Emergence of thermal stresses11.2 Sensing the prevented thermal expansion at identical temperatures at the compensation gage and the active strain gage11.3 Determination of the restricted thermal expansion by computational correction of the measured values with previously measured thermal outputs on dummies11.4 Determination of the restricted thermal expansion by mathematical correction with the thermal outputs determined at the original measurement object11.5 The ?reversible? strain gage11.6 Separation of the mechanical strain from the thermal strain11.7 Compensated half-bridge strain gage with compensating resistor12 Strain gages as a means for experimental determination of residual stresses12.1 Preliminary observation12.2 Cutting down method12.3 Layer removal method12.4 Ring-core method12.5 Hole-drilling method13 Stress analysis using strain gages in the elasto-plastic deformation range13.1 Introduction13.2 Equivalent state with elastic deformation13.3 Elasto-plastic deformation13.4 Stress analysis13.5 Practical Example of application13.6 Tensorial representation of the elasto-plastic deformation14 Strength theories14.1 Preview14.2 Concept of effective stress14.3 Experimental results14.4 Maximum stress theory14.5 Maximum shear theory14.6 Extended shear theory14.7 Plastic potential theory14.8 Distortion energy theory (shape changing theory)14.9 Octahedral plane shear stress theoryReferencesSubject Index

Prof. Dr.-Ing. Stefan Keil played an authoritative part in the development of modern experimental strain analysis. Stefan Keil was born in 1937. He studied mechanical engineering at RWTH Aachen, Germany. After graduation he researched on strength of materials and leaded fatigue tests on structural components of aircrafts with Hamburger Flugzeugbau GmbH. He then returned to the RWTH Aachen Institute of Material Science as assistant professor where he was active in research on material behavior under service loads. He dealt with strength calculations and methods of stress analysis using strain gages, i.e. in the elastoplastic deformation range. He received his doctorate in 1970 and was honored with the Borchers Award. From 1971 to 1996 he was employed with Hottinger Baldwin Messtechnik where he spezialized in the technique and application of strain gages. Here he was responsible for research projects dealing with the experimental assessment of load-bearing capacity and safety of structures. From 1996 to 1999 Stefan Keil has worked with the Institute of Experimental Statics in Bremen. In 1997 he was appointed associate lecturer and honorary professor in 2003 at the Technical University of Clausthal. For more than 20 years he was the editor of the journal ?Messtechnische Briefe? and in 1985 he founded the journal ?Reports in Applied Measurement? RAM. He is member of the GESA executive board and in 2010 he was awarded the VDI honorary plaque. He has authored and co-authored more than 60 journal papers, a large number of conference papers, and has been a working member of several technical committees and working groups. Stefan Keil is a sought-after expert advisor in the field of experimental mechanics.

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• 1 Historical Review2 Fundamentals of strain gage technology2.1 Measurement principle and structure2.2 Sensitivity2.3 Transverse sensitivity2.4 Temperature effect2.5 Mechanics of the strain gage2.6 Influence of pressure2.7 Dynamic behavior2.8 Heat dissipation2.9 Measuring at elevated temperatures2.10 Stress gages3 Installation of strain gages3.1 Preparatory work3.2 Methods of fastening3.3 Remarks on some measurement object materials (Glas, enamel, glaced porcelain, Concrete, Wood, Plastics)3.4 Measurement point protection3.5 Quality tests of the strain gage installation4 The Wheatstone bridge circuit4.1 Circuit principle4.2 Basic equation of the bridge circuit4.3 Temperature compensation4.4 Limit of the bridge signal resolution4.5 Examples of some elementary bridge circuits5 Adjustment and compensation circuits5.1 General5.2 Compensation of zero shift with temperature change and zero adjustment5.3 Compensation of temperature effects on the sensitivity and linearization measures5.4 Adjustment of the characteristic value5.5 Creep compensation5.6 Full bridge circuits connected in parallel6 Cable between strain gage bridge circuit and measuring instrument6.1 Basics6.2 Ohmic resistance of the cable6.3 Influence of cable capacitance6.4 Full-bridge connection in four-wire technology6.5 Six-wire circuit6.6 Dual channel principle6.7 Connection of half and quarter bridges6.8 Protection against disturbing influences7 Signal processing7.1 Introductory viewing7.2 Analog instrumentation amplifier7.3 Digital amplifier concepts7.4 Compensation method7.5 Multi-point Measurement8 Calibration devices for measurements with strain gages8.1 Introduction8.2 Measurement chain8.3 Characteristic and sensitivity8.4 Calibration of the entire measuring chain as a measuring device8.5 Compensators8.6 Transducers8.7 Calibration measures8.8 Calibration of measuring arrangements with self-installed strain gages9 Determination of mechanical stresses from strains measured with strain gages9.1 Introduction9.2 Terms of stress and strain9.3 Elastic deformation and stress of a tensile rod under uniaxial tensile loading9.4 The biaxial stress state9.5 Mohr?s Circle9.6 Deformation circle9.7 Types of rosettes and grid notation9.8 Evaluation formulas for 0°/45°/90° strain-gage rosettes9.9 Evaluation formulas for 0°/60°/120° strain-gage rosettes10 Application examples of elastic deformation10.1 Initial considerations10.2 Principal directions are known10.3 Stress analysis for unknown principal directions10.4 Simultaneous measurement of multiple load components10.5 Diaphragm rosettes11 Determination of thermal stresses11.1 Emergence of thermal stresses11.2 Sensing the prevented thermal expansion at identical temperatures at the compensation gage and the active strain gage11.3 Determination of the restricted thermal expansion by computational correction of the measured values with previously measured thermal outputs on dummies11.4 Determination of the restricted thermal expansion by mathematical correction with the thermal outputs determined at the original measurement object11.5 The ?reversible? strain gage11.6 Separation of the mechanical strain from the thermal strain11.7 Compensated half-bridge strain gage with compensating resistor12 Strain gages as a means for experimental determination of residual stresses12.1 Preliminary observation12.2 Cutting down method12.3 Layer removal method12.4 Ring-core method12.5 Hole-drilling method13 Stress analysis using strain gages in the elasto-plastic deformation range13.1 Introduction13.2 Equivalent state with elastic deformation13.3 Elasto-plastic deformation13.4 Stress analysis13.5 Practical Example of application13.6 Tensorial representation of the elasto-plastic deformation14 Strength theories14.1 Preview14.2 Concept of effective stress14.3 Experimental results14.4 Maximum stress theory14.5 Maximum shear theory14.6 Extended shear theory14.7 Plastic potential theory14.8 Distortion energy theory (shape changing theory)14.9 Octahedral plane shear stress theoryReferencesSubject Index

Prof. Dr.-Ing. Stefan Keil played an authoritative part in the development of modern experimental strain analysis. Stefan Keil was born in 1937. He studied mechanical engineering at RWTH Aachen, Germany. After graduation he researched on strength of materials and leaded fatigue tests on structural components of aircrafts with Hamburger Flugzeugbau GmbH. He then returned to the RWTH Aachen Institute of Material Science as assistant professor where he was active in research on material behavior under service loads. He dealt with strength calculations and methods of stress analysis using strain gages, i.e. in the elastoplastic deformation range. He received his doctorate in 1970 and was honored with the Borchers Award. From 1971 to 1996 he was employed with Hottinger Baldwin Messtechnik where he spezialized in the technique and application of strain gages. Here he was responsible for research projects dealing with the experimental assessment of load-bearing capacity and safety of structures. From 1996 to 1999 Stefan Keil has worked with the Institute of Experimental Statics in Bremen. In 1997 he was appointed associate lecturer and honorary professor in 2003 at the Technical University of Clausthal. For more than 20 years he was the editor of the journal ?Messtechnische Briefe? and in 1985 he founded the journal ?Reports in Applied Measurement? RAM. He is member of the GESA executive board and in 2010 he was awarded the VDI honorary plaque. He has authored and co-authored more than 60 journal papers, a large number of conference papers, and has been a working member of several technical committees and working groups. Stefan Keil is a sought-after expert advisor in the field of experimental mechanics.

Select Guide Rating

• 1 Historical Review2 Fundamentals of strain gage technology2.1 Measurement principle and structure2.2 Sensitivity2.3 Transverse sensitivity2.4 Temperature effect2.5 Mechanics of the strain gage2.6 Influence of pressure2.7 Dynamic behavior2.8 Heat dissipation2.9 Measuring at elevated temperatures2.10 Stress gages3 Installation of strain gages3.1 Preparatory work3.2 Methods of fastening3.3 Remarks on some measurement object materials (Glas, enamel, glaced porcelain, Concrete, Wood, Plastics)3.4 Measurement point protection3.5 Quality tests of the strain gage installation4 The Wheatstone bridge circuit4.1 Circuit principle4.2 Basic equation of the bridge circuit4.3 Temperature compensation4.4 Limit of the bridge signal resolution4.5 Examples of some elementary bridge circuits5 Adjustment and compensation circuits5.1 General5.2 Compensation of zero shift with temperature change and zero adjustment5.3 Compensation of temperature effects on the sensitivity and linearization measures5.4 Adjustment of the characteristic value5.5 Creep compensation5.6 Full bridge circuits connected in parallel6 Cable between strain gage bridge circuit and measuring instrument6.1 Basics6.2 Ohmic resistance of the cable6.3 Influence of cable capacitance6.4 Full-bridge connection in four-wire technology6.5 Six-wire circuit6.6 Dual channel principle6.7 Connection of half and quarter bridges6.8 Protection against disturbing influences7 Signal processing7.1 Introductory viewing7.2 Analog instrumentation amplifier7.3 Digital amplifier concepts7.4 Compensation method7.5 Multi-point Measurement8 Calibration devices for measurements with strain gages8.1 Introduction8.2 Measurement chain8.3 Characteristic and sensitivity8.4 Calibration of the entire measuring chain as a measuring device8.5 Compensators8.6 Transducers8.7 Calibration measures8.8 Calibration of measuring arrangements with self-installed strain gages9 Determination of mechanical stresses from strains measured with strain gages9.1 Introduction9.2 Terms of stress and strain9.3 Elastic deformation and stress of a tensile rod under uniaxial tensile loading9.4 The biaxial stress state9.5 Mohr?s Circle9.6 Deformation circle9.7 Types of rosettes and grid notation9.8 Evaluation formulas for 0°/45°/90° strain-gage rosettes9.9 Evaluation formulas for 0°/60°/120° strain-gage rosettes10 Application examples of elastic deformation10.1 Initial considerations10.2 Principal directions are known10.3 Stress analysis for unknown principal directions10.4 Simultaneous measurement of multiple load components10.5 Diaphragm rosettes11 Determination of thermal stresses11.1 Emergence of thermal stresses11.2 Sensing the prevented thermal expansion at identical temperatures at the compensation gage and the active strain gage11.3 Determination of the restricted thermal expansion by computational correction of the measured values with previously measured thermal outputs on dummies11.4 Determination of the restricted thermal expansion by mathematical correction with the thermal outputs determined at the original measurement object11.5 The ?reversible? strain gage11.6 Separation of the mechanical strain from the thermal strain11.7 Compensated half-bridge strain gage with compensating resistor12 Strain gages as a means for experimental determination of residual stresses12.1 Preliminary observation12.2 Cutting down method12.3 Layer removal method12.4 Ring-core method12.5 Hole-drilling method13 Stress analysis using strain gages in the elasto-plastic deformation range13.1 Introduction13.2 Equivalent state with elastic deformation13.3 Elasto-plastic deformation13.4 Stress analysis13.5 Practical Example of application13.6 Tensorial representation of the elasto-plastic deformation14 Strength theories14.1 Preview14.2 Concept of effective stress14.3 Experimental results14.4 Maximum stress theory14.5 Maximum shear theory14.6 Extended shear theory14.7 Plastic potential theory14.8 Distortion energy theory (shape changing theory)14.9 Octahedral plane shear stress theoryReferencesSubject Index