After September 11, 2001, government officials and the engineering community have devoted significant time and resources to protect the country from such attacks again. Because highway infrastructure plays such a critical role in the public’s daily life, research has been conducted to determine the resiliency of various bridge components subjected to blast loads. While more tests are needed, it is now time to transfer the research into tools to be used by the design community. The development of Anti-Terrorism Planner for Bridges (ATP-Bridge), a program intended to be used by bridge engineers and planners to investigate blast loads against bridges, is explained in this thesis. The overall project goal was to build a program that can incorporate multiple bridge components while still maintaining a simple, user-friendly interface. This goal was achieved by balancing three core areas: constraining the graphical user interface (GUI) to similar themes across the program, allowing flexibility in the creation of the numerical models, and designing the data structures using object-oriented programming concepts to connect the GUI with the numerical models. An example of a solver (prestressed girder with advanced SDOF analysis model) is also presented to illustrate a fast-running algorithm. The SDOF model incorporates the development of a moment-curvature response curve created by a layer-by-layer analysis, a non-linear static analysis accounting for both geometric non-linearity as well as material non-linearity, and a Newmark-beta-based SDOF analysis. The results of the model return the dynamic response history and the amount of damage. ATP-Bridge is the first software developed that incorporates multiple bridge components into one user-friendly engineering tool for protecting bridge structures against terrorist threats. The software is intended to serve as a synthesis of state-of-the-art knowledge, with future updates made to the program as more research becomes available. In contrast to physical testing and high-fidelity finite element simulations, ATP-Bridge uses less time-consuming, more cost effective numerical models to generate dynamic response data and damage estimates. With this tool, engineers and planners will be able to safeguard the nation’s bridge inventory and, in turn, reinforce the public’s trust. / text

This thesis focuses on the dynamic and static behaviour of reinforced concrete beams built using high-strength concrete and high-strength steel reinforcement. As part of this study, a total of 8 high-strength concrete beams, built with and without steel fibres, and reinforced with high strength ASTM A1035 bars are tested under simulated blast loading using the University of Ottawa shock-tube, with an additional 3 companion beams tested under quasi-static loading. The variables considered in this study include: concrete type, fibre content, steel reinforcement ratio and steel reinforcement type. The behaviour of the beams with high-strength steel bars is compared to a companion set of beams reinforced with conventional steel reinforcement. The criteria used to evaluate the blast performance of the beams includes: overall blast capacity, maximum and residual displacements, secondary fragmentation and crack control. The dynamic results show that high strength concrete beams reinforced with high-strength steel are able to resist higher blast loads and reduce displacements when compared to companion beams with conventional steel reinforcement. The results also demonstrate that the addition of steel fibres is effective in controlling crack formation, minimizing secondary blast fragments, reducing displacements and further increasing overall blast capacity. However, the use of high-strength steel and high-strength concrete also shows potential for brittle failures under extreme blast pressures. The static results show that specimens with high-strength steel bars do not increase beam stiffness, but significantly increase peak load carrying capacity when compared to beams with the same ratio of conventional steel reinforcement. The analytical research program aims at predicting the response of the test beams using dynamic inelastic single-degree-of-freedom (SDOF) analysis and includes a sensitivity analysis examining the effect of various modelling parameters on the response predictions. Overall the analytical results demonstrate that SDOF analysis can be used to predict the blast response of beams built with high-strength concrete and steel reinforcement with acceptable accuracy.

This student thesis aims to analyze the unbalance on rotating machinery by simulation and experimental. The machinery flywheel rotation is modelled as a Single Degree of Freedom (SDOF) and Multi Degree of Freedom (MDOF) system. The model rotation unbalance is simulated by MATLAB. Then the vibration measurement is taken by experimental. In addition, the tachometer is used to determine the flywheel speed calibration. Finally, the rotating unbalance reduction simulation is performed with different parameter value to determine an optimum level of machinery rotation vibration. Unbalance on rotating machinery causes a harmful influence on the environment and machinery. The root cause of rotating unbalance is determined by the simulation and experimental analysis. The analysis result is used as an indicator for predicting machinery breakdown and estimating the correct predictive maintenance action for the machinery. In this project, the simulation and experimental analysis were carried out on a rotating component of the KICKR Snap Bike Trainer. The simulation and numerical analysis are performed by MATLAB programme. On the experimental part, the vibration measurement method and results were discussed. The suggestion of unbalance reduction were recommended base on measurement and vibration analysis results.

Heavy crushing machines under their production shifts, creates various levels of vibration, noise and dynamic forces which can be transferred to other parts of the industrial unit. Such kind of factors applies continuous forces on machine parts which can cause gradual fatigue, creep and eventually failure of machine. In this thesis work we are studying Jaw crusher machine from Sandvik company, since the company has a high focus on safety and quality, this thesis is aiming to estimate the dynamic foundation loads that are transmitted to substructure of the jaw crusher. The thesis is based on estimating power spectral density transmissibility matrix-single value decomposition (PSDTM-SVD), between jaw crusher foot (CRF), side wall (SW) and substructure (SS) in x, y, z positions to identify model parameters including damped eigenfrequencies and mode shapes. This research has concluded that it is possible to estimate the transmitted load force by finding the relation between displacement transmissibility and force transmissibility by employing (PSDTM-SVD) method. In fact (PSDTM-SVD) is a sufficient method to estimate the damped eigenfrequencies and mode shapes during operation.  Nevertheless, it is majorly important to have good coherence between measured data, in this case data that have been conducted in Y direction had a good coherence of 0.9.

<p>The increased public safety concerns to the consequences of deliberate and accidental explosions have led to the development of the Canadian (CSA S850- 12) and American (ASCE 59-11) blast standards. There is an urgent need to investigate and quantify the response of structural components under such extreme loading conditions. This is especially important for masonry components, where research has been limited due to the misconception that masonry (both reinforced and unreinforced) is an inadequate material for blast hardening applications. The standards allow the use of experimental testing or dynamic analysis in order to determine peak responses and evaluate them in terms of the code prescribed performance limits and accompanying levels of damage. The current study investigates the response of non-integral and non-participating infill walls designed to undergo two-way out-of-plane response and detailed to fail in flexure under static loading conditions. Through experimental blast testing and dynamic model validation of reduced-scale walls under a range of design-basis threat (DBT) levels, this study shows that reinforced masonry is a viable alternative for blast protection. However, the current flexural-based code requirements, thought to be conservative, may be inadequate at loads of higher impulse where shear damage is prevalent. This study also shows the influence that changing the boundary configuration and level of reinforcement has on the peak response, where the performance limits of the current codes makes no provisions for these parameters.</p> / Master of Applied Science (MASc)

The threat of terrorist bombings and accidental industrial explosions motivates the need for more economical and efficient blast-resistant construction techniques that offer enhanced levels of protection at reduced component damage levels. Despite having a high strength-to-weight ratio and being chemically inert, fiber reinforced polymer (FRP) reinforcing bars are not currently used in blast-resistant reinforced concrete due to their brittle nature and lack of ductility. However, the innovative use of blended mixtures of FRP and steel rebar as tensile reinforcement promises to address these limitations through self-centering behavior that provides reductions in residual damage and enhancements in flexural performance. This thesis presents the results of an experimental and analytical investigation on the effect of hybrid arrangements of glass fiber reinforced polymer (GFRP) and conventional mild steel reinforcement on the blast performance of reinforced concrete beams. Seven large-scale reinforced concrete beams with different combinations of tensile steel and GFRP rebar were designed, constructed, and tested under progressively increasing blast loading generated using the Virginia Tech Shock Tube Research Facility. The effect of hybrid reinforcing on the blast performance of the beams was evaluated based on the global response, failure mode, damage pattern, mid-span displacement, and support reactions of the tested beams. The results demonstrated several benefits in using hybrid arrangements of steel and GFRP reinforcement. Beams with hybrid reinforcing experienced reduced overall residual displacements compared with similar conventionally reinforced concrete members. This was attributed to the elastic nature of GFRP rebar which was found to produce a self-centering behavior that assisted in returning the hybrid members to their original undeformed position. This permitted the hybrid beams to safely experience larger maximum displacements at substantially less damage than all-steel construction. Furthermore, if the GFRP reinforcement did rupture, the presence of steel arrested hazardous component failure and provided additional energy dissipation and redundancy. Accompanying the experimental tests was an inelastic single-degree-of-freedom analysis to predict the displacement time-history response of the beams. Reasonably good predictions of response were obtained when the advanced material models and the effects of accumulated damage due to repeated blast testing were incorporated into the analytical predictions. Finally, a series of protective design recommendations and a new proposed response limit, that describes the level of damage achieved after a blast event, were established to encourage use of hybrid GFRP/steel reinforcement in blast-resistant construction. / Master of Science / The threat of terrorist bombings and accidental industrial explosions motivate the need for new blast resistant construction techniques. Despite having a high strength-to-weight ratio and being chemically inert, fiber reinforced polymer (FRP) reinforcing bars are not currently used in blast-resistant reinforced concrete due to their brittle nature and lack of ductility. However, the innovative use of blended mixtures of FRP and steel rebar as tensile reinforcement promises to address these limitations through self-centering behavior that provides reductions in residual damage and enhancements in flexural performance. Large-scale reinforced concrete beams with different combinations of steel and GFRP rebar were designed, constructed, and tested under progressively increasing blast loads, gen-erated by the Virginia Tech Shock Tube Research Facility. The results demonstrated that beams with hybrid reinforcing experienced reduced overall residual damage in comparison with similar conventionally reinforced concrete members. Additionally, if the GFRP rebar ruptured, the presence of steel prevented a brittle failure and provided additional energy dissipation and redundancy. The inelastic single degree of freedom model developed for this investigation resulted in an adequate prediction of the load-deflection characteristics record-ed from experimental testing. To encourage the use of hybrid FRP/steel reinforcement in blast-resistant construction, a series of protective design recommendations and a proposed response limit, that describes the level of damage achieved after a given blast event, were established.

Accounting for blast hazards has become one of the major concerns for civil engineers when analysing and designing structures. Recent terrorist attacks and accidental explosions have demonstrated the importance of mitigating blast effects on buildings to ensure safety, preserve life and ensure structural integrity. Innovative materials such as high-strength concrete, steel fibers, and high-strength steel offer a potential solution to increase resistance against extreme dynamic loading and improve the blast resilience of buildings. This thesis presents the results of an experimental and analytical study examining the effect of high-strength concrete, high-strength reinforcement and steel fibers on the blast behaviour of reinforced concrete columns. As part of the study, a total of seventeen reinforced concrete columns with different design combinations of concrete, steel fibers, and steel reinforcement were designed, constructed, and tested under gradually increasing blast loads using the University of Ottawa shock-tube facility. Criteria used to assess the blast performance of the columns and the effect of the test variables included overall blast capacity, mid-span displacements, cracking patterns, secondary fragmentation, and failure modes. The effect of concrete strength was found to only have a moderate effect on the blast performance of the columns. However, the results showed that benefits are associated with the combined use of high-strength concrete with steel fibers and high-strength reinforcement in columns tested under blast loads. In addition to the experimental program, a dynamic inelastic single-degree-of-freedom analysis was performed to predict the displacement response of the test columns. A sensitivity analysis was also conducted to examine the effect of various modelling parameters such as materials models, DIFs, and accumulated damage on the analytical predictions.

A need for a cost effective, versatile and easy to use suspension component testing method has arisen, following the development of a four-state hydro-pneumatic semi-active spring-damper system. A method known as hardware-in-the-loop (HiL) was investigated, in particular its use and compatibility with tests involving physical systems – previously HiL was used predominantly for Electronic Control Unit (ECU) testing. The suitability of HiL in the development of advanced suspension systems and their control systems, during which various vehicle models can be used, was determined. A first step in vehicle suspension design is estimating a desired spring and damper characteristic, and verifying that characteristic using software simulation. The models used during this step are usually low-order, simple models, which hampers quick development progress. To predict vehicle response before vehicle prototype completion, many researchers have attempted to use complex and advanced damper models to simulate the vehicle’s dynamics, but these models all suffer from some drawback – it is either based on empirical data, giving no indication of the physical parameters of the design sought; it may be overly complex, having many parameters and thus rendering software impractical; or it may be quick but based on the premise that there is no hysteresis in the damping character. It can be seen that an obvious answer exists – use a physical commercially available or prototype damper in the software simulation instead of the mathematical model. In this way the suspension deflection, i.e. the true motion of the damper is used as excitation, and the true damper force is measured using a hydraulic actuator and load cell. The vehicle mass motions are simulated in a software environment. This is basically what HiL simulation does. The HiL method was verified by comparing HiL simulations and tests to globally accepted testing methods, employing widely-used vehicle models: linear single-degree-of-freedom (SDOF) and two-degrees-of-freedom (2DOF) or quarter-car models were used. The HiL method was also compared to a non-linear physical system to verify that the method holds for real vehicle suspension geometries. This meant that HiL had to perform adequately at both ends of the suspension-testing spectrum – base software and real system simulation. The comparison of the HiL and software/real system simulation was done using the “Error Coefficient of Variance” (ECOV) between the compared signals; this quantitative measure proved very sensitive and performed dubiously in the presence of signal offsets, phase lags and scaling errors, but remains a tangible, measurable parameter with which to compare signals. Visual confirmation was also obtained to back the ECOV values. It was found that even using a relatively low-force actuator, the HiL simulation results followed the software/real system responses well. Phase lags and DC offsets in the HiL simulation’s measured signals (as well as the real systems responses) has an adverse effect on the performance of the HiL simulation. Special attention must thus be paid to the zeroing of equipment and the amount/type of filters in the system, as these affect the HiL results dramatically. In all, HiL was proven to be a versatile and easy to use alternative to conventional mass-based suspension testing. / Dissertation (MEng (Mechanical Engineering))--University of Pretoria, 2006. / Mechanical and Aeronautical Engineering / unrestricted

The CSA S850 Blast standard provides guidelines that can be used to enhance the blast performance of reinforced concrete structures. In the case of beams, the standard requires the use of top continuity (compression) bars and well-detailed transverse steel to ensure strength and ductility under blast loads. However, the requirements in the CSA S850 standard are intended for normal-strength concrete structures. Given the increased use of high-strength concrete (HSC) in practice, there is a need to explore the effects of modern blast designs on the behavior of HSC structures subjected to blast loads. Accordingly, this project examines the effect of modern reinforcement detailing on the static, dynamic and post-blast performance of high-strength concrete beams. The study further examines the ability to use fibers to relax such detailing and simplify construction. A total of seventeen beams are tested. Static testing is conducted under four-point bending, with blast testing conducted using the University of Ottawa shock-tube. The post-blast behavior of the beams is assessed by conducting residual static tests on the blast-damaged specimens. The parameters investigated include the effects of: blast detailing vs. nominal detailing, steel fibers, the effect of longitudinal steel ratio (in compression and tension) and tie spacing. The results show that under static loads, the use of blast detailing significantly improves the flexural behavior of the beams in terms of ductility. Likewise, the provision of continuity (compression) bars and closely spaced ties is found to improve blast performance by better controlling displacements, increasing blast resistance, limiting damages and allowing for important post-blast residual capacity. The use of steel fibers and relaxed detailing (increased tie spacing) is found to increase resistance and improve cracking behavior under static loads, with an ability to match the blast performance of more heavily-detailed HSC specimens. The use of fibers also allowed for substantial post-blast capacity. Finally, the steel ratio (in tension, in compression and in the transverse direction) was found to affect the blast behavior of the HSC beams. In addition to the experiments, the analytical study predicts the static and blast response of the tested beams using sectional analysis and non-linear SDOF modeling. Results show that the analysis methodology was able to predict the static and blast responses of the blast-detailed and fiber-reinforced HSC beams with reasonable accuracy.

In this thesis, the dynamic structural response of six scaled flexural masonry walls to scaled blast loading is experimentally investigated. These walls have been tested in at an open range with charge masses ranging from 5 kg to 25 kg of Pentex-D explosive material with a TNT equivalency of 1.2, and with a constant stand-off distance of 5 m throughout testing. The field properties of the blast wave, which includes the reflected and free field pressures, were recorded. Additionally, the displacement response histories of the wall over the blast test were recorded and the post-blast damage was documented. This study puts forth several potential models for the analysis of the experimental data. The experimentally obtained blast characteristics were compared to predictions of the Kingery and Bulmash (K-B) model. The strain rates used during the study are equivalent to those developed by a number of studies for the materials used in the construction of the specimens. The results obtained through the experimental program are compared to those from a variety of single degree of freedom models, ranging from simplified linear relationships to complex stress-strain relations accounting for the effects that arise because of the increased strain rate due to blast testing. The simplified model assumes a constant stiffness, mass, and triangular pressure profile to determine the peak deflection of the specimen during an experimental test. The bilinear and nonlinear models are based on the discretization of the wall sections into a number of layers, and using strain-rate dependent, stress-strain relations of the constituent materials to generate stresses within the layers. These stresses then iv form the basis of the resistance function to determine the structural response of the test specimens. In this study, the effect of higher modes of vibration on the test specimens is not included. The bilinear and nonlinear models are then implemented to develop Pressure-Impulse (P-I) diagrams, and the effect of the strain rate on P-I diagrams is investigated. The P-I are then available to be implemented into the recent blast code for reinforced masonry flexural walls. The fitted results of the recorded experimental blast pressure parameters are shown to be adequately approximated by the software ConWep in terms of the peak pressure and specific impulse. Comparing the K-B model, which forms the theoretical basis of ConWep, to the raw pressure profile data obtained from the experimental testing, a significant variations is found in the pressure data while significant scatter is found in the impulse. The analytical results show that increasing the nonlinearity of the material accounts for; the response predicted by the single degree of freedom model more closely relates to the response of the specimens. In addition, strain rate effects have a significant impact on the potential level of protection (LOP) provided by masonry flexural walls, as it has a noticeable effect on the curves of the P-I diagram. / Thesis / Master of Applied Science (MASc)