Abstract III
Zusammenfassung V

1 Introduction  1
1.1 Motivation  2
1.2 Thesis Structure  5
1.3 High-Speed Imaging  6
1.3.1 Modern High-Speed Imaging  7
1.3.2 Categorization and Market Survey  8
1.4 Surface Measurements  10
1.4.1 Camera System Calibration  10
1.4.2 Digital Image Correlation  11
1.4.3 Surface Reconstruction and Material Property Derivation  12

2 Foundations, Methods, and RelatedWork  15
2.1 Accuracy Potential of High-Speed Measurements  15
2.1.1 Absolute Accuracy  17
2.1.1.1 Review of Measurement Validation  17
2.1.1.2 Review of Conventional Devices  17
2.1.1.3 Tailored Setup for High-Impact Validation  18
2.1.1.4 Concluding Remarks   20
2.1.2 Internal Accuracy  20
2.1.3 Relative Accuracy  22
2.1.4 Practical Use Case  23
2.2 High-Speed Imaging in Impact Loading Applications  25
2.2.1 Digital Image Correlation in Impact Applications  26
2.2.2 Broader Use of High-Speed Imaging Techniques  27
2.2.3 Technical Evaluation of High-Speed Imaging Acquisition  28
2.2.3.1 Camera Triggering  28
2.2.3.2 Sensor Operation Characteristics Influencing Image Quality  30
2.2.3.3 Performance of High-Speed Imaging Systems Using Various Sensor
Technologies  31
2.3 Exploring Ultrahigh-Speed Imaging for Dynamic Material Analysis  34
2.3.1 Temporal Capture of Deformation Stages  34
2.3.2 Potential of Spatio-Temporal Image Filtering Techniques  35
2.3.3 From Ultrahigh-Speed Imaging to Longitudinal Wave Velocity Estimation  38

3 Analyzing the Accuracy Potential of 3D High-Speed Camera Measurements  39
3.0 Abstract  40
3.1 Introduction  40
3.1.1 General Background  40
3.1.2 Research Problem Analysis  41
3.1.3 Structure  42
3.2 Experimental Setup  42
3.3 Methodology  45
3.3.1 Rigid-Body Transformation  47
3.3.2 Relative Measurements Analysis  48
3.4 Experimental Results  49
3.4.1 Rigid-Body Transformations  49
3.4.2 Relative 3D Measurements  54
3.4.2.1 Temporal Measurement Stability  55
3.4.2.2 Geometrical Measurement Stability  56
3.5 Discussion  58
3.6 Conclusions  59
3.7 Appendix A. Influence of Camera Calibration on Static Measurements  61
3.8 Appendix B. Image Performance of Static and Dynamic Recordings  62
3.9 References  65

4 Ultrahigh-speed Imaging for High-Impact Concrete Deformation Analysis 67
4.0 Abstract  68
4.1 Introduction  68
4.1.1 State of the Art  69
4.2 Experimental Setups  70
4.3 Camera Characterization  71
4.3.1 Sensor Operation  71
4.3.2 Image Acquisition Challenges  73
4.3.2.1 Recording Capacity  73
4.3.2.2 Sensor Sensitivity  73
4.3.2.3 Image Lag  74
4.3.2.4 Fixed Pattern Noise  75
4.4 High-Impact Load Applications  76
4.4.1 Surface Particle Propagation  76
4.4.2 Crack Propagation Velocity  79
4.5 Discussion  81
4.6 Conclusions and Outlook  82
4.7 References  82

5 LongitudinalWave Propagation Velocity and Longitudinal Deformations in Concrete 
 85
5.0 Abstract  86
5.1 Introduction  87
5.1.1 High-frequency measuring devices  87
5.1.2 Impact-induced wave propagation  88
5.1.3 Techniques goals and structure of the work  89
5.2 One-dimensional wave theory  89
5.3 Experimental setup  90
5.3.1 Ultrahigh-speed optical measurements  91
5.3.2 Strain gauge measurements  92
5.3.3 Test configuration  92
5.4 Methodology  93
5.4.1 Direct material analysis  93
5.4.1.1 Image-sequence-based evaluation  94
5.4.1.2 Bézier image fitting filtering  94
5.4.1.3 Selection of stress-wave-induced motion points  96
5.4.2 Indirect material analysis  97
5.4.2.1 Strain gauge evaluation  97
5.4.2.2 Velocity and deformation  98
5.4.2.3 Strain strain Rate and strain Acceleration  98
5.4.2.4 Stress and its corrections  98
5.4.2.5 Incident energy  99
5.5 Validation of the results  99
5.5.1 Longitudinal wave propagation velocity  99
5.5.1.1 Base wave propagation velocities  99
5.5.1.2 Corrected wave propagation velocities  102
5.5.1.3 Wave amplitude  103
5.5.2 Accordance of direct and indirect material analysis  103
5.5.2.1 Bilateral complementarity  103
5.5.2.2 Correlations and discrepancies  104
5.6 Discussion  106
5.6.1 Direct measurement of the specimen deformation  106
5.6.2 Determination of the longitudinal wave propagation velocity in concrete  106
5.6.3 Assessment of measuring techniques for material analysis  107
5.7 Conclusion and outlook  108
5.8 References  109

6 Synthesis 111
6.1 Performance Analysis of High-Speed Imaging Systems  111
6.2 Evaluation of Ultrahigh-Speed Image Sequences  113
6.3 Determination and Validation of Longitudinal Wave Propagation Velocity and Induced Deformations  115
6.4 Conclusions  117
6.5 Outlook  118
6.5.1 Measuring Potential of Ultrahigh-Speed Measurements  118
6.5.2 Increasing Image Filtering Performance  119
6.5.3 Enhanced Longitudinal Wave Propagation Analysis  120
6.5.4 Longitudinal Wave Propagation Analysis in Large-Scale Concrete Structures  120
6.5.5 Surface and Transverse Wave Propagation Analysis  121
6.5.6 Concluding Outlook  122

References 123

List of Tables 129
List of Figures 131
List of Abbreviations 133