Academic literature on the topic 'Plates (Engineering) Cracking Testing'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Plates (Engineering) Cracking Testing.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "Plates (Engineering) Cracking Testing"
1
Noori Hoshyar, Azadeh, Maria Rashidi, Ranjith Liyanapathirana, and Bijan Samali. "Algorithm Development for the Non-Destructive Testing of Structural Damage." Applied Sciences 9, no. 14 (July 13, 2019): 2810. http://dx.doi.org/10.3390/app9142810.
Full textAbstract:
Monitoring of structures to identify types of damages that occur under loading is essential in practical applications of civil infrastructure. In this paper, we detect and visualize damage based on several non-destructive testing (NDT) methods. A machine learning (ML) approach based on the Support Vector Machine (SVM) method is developed to prevent misdirection of the event interpretation of what is happening in the material. The objective is to identify cracks in the early stages, to reduce the risk of failure in structures. Theoretical and experimental analyses are derived by computing the performance indicators on the smart aggregate (SA)-based sensor data for concrete and reinforced-concrete (RC) beams. Validity assessment of the proposed indices was addressed through a comparative analysis with traditional SVM. The developed ML algorithms are shown to recognize cracks with a higher accuracy than the traditional SVM. Additionally, we propose different algorithms for microwave- or millimeter-wave imaging of steel plates, composite materials, and metal plates, to identify and visualize cracks. The proposed algorithm for steel plates is based on the gradient magnitude in four directions of an image, and is followed by the edge detection technique. Three algorithms were proposed for each of composite materials and metal plates, and are based on 2D fast Fourier transform (FFT) and hybrid fuzzy c-mean techniques, respectively. The proposed algorithms were able to recognize and visualize the cracking incurred in the structure more efficiently than the traditional techniques. The reported results are expected to be beneficial for NDT-based applications, particularly in civil engineering.
2
Kong, Huan Ping, Chang Kui Liu, De Lin Liu, and Tao Jiang. "Aircraft Bearings Fracture Failure Analysis." Advanced Materials Research 887-888 (February 2014): 319–23. http://dx.doi.org/10.4028/www.scientific.net/amr.887-888.319.
Full textAbstract:
Between aircraft bearings lugs, plates fracture appeared. The failure mode and cause were analyzed by macro and micro observation, EDS analysis, metallographic examination and hardness testing. The results showed that two bearings’ failure were stress corrosion cracking. Bearings’ failure were related with abnormal force state, material cast loose exceeding the allowed limited values played a catalytic role to crack propagation. It is suggested that bearings material surface protection should be strengthened to improve corrosion resistance, bearings design should be optimized to avoid abnormal tensile stress, and material casting process should be improved to reduce cast loose.
3
Wang, Xiao Dong, Rui Ling Jia, Hui Xia Zhang, Hua Jian Lui, Xi Wei Zhai, and Fu Rong Chen. "A Study on the SCC Susceptibility of Twin-Wire Metal Inert Gas Arc Welds in 7A52 Al Alloy Plate." Advanced Materials Research 311-313 (August 2011): 619–23. http://dx.doi.org/10.4028/www.scientific.net/amr.311-313.619.
Full textAbstract:
7A52 Al alloy plates was welded using twin-wire metal inert gas arc welding (TMW) .Stress corrosion cracking (SCC)behavior of the parent material and the welded specimens was investigated by the slow strain rate tensile(SSRT)test method respectively. Electrochemical impedance spectroscopy (EIS) was conducted to understand electrochemical corrosion behavior of 7A52 Al alloy and its TMW weldment. It was found that the welded specimens exhibited higher SCC susceptibility than the parent materials under SSRT testing in seawater. The EIS result showed that the weld zone exhibited higher corrosion resistance than that of the parent material. Hydrogen embrittlement is a crucial factor that leads to the failure of the welded specimens during SSRT test in seawater.
4
Staroverov, Oleg, Elena Strungar, and Valery Wildemann. "Evaluation of the survivability of CFRP honeycomb-cored panels in compression after impact tests." Frattura ed Integrità Strutturale 15, no. 56 (March 28, 2021): 1–15. http://dx.doi.org/10.3221/igf-esis.56.01.
Full textAbstract:
This paper is oriented to the experimental research of the mechanics of the CFRP sandwich plates, glass and carbon fiber sample panels with a large-cell honeycomb core. The method for testing polymer composite sample plates in compression after impact (CAI) tests with joint use of a testing machine and a video system for deformation field registration was tested. Analysis of the experimental data obtained highlighted the impactive sensitivity zone for the test specimens. A quantitative assessment of the load-bearing capacity of glass and carbon fiber sample panels in CAI tests with the different levels of the drop weight impact energy was performed. Photos of samples after impact have been provided. Vic-3D non-contact three-dimensional digital optical system was used to register the displacement and deformation fields on the surface of the samples. The video system was used to evaluate various damage mechanisms, including matrix cracking, delaminations, and rupture of the damaged fibers. The paper studied the evolution of non-homogeneous deformation fields on the surface of the composite samples during the post-impact compression tests and analyzed the configuration of non-homogeneous deformation fields.
5
Dawe, J. L., and C. K. Seah. "Out-of-plane resistance of concrete masonry infilled panels." Canadian Journal of Civil Engineering 16, no. 6 (December 1, 1989): 854–64. http://dx.doi.org/10.1139/l89-128.
Full textAbstract:
Nine large-scale concrete masonry infilled panels (3.6 × 2.8 m) were tested to destruction under uniformly distributed lateral pressure applied in small increments. Load–deformation curves of the infills and the enclosing steel frame showed linear elastic behaviour prior to first cracking. Nonlinear behaviour due to cracking and arching action of infill was prominent in the postcracking range. Parameters investigated experimentally included the effects of boundary supports, joint reinforcement, panel thicknesses, panel opening, and characteristics of construction. In parallel with the testing program, computer-aided analytical techniques were developed to predict the first crack and ultimate loads. First crack prediction was based on a finite element analysis for bending of thick plates, while ultimate load prediction was based on a yield-line technique modified to account for the arching action of infill confined within a flexible frame. Having been verified by comparison with test results, the postcracking analysis program was used to conduct a parametric study. It was found that infill compressive strength, panel dimensions, and frame rigidity have significant effect on ultimate loads. While central openings do not affect the ultimate strength, they do, however, reduce postcracking ductility. Key words: masonry, infill panel, steel frame, experimental, out-of-plane, behaviour, strength, arching, yield-line technique, cracking.
6
Sollier, T., J.-M. Decitre, A. Vigneron, and E. Demaldent. "Simulation of eddy current testing of steam generator tubes with wear and secondary side magnetite deposits." Insight - Non-Destructive Testing and Condition Monitoring 64, no. 2 (February 1, 2022): 73–78. http://dx.doi.org/10.1784/insi.2022.64.2.73.
Full textAbstract:
The steam generator (SG) tubes of pressurised water reactors are prone to degradation and are periodically inspected using eddy current testing (ECT) techniques. SGs provide a safety barrier between the radioactive primary side and the non-radioactive secondary side. Historically, a major degradation issue was stress corrosion cracking of tubes made of alloy 600. In modern SGs, better resistance to stress corrosion cracking is observed with the replacement of alloy 600 by alloy 690. However, this alloy does not prevent tubes from wear at support locations or wear resulting from fretting with loose parts. Long-term operation of SGs also leads to non-volatile species accumulation in the secondary side of the SGs, mainly magnetite. Magnetite deposits may build up as a dense and solid material on top of the tubesheet (hard sludge) and also in the flow slots of tube support plates, therefore modifying the general flow pattern and velocity of the secondary fluid. This has detrimental effects on the safe operation of SGs. The clogging-up ratio of the flow slots therefore needs to be assessed. The development of an ECT simulation model to address tube wear and magnetite deposits in SGs is presented. This model is based on the CIVA NDT platform. A bobbin coil signal is simulated and its performance for tube wear and magnetite deposit evaluation is discussed.
7
Wilhelm, Eugen, Tobias Mente, and Michael Rhode. "Waiting time before NDT of welded offshore steel grades under consideration of delayed hydrogen-assisted cracking." Welding in the World 65, no. 5 (January 28, 2021): 947–59. http://dx.doi.org/10.1007/s40194-020-01060-5.
Full textAbstract:
AbstractOffshore wind turbines (OWT) are a major goal of the energy strategy of Germany encompassing the increase of the installed wind power. OWT components are manufactured from welded steel plates with thicknesses up to 200 mm. The underlying standards and technical recommendations for construction of OWTs encompass specifications of so-called minimum waiting time (MWT) before non-destructive testing of the weld joints is allowed. Reason is the increased risk of time-delayed hydrogen-assisted cold cracking as hydrogen diffusion is very slow due to the very thick plates. The strict consideration of those long MWT up to 48 h during the construction of OWTs leads to significant financial burden (like disproportionately high costs for installer ships as well as storage problems (onshore)). In this study, weld joints made of S355 ML were examined in comparison with the offshore steel grade S460 G2+M. The aim was to optimize, i.e., reduce, the MWT before NDT considering varied heat input, hydrogen concentration and using self-restraint weld tests. This would significantly reduce the manufacturing time and costs of OWT construction. To quantify the necessary delay time until hydrogen-assisted cold cracks appear, acoustic emission analysis was applied directly after welding for at least 48 h.
8
Mamun, Muhammad, and Vivek Bindiganavile. "Mitigating shrinkage cracking in stucco through the replacement of fine aggregate with expanded perlite." Canadian Journal of Civil Engineering 39, no. 8 (August 2012): 906–14. http://dx.doi.org/10.1139/l2012-075.
Full textAbstract:
This paper describes a quantitative study on shrinkage cracking in stucco. Two series of mixes were examined with the binder to fine aggregate volumetric ratio of 0.20 and 0.25, respectively. In each series, specially engineered expanded perlite was incorporated as a replacement to the fine aggregate at up to 75% by volume. An environmental chamber was setup to create extreme conditions for moisture loss through sustained high temperature and low humidity. Commercially recommended stucco mixes were cast into plates, which were evaluated for linear and volumetric shrinkage. At the same time, crack growth at the end of a 48 h exposure period was evaluated for total length and area. It was found that while adding expanded perlite did not notably reduce the total linear or volumetric shrinkage, it significantly lessened crack development. This was attributed to the increase in tensile strain capacity imparted by the expanded perlite, as evidenced from flexural testing.
9
Héritier, Bernard, François Olard, Frédéric Loup, and Serge Krafft. "Design of a Specific Bituminous Surfacing for the World's Highest Orthotropic Steel Deck Bridge." Transportation Research Record: Journal of the Transportation Research Board 1929, no. 1 (January 2005): 141–48. http://dx.doi.org/10.1177/0361198105192900117.
Full textAbstract:
This paper presents a rational approach for the performance-based design of bituminous wearing surfacings on orthogonally anisotropic steel bridges. The behavior of bituminous surfacings on steel orthotropic decks under heavy truck traffic and environmental conditions is highly complex. Both the geometry of the structure and the high flexibility of metallic plates make the deformations and stresses severe in steel bridge surfacings. In particular, the repeated loading makes the fatigue strength an important parameter for the design of such bituminous wearing courses. In addition, these specific surfacings must have durability over the expected temperature range, and they must be resistant to thermal cracking at low temperatures and to rutting at high temperatures. The technical studies that were conducted in parallel with the construction of the Millau Viaduct (France)–-the world's highest bridge–-have provided in particular the opportunity for progress in the development of appropriate laboratory testing equipment and of an original polymer-modified surfacing. A comprehensive research program, including both a large laboratory testing campaign and a finite element parametric study, was performed to develop a useful tool for the design of plate surfacings.
10
Karve, Pranav, Sarah Miele, Kyle Neal, Sankaran Mahadevan, Vivek Agarwal, Eric R. Giannini, and Patricia Kyslinger. "Vibro-acoustic modulation and data fusion for localizing alkali–silica reaction–induced damage in concrete." Structural Health Monitoring 19, no. 6 (February 27, 2020): 1905–23. http://dx.doi.org/10.1177/1475921720905509.
Full textAbstract:
This article investigates the application of vibro-acoustic modulation testing for diagnosing damage in concrete structures. The vibro-acoustic modulation technique employs two excitation frequencies on a structure. The interaction of these excitations in the measured response indicates damage through the presence of sidebands in the frequency spectra. Past studies using this technique have mostly focused on metals and composites (thin plates or laminates). Our research focuses on concrete, which is a highly heterogeneous material susceptible to a variety of chemical, physical, and mechanical damage processes. In particular, this article investigates diagnosing cracking in concrete from an expansive gel produced by an alkali–silica reaction in the presence of moisture. Past studies have been limited to damage detection using vibro-acoustic modulation testing, whereas this article extends the technique to damage localization. A cement slab with pockets of reactive aggregate is used to investigate the diagnosis technique. The effects of different testing parameters, such as locations, magnitudes, and frequencies of the two excitations, are analyzed and incorporated in the damage localization methodology. A Bayesian probabilistic methodology is developed to fuse the information from multiple test configurations in order to construct damage probability maps for the test specimen. The results of vibro-acoustic modulation–based damage localization are validated by petrographic study of cores taken from the slab.
Dissertations / Theses on the topic "Plates (Engineering) Cracking Testing"
1
Abayakoon, Sarath Bandara Samarasinghe. "Large deflection elastic-plastic analysis of plate structures by the finite strip method." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26946.
Full textAbstract:
A solution procedure based on the finite strip method is presented herein, for the analysis of plate systems exhibiting geometric and material non-linearities. Special emphasis is given to the particular problem of rectangular plates with stiffeners running in a direction parallel to one side of the plate. The finite strip method is selected for the analysis as the geometry of the problem is well suited for the application of this method and also as the problem is too complicated to solve analytically.
Large deflection effects are included in the present study, by taking first, order non-linearities in strain-displacement relations into account. Material non-linearities are handled by following von-Mises yield criterion and associated flow rule. A bi-linear stress-strain relationship is assumed for the plate material, if tested under uniaxial conditions. Numerical integration of virtual work equations is performed by employing Gauss quadrature. The number of integration points required in a given direction is determined either by observing the individual terms to be integrated or by previous experience. The final set of non-linear equations is solved via a Newton-Raphson iterative scheme, starting with the linear solution.
Numerical investigations are carried out by applying the finite strip computer programme
to analyse uniformly loaded rectangular and I beams with both simply supported and clamped ends. Displacements, stresses and moments along the beam are compared with analytical solutions in linear analyses and with finite element solutions in non-linear analyses. Investigations are also extended to determine the response of laterally loaded square plates with simply supported and clamped boundaries. Finally, a uniformly loaded stiffened panel is analysed and the results are compared with finite element results. It was revealed that a single mode in the strip direction was sufficient to yield engineering accuracy for design purposes, with most problems.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
2
Underwood, Nicholas. "Pulse pressure testing and analysis of steel plates with openings." Thesis, University of Liverpool, 2013. http://livrepository.liverpool.ac.uk/15273/.
Full textAbstract:
Steel plates are widely used in a variety of civil engineering applications for load bearing structural components, due to their favourable strength to weight ratio. Many of these plates have openings that are commonly used for reducing weight, access for utilities or for inspection in shipping and offshore installations. However the influence of these openings to the structural component’s robustness and resilience against blast loading is relatively unknown, with limited research conducted in this subject to date. Due to the high costs associated with offshore facilities they are typically very congested. This coupled with the producing, processing, storing and transporting of hydrocarbon materials means that explosions and subsequent fires are major hazards with severe consequences. In the event of an explosion, the blast load will initially impact the secondary structure (large spanning plated sections) and then transfer through to the primary structure, highlighting their critical consideration in safety assessments. Plated structures are also known to cause confinement, which in turn will results in higher overpressures, making the consequences of an event more severe. The aim of this research was to investigate the combined influence that openings have on the overpressure and the structural response of thin ductile plates subjected to extreme dynamic transverse loads. This was achieved by conducting a set of well-defined experiments investigating the response of 1/8 scale (0.5 m square) mild steel plates with openings subjected to pulse pressure loading. Six central (scaled) openings were considered; circular (50, 75 and 100 mm) and extended circular (50 by 75, 75 by 100 and 100 by 125 mm) representative of typical offshore and shipping applications. Each plate design was assessed with two boundary conditions (restrained and non-restrained) and two nominal loading conditions. The boundary conditions adopted in this study allowed the response to be bounded, and enabled them to be practicably modelled in FEA-analyses and in the simplified analytical approaches. A pulse pressure test facility was used to generate nominal pulse pressure loads (25 and 50 psi) applied over a time (100 to 200+ ms load duration) representative of extreme explosion loading conditions offshore. All plates exhibited a mode I type failure (large inelastic deformation) highlighting the large reserve strength in such members. The work has shown that the inclusion of an opening (<5% of the exposed panel area) does not significantly degrade the structural resistance when damage is restricted to large inelastic deformation. The reduction in stiffness due to the hole is compensated by the reduced area to which the load is applied. The data generated in the laboratory tests was used to develop and validate finite element models. In general, excellent correlation was observed between the experimental failure modes and the permanent displacements, within an average difference of 12% and 15% for the restrained and non-restrained plates respectively. The finite element models also provided a useful insight into the various failure processes and transient behaviour which could not be observed experimentally. A simplified analytical model was developed to predict the response of the plates and was validated against the experimental data. The results for the permanent displacements compared favourably with the restrained plates at the two nominal pressures (6.5% at 25 psi and 7% at 50 psi), but correlated less well with the non- restrained ones (10% at 25 psi and 3% at 50 psi). Correct definition of support conditions along with a detailed description of the development of plasticity, as shown in the finite element models was fundamental in accurately predicting response of the non-restrained plates. The simplified techniques developed are cost effective compared with more sophisticated finite element methods making them suitable for preliminary engineering design studies. Ultimately this study provides evidence to suggest that small (circular or extended circular) openings positioned away from areas of high stress, could be used as a passive system to mitigate the influences of an explosion event offshore. This has many benefits in the form of reducing weight, reducing confinement (thus lowering overpressures) and reducing the loading applied to these members, and subsequently reducing the loading transferred through to the primary structure.
3
Williams, Karen Margaret. "Design, analysis and testing of non metallic rockbolt bearing plates." Thesis, Sheffield Hallam University, 1998. http://shura.shu.ac.uk/20543/.
Full textAbstract:
Non metallic bearing plates have been identified as the weakest component in GRP rockbolting systems used in UK coal mines. A literature review revealed a shortage of information on the design of rockbolting components, particularly the design of the non metallic bearing plates. Over twenty parameters concerning the design and testing of non metallic rockbolt bearing plates have been investigated using Finite Element Analysis and laboratory testing. The parameters included bearing plate depth, central hole diameter, external diameter, material, coned angle for both solid and webbed bearing plates. The designs have been evaluated by comparing the load/plate volume to consider the efficient use of the material. The experiments were designed using Taguchi and one factor at a time methodologies. Interactions between some parameters have been investigated. Reasons for the observed effect of parameters have been suggested. A modification of the BS 7861 test is proposed which more closely simulates the colliery failure mechanism and hence gives a better measure of a bearing plate's suitability for use in a coal mine. The modified test uses a 100 mm hole in the steel support plate as specified by American Standard F432 for steel rockbolt bearing plates, not the 55 mm hole as specified by BS 7861.Optimum values for important parameters have been determined for a 100 mm hole in the steel support plate as proposed in this research and for the 55 mm hole diameter specified by BS 7861. The results produced can be used to design a bearing plate for use in a coal mine with optimum depth and coned angle.
4
Martin, Anthony George. "The ultimate load capacity of square shear plates with circular perforations : (parameter study)." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/25119.
Full textAbstract:
The incremental structural analysis program NISA83 was used to investigate various parameters affecting the ultimate capacity of square plates with circular perforations subjected to uniform shear stress. Both nonlinear material properties and nonlinear geometry were taken into account in determining the ultimate in-plane capacities and buckling capacities of perforated shear plates.
The parameters investigated during this study were the hole size for a concentric location, and the hole location for a constant ratio of hole diameter to plate width of 0.2. In addition various doubler plates were studied to determine the most effective shape to restore a shear plate to its original ultimate in-plane capacity.
For the first two parameters, the analysis was separated into three parts. The ultimate in-plane capacity, elastic buckling capacity and the ultimate elastic-plastic buckling capacity was determined for each combination of the two parameters. These were used to identify the importance of both elastic buckling and nonlinear material contribute to the reduced ultimate plate capacities.
The results from plates with a concentrically located hole of varying size showed excellent correlation with other published experimental and analytical results for both the in-plane capacity and the 3-dimensional buckling capacities.
Variation of the center location of a hole of a standard size provided some significant results. Little change was found in the ultimate in-plane capacity for all hole locations. On the other hand, the elastic buckling capacity was raised by 50% after moving the hole from the plate tension diagonal to the compression diagonal. Finally, from the ultimate elastic-plastic' buckling capacity results it was concluded that the concentric provides lower bound capacity for all other hole locations. The in-plane analysis of the optimum doubler plate size showed wide and thin plates to be more effective than narrow and thick plates. A doubler plate with the same thickness as the plate and twice the diameter of the hole is recommended to restore the perforated plate to its original in-plane capacity.
In order to aid in the tedious task of checking the input data and to provide a convenient way of displaying the result, a full graphic post-processor was developed as part of this thesis. The program NISPLOT used color graphics available at the UBC Civil Engineering lab to process the output from NISA83. It was written in FORTRAN 77, utilizing subroutines from a commercial graphics package, DI3000, to obtain device independent graphics. NISPLOT generated plots of the nodes and element mesh for each data check. When a complete analysis was carried out by NISA83, nodes, element mesh, deflected shape, and color stress fill plots were generated.Applied Science, Faculty of
Civil Engineering, Department of
Graduate
5
Kametz, David Austin. "Precision Fabrication and Development of Charging and Testing Methods of Fixed-Abrasive Lapping Plates." NCSU, 2002. http://www.lib.ncsu.edu/theses/available/etd-07092002-084606/.
Full textAbstract:
The recording head industry is one of the dominant users of advanced ceramics such as alumina, silicon nitride, silicon carbide and AlTiC. The high hardness of these materials makes diamond the optimal abrasive for machining. One challenge when manufacturing recording heads for rigid disk drives is to generate surfaces that are both planar and smooth. Flatness tolerances are in the range of a few tens of nanometers to a few hundred nanometers per millimeter of length [1]. Roughness tolerances are in the range of a few nanometers to the subnanometer range [1]. Fixed-abrasive lapping, sometimes called nanogrinding, is a common method of machining used on ceramics. Fixed-abrasive lapping is generally a two-body abrasive process, with the abrasive grain fixed in the lapping plate that produces an extremely smooth surface due to the controlled depth of cut. The process of fabricating a quality fixed-abrasive lapping plate is a lengthy and sometimes demanding process. The goals of this research are to investigate the current fabrication process for improvements in surface texture quality, charging time and waste reduction of abrasive as well as the development of methods and equipment capable of estimating the lapping qualities of the plate during it?s fabrication process. The improvement of this process will reduce plate fabrication time and improve lapping performance. Current processes used to fabricate a plate can require 2 hours or more, and often the lapping quality of the plate is unknown until it is used. The research started by analyzing the current process used. The surface texture and charging quality were analyzed by quantifying characteristics such as surface roughness, kurtosis, bearing ratio and diamond concentration. The new process developed at the Precision Engineering Center changed the surface texture from scratches of random geometry to a continuous spiral groove cut by a diamond turning machine. This texture not only has better reproducibility than the random scratches, but the geometry of the individual features can be better controlled. The charging mechanism was also changed from a large charging ring that was half the diameter of the lapping plate to a small rolling cylinder. The cylinder creates higher pressures and the ability to follow the profile of the plate. These changes created a shorter charging time, higher charging quality and reduced abrasive waste during the charging process. A tribometer was developed to test the charging quality of the plate during the charging process. It took advantage of the changing friction coefficient on the surface of the plate with charging time. The mechanism constructed and tested did not perform as designed, but can be used as a prototype for future developments. The use of other equipment for charging verification utilizing friction or other aspects of the charging process is viable.
6
Phillips, John L. "Structural analysis and optimum design of geodesically stiffened composite panels." Thesis, This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-03122009-040802/.
Full text
7
Zheng, Tieyu. "A study of residual stresses in thin anisotropic (silicon) plates." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/17516.
Full text
8
Baah, Prince. "Cracking Behavior of Structural Slab Bridge Decks." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1417539467.
Full text
9
Boitnott, Richard L. "Nonlinear response and failure characteristics of internally pressurized composite cylindrical panels." Diss., Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/54381.
Full textAbstract:
Results of an experimental and analytical study of the nonlinear response and failure characteristics of internally pressurized 4- to 16-ply-thick graphite-epoxy cylindrical panels are presented. Specimens with clamped boundaries simulating the skin between two frames and two stringers of a typical transport fuselage were tested to failure. Failure results of aluminum specimens are compared with the graphite-epoxy test results. The specimens failed at their edges where the local bending gradients and interlaminar stresses are maximum. STAGS nonlinear two-dimensional shell analysis computer code results are used to identify regions of the panels where the response is independent of the axial coordinate. A geometrically nonlinear one-dimensional cylindrical panel analysis was derived and used to determine panel response and interlaminar stresses. Inclusion of the geometric nonlinearity was essential for accurate prediction of panel response. Measurements of panel radius and edge circumferential displacements associated with specimen slipping were also required in the one-dimensional analysis for good correlation between analytical and experimental results.
Some panels failed with significant damage in the form of tensile fiber breaks and ply delaminations preceding the ultimate pressure. Other panels failed suddenly without any apparent damage preceding the ultimate pressure. The failure usually occurred along one edge of the panel leaving the other edge intact. The damage on the panel surfaces and through-the-thickness were examined to determine the failure characteristics of the panels. Various failure criteria were applied to the stresses predicted from the one-dimensional analysis. The maximum stress failure criterion applied to the predicted tensile stress in the fiber direction agreed best with the experimentally determined first damage pressures. Results indicate that all panels tested would support applied internal pressures well above fuselage proof pressures.Ph. D.
10
Kalabon, Amy Elizabeth. "Implementation and Field Testing of Improved Bridge Parapet Designs." Cleveland State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=csu1399314661.
Full textBooks on the topic "Plates (Engineering) Cracking Testing"
1
Finn, Scott R. Composite plates impact damage: An atlas. Lancaster, Pa: Technomic Pub. Co., 1991.
Find full text
2
ASME Pressure Vessels and Piping Conference. (1988 Pittsburgh, Pa.). Advances in dynamic analysis of plates and shells - 1988: Presented at the 1988 ASME Pressure Vessels and Piping Conference, Pittsburgh, Pennsylvania, June 19-23, 1988 : sponsored by the Pressure Vessels and Piping Division, ASME. New York: American Society of Mechanical Engineers, 1988.
Find full text
3
Elmore, Lisa. Cracking the MCAS. New York: Random House, 2000.
Find full text
4
Schra, L. Long-term outdoor stress corrosion testing of overaged 7000 series aluminium alloys. Amsterdam: National Aerospace Laboratory, 1988.
Find full text
5
Pressure Vessels and Piping Conference (1986 Chicago, Ill.). Nonlinear analysis and NDE of composite material vessels and components: Presented at the 1986 Pressure Vessels and Piping Conference and Exhibition, Chicago, Illinois, July 20-24, 1986. New York, N.Y. (345 E. 47th St., New York 10017): American Society of Mechanical Engineers, 1986.
Find full text
6
D, Kane R., ed. Slow strain rate testing for the evaluation of environmentally induced cracking: Research and engineering applications. Philadelphia: ASTM, 1993.
Find full text
7
Laufenberg, Theodore. Creep testing of structural composite panels: A literature review and proposed standards. [Madison, Wis.?: Forest Products Laboratory, 1987.
Find full text
8
Nemirovskiĭ, I︠U︡ V. Dinamicheskoe soprotivlenie ploskikh plasticheskikh pregrad. Novosibirsk: GEO, 2009.
Find full text
9
Kane, RD, ed. Slow Strain Rate Testing for the Evaluation of Environmentally Induced Cracking: Research and Engineering Applications. 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959: ASTM International, 1993. http://dx.doi.org/10.1520/stp1210-eb.
Full text
10
N, Kringos, Al-Qadi I, A. Loizos, and SpringerLink (Online service), eds. 7th RILEM International Conference on Cracking in Pavements: Mechanisms, Modeling, Testing, Detection and Prevention Case Histories. Dordrecht: Springer Netherlands, 2012.
Find full textBook chapters on the topic "Plates (Engineering) Cracking Testing"
1
Eschbach, Lukas, Andreas Marti, and Beat Gasser. "Fretting Corrosion Testing of Internal Fixation Plates and Screws." In Materials for Medical Engineering, 199–204. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2005. http://dx.doi.org/10.1002/3527606149.ch27.
Full text
2
Ghosh, Swarnangshu, Rithik Agrawal, and R. Vidya Sagar. "Implementation of Acoustic Emission Testing to Study the Type of Cracking in Reinforced Concrete Beams." In Lecture Notes in Mechanical Engineering, 283–96. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-0186-6_28.
Full text
3
Pineau, Pierre, Guillaume Couégnat, and Jacques Lamon. "Virtual Testing and Simulation of Multiple Cracking in Transverse Tows of Woven CMCs." In Mechanical Properties and Performance of Engineering Ceramics and Composites V, 319–28. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2010. http://dx.doi.org/10.1002/9780470944127.ch30.
Full text
4
Falbr, Jan. "Bending Capacity of Thin UHPC Plates Based on Theoretical Predictions and In-situ Testing." In High Tech Concrete: Where Technology and Engineering Meet, 439–46. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-59471-2_53.
Full text
5
Hussain, Muzamal, and Muhammad Nawaz Naeem. "Effect of Various Edge Conditions on Free-Vibration Characteristics of Isotropic Square and Rectangular Plates." In Advanced Engineering Testing. InTech, 2018. http://dx.doi.org/10.5772/intechopen.80672.
Full text
6
Pal, Sagarika, Ramtanu Mukherjee, and Sharmi Ganguly. "Design, Development and Testing of a Semi Cylindrical Capacitive Array Type Liquid Interface Level Sensor." In Advanced Instrument Engineering, 247–56. IGI Global, 2013. http://dx.doi.org/10.4018/978-1-4666-4165-5.ch018.
Full textAbstract:
In this study, a semi cylindrical capacitive array type liquid interface level measuring sensor is described. The sensor consists of a continuous large semi cylindrical thin metallic plate acting as a common plate of the capacitor and an array of small semi cylindrical thin metallic plates, separated by very small gap distance. All plates are mounted along the outer wall of a cylindrical non conducting vertical storage tank. The detection of liquid interface is based on the measurement of capacitance of the array of plates which varies with the dielectric constant of the liquid within the tank. The measured capacitance has been obtained in nano farad range. Since the sensor is non contact type, it can be used for both conducting and non conducting type of liquid contained within a non conducting tank. Experimental results confirm the satisfactory performance of the sensor for liquid interface level measurement.
7
Abdewi, E. F. "Experimental Testing of Corrugated Composite Plates with Sinusoidal Profile as an Energy Absorber." In Reference Module in Materials Science and Materials Engineering. Elsevier, 2016. http://dx.doi.org/10.1016/b978-0-12-803581-8.04092-3.
Full text
8
Hołowaty, Janusz, and Bernard Wichtowski. "Quality and Fatigue Assessment of Welded Railway Bridge Components by Testing." In Engineering Principles - Welding and Residual Stresses [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.104439.
Full textAbstract:
During a decades-long program from 1953 to 1990, the quality of welded joints in railway bridges in Poland was assessed and quantified. It was discovered that many welded joints have technological cracks, and their quality is poor, especially in old constructions. Nearly, 200 bridges were tested using X-ray examination. The number of joints tested was over 15,000; cracks were discovered in 400 welded joints in the 34 bridges tested. To solve the problem, repeated examinations on welded joints with imperfections were undertaken and laboratory fatigue tests were performed. The tests and numerical analysis allowed fatigue behavior and tensile stresses in welded butt splices with cover plates to be recognized and excluded such a structural solution in bridges. The existing discontinuities and imperfections in welded joints following many years in service show no growths or forming of new cracks, as the applied stresses are below the threshold fatigue strength. As a result of decades of service, steel bridges undergo functional aging, and their structural steels undergo structural aging. There is a need to both harmonize differentiated procedures and create national recommendations to assess their safe endurance. Therefore, of use may be the findings presented in the chapter.
Conference papers on the topic "Plates (Engineering) Cracking Testing"
1
Gra˚berg, Stig, Lars Volden, and Anthonius Johannes Paauw. "Mid Thickness Delayed Cracking of Z-Quality Offshore Steel." In ASME 2011 30th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2011. http://dx.doi.org/10.1115/omae2011-49003.
Full textAbstract:
During fabrication of a steel structure for an offshore modification project, delayed cracking was experienced in the mid plane or centre line of a 30 mm thick plate. The plate was part of a restraint box frame where 25 mm plates were welded to this 30 mm plate on both plate-surfaces. The applied 30 mm plate was a higher strength offshore steel (EN10225-S420 G2+M), with special through thickness properties and enhanced chemical composition as defined in material data sheet MDS Y30 of NORSOK M-120. Fracture mechanical testing including KV and CTOD in the mid plane confirmed that a very low toughness was present here with a brittle fracture type (cleavage). The plate was manufactured by the continuous casting process which due to centre line segregation resulted in high levels of manganese sulfide inclusions but also niobium carbides/nitrides. The plate manufacturer considered the documented toughness level as expected. Similar testing was performed on a 30 mm plate also delivered to the same material specification but of which the material certificate revealed a 10 times lower sulfur and phosphorus content indicating a much higher steel refinement. A significant higher toughness was obtained for this steel with high ductile behavior. Both steels showed a similar through thickness ductility, measured elongation for the through thickness tensile specimen, which implies that this property does not guaranty for the observed material behavior.
2
Lotsberg, Inge, Arne Fjeldstad, Morten Ro Helsem, and Narve Oma. "Fatigue Life Improvement of Welded Doubling Plates." In ASME 2012 31st International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/omae2012-83683.
Full textAbstract:
Fatigue life assessment is important for all floating offshore structures related to the new building stage but also related to lifetime extensions. Fatigue cracking occurs normally due to uncertainties in estimated fatigue life and this is a well-known problem for floaters. In this paper the aim has been to look deeper into the effects of improvement methods for improvement of the fatigue life of structural connections. Fatigue testing of full size fillet welded doubling plates has been performed of a specimen in as welded condition for comparison with two specimens improved by grinding. The paper also presents an alternative S-N curve for grinded details. The primary goal is to assess the possibility for fatigue life improvement of fillet welded doubling plates where fatigue cracking may initiate from the weld root. The information gained in this project is considered to be important for the offshore floater industry, as well as for development of new fatigue assessment procedures and requirements in standardization.
3
Al-Rifaie, Wail, and Waleed K. Ahmed. "An Experimental Investigation on the Shear Strength of Ferrocement Reinforced With Hexagonal Mesh." In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-50213.
Full textAbstract:
Ferrocement is characterized by fine diameter mesh reinforcement, and size of mesh opening, and the surface area per unit volume of mortar may be as much as ten times that in conventional reinforced concrete. The behavior of ferrocement is characterized by volume fraction of the fibers Vfx and Vfy in x and y directions and the specific surfaces of the mesh SLx and SLy. An experimental investigation on the shear strength of ferrocement plate reinforced with hexagonal mesh is carried out. Ferrocement square plate specimens were cast and tested. A total of 24 simply supported square plates (500×500mm) having mortar with cement/ sand proportions 1: 2 and 1: 3 by weight have been cast and tested under ‘patch’ load varying the number of mesh layers, the plate thickness, the size of the mesh opening and the arrangement and orientation of the mesh. Woven hexagonal mesh has been used. All plate specimens have been tested with their edges simply supported over a span of 450mm in two directions. During tests, central patch loads of size 100×100mm at the center of each plate specimens were applied to the models through a universal testing machine of 250 ton capacity. Having located the specimens within its support, series of patch load increments were then applied to the plate up to failure loads. The plate behavior has been presented in the form of the first cracking load Pcr and the ultimate load Pu which is the total patch load at failure. It was observed that the first cracking load is influenced by the ultimate mortar strength and not much affected by volume content of reinforcement. The slope of the curves at collapse indicates that the load carrying capacity is highly influenced by the steel volume content and the tensile strength of the mesh reinforcement while the contribution of mortar is negligible. The failure loads in the plates with closely spaced wires were higher as compared to the plates with widely spaced wires. There is an increase in the value of failure load Pu for the plate specimens with orthogonally oriented mesh layers as compared to the specimens with twin layers. An important conclusions regarding the plate behavior are drawn and expression to estimate the first cracking load is proposed. A comparison of the first cracking load values with those obtained using the proposed expression. It is seen that the proposed expression gives a reasonable estimate of the first cracking load.
4
Brady, Brian G. "Cracking During the Installation of Interference Fit Fasteners and Bucked Rivets in 7050-T7XXX Machined Aluminum Parts." In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-14815.
Full textAbstract:
This test program evaluated the effect of the installation of solid rivets and interference fit Hi-Tigue bolts on machined 7050 longerons (HiTigue is a registered trademark of the Hi-Shear Corporation of Torrance, (CA). Two simulated longeron specimens were machined from both 7050-T7451 and 7050-T7651 plate. Titanium Hi-Tigues and solid aluminum and Monel rivets were then installed with a pneumatic riveting hammer in sections of various thicknesses in the four machined longeron specimens. After all fasteners were installed, each fastener was subjected to a simulated mishap by applying the pneumatic riveting hammer to the installed fastener without support from an underlying bucking bar. Dye penetrant inspections to detect cracks were performed after the fastener installations and simulated mishaps. All fasteners were then removed and the open holes subjected to eddy current inspection. Visual observations concerning deformation of the machined longeron specimens during fastener installations and simulated mishaps were recorded. Cracking was noted in 0.063 inch thick longeron sections, compelling additional testing involving Hi-Tigues. Recommendations concerning the use of Hi-Tigues and solid rivets in 7050-T7XXX machined parts were made based on the results of the testing.
5
Hsu, T. M., Jaime Buitrago, Arthur Herman, and Peter C. McKeighan. "Fatigue Performance of Friction Welded Studs." In ASME 2005 24th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2005. http://dx.doi.org/10.1115/omae2005-67209.
Full textAbstract:
Early in the life of the Genesis spar, cracking developed at the welded connections between the riser guide supports and the hull wall plate. The cracking was caused by the movements of the top-tensioned risers within the steel guide frames in the moon pool of the structure. The remedial action taken to minimize the riser movements and its effects on the hull involved the use of novel rubber bumpers, which were installed in lieu of the steel guides. The bumpers around the periphery of the moon pool were fastened to the hull wall via threaded studs that were friction welded to the hull wall plate underwater. This paper describes a testing program specifically designed to qualify the fatigue performance of the stud-plate friction welds. Results verify the use of the F2 S-N curve from British Standard 7608 with a single slope for the design of the friction-welded connections subjected to axial load. It was also found that the fatigue performance of friction welds is sensitive to the stud preload. One unique feature of the fatigue failure mode of the connection, when the load is transferred through the stud into the plate, is that cracking takes place along the semi-circular heat-affected zone (HAZ) of the bond-line between the stud and the plate, and not through the hull plate thickness. As a result, failure of a stud connection does not compromise the structural integrity of the spar hull.
6
Zhang, Y. H., and A. Stacey. "Review and Assessment of Fatigue Data for Offshore Structural Components Containing Through-Thickness Cracks." In ASME 2008 27th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2008. http://dx.doi.org/10.1115/omae2008-57503.
Full textAbstract:
In recent years, structural integrity management schemes for offshore installations have placed increased reliance on the use of flooded member detection (FMD) as the principal inspection method. This method can be routinely employed in a remotely operated vehicle, which enables a large number of members to be inspected fairly quickly at a much reduced cost compared to using diver operated techniques. However, reliance on FMD for safety assurance requires that welded joints retain sufficient fatigue life and static strength after through-thickness cracking. A comprehensive examination of published work containing data on fatigue lives beyond through-thickness cracking in offshore structures was carried out, resulting in the development of a database of 281 relevant tests. The database was used to perform a statistical assessment of the effects of different testing conditions and geometrical parameters on the remaining fatigue life beyond the occurrence of through-thickness cracking, N3, which was represented by a parameter Re. Whilst the data showed a large amount of scatter, it was found that Re depends strongly on chord thickness, loading mode, type of joint and testing environment. In some cases, a significant amount of remaining life existed. This was often associated with T-type tubular joints with thin chord thickness under out-of-plane loading and a seawater (with CP) environment. The influence of the relevant parameters on Re is discussed and attributed to their effect on crack shape, stress distribution, cracking location and crack propagation path.
7
Guixiang, Yi, and Li Liang. "Cause Analysis and Influence Evaluation of Cracks in Thick Slab Construction." In 2021 28th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/icone28-64548.
Full textAbstract:
Abstract Cracks were found in the slab of a nuclear power plant when the formwork was removed. By means of ultrasonic testing, water storage test and crack width detection, the fracture distribution, depth and width characteristics are determined. On this basis, the numerical simulation analysis of hydration heat in the maintenance process is carried out to simulate the possible crack generation and distribution of the floor slab in the maintenance process. The simulation result shows that cracks under the combined action of temperature and shrinkage are consistent with the cracking characteristics of floor slab. Through numerical simulation of the cracked floor and intact floor, the change of the out of plane bearing capacity (bending and shear) of the cracked floor is compared and analyzed. In the model, considering the reduction of the bearing capacity at the crack section and the change of load transfer effect at the crack interface, the concrete model is disconnected according to the known opening situation, and the contact relationship is set on the crack interface to simulate the crack. Through comparative analysis, the mechanical properties of the cracked floor are evaluated, and the refined numerical simulation method of the working components with cracks is proposed. This paper can provide guidance for the cause analysis and influence evaluation of similar thick plate cracking phenomenon.
8
Newbury, B. D., D. P. Fairchild, C. A. Prescott, T. D. Anderson, and A. J. Wasson. "Qualification of TMCP Pipe for Severe Sour Service: Mitigation of Local Hard Zones." In ASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/omae2019-96614.
Full textAbstract:
Abstract C-Mn steels are extensively used as line pipe material for sour service oil and gas applications, i.e. in the presence of hydrogen sulfide (H2S), because of their ease of fabrication, weldability and significantly lower cost compared to Corrosion Resistant Alloys (CRAs). However, use of C-Mn steel in sour conditions can be limited by its susceptibility to various hydrogen damage mechanisms such as sulfide stress cracking (SSC) and hydrogen induced cracking (HIC). Presently, there are several industry standards which provide guidelines for materials selection and qualification testing to ensure the integrity of carbon steel pipelines in sour service. In recent years, examples of line pipe susceptibility to SSC have occurred due to undetected Local Hard Zones (LHZs) produced during steel plate manufacture. A companion paper (Fairchild, et al, [1]) describes historical and one newly recognized root causes for LHZs. Due to this newly recognized root cause, the adequacy of the current industry practice for specifying and qualifying C-Mn line pipe for severe sour service should be evaluated. In this work, a new approach to monitoring steel plate manufacture during Thermo Mechanical Controlled Processing (TMCP) in order to manage LHZs is explained. Results from implementing this qualification approach will be discussed. In addition, several gaps were identified in the current test methods and various potential modifications to address these gaps were identified. Based on the results of these studies, recommendations to the test methods are made to improve the robustness in the materials qualification process used for sour pipeline projects.
9
Aljets, Dirk, Alex Chong, and Steve Wilcox. "Acoustic Emission Source Location During the Monitoring of Composite Fracture Using a Closely Arranged Sensor Array." In ASME 2011 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/detc2011-48878.
Full textAbstract:
Acoustic Emission (AE) has become a powerful tool for Non-Destructive Testing (NDT) and Structural Health Monitoring (SHM) to identify and locate damage in engineering structures. Propagation cracks and other damages emit stress waves which can be detected by suitable sensors mounted on the structures surface. AE is becoming more and more popular for composite structures since it is not only able to monitor a relative large area at a time and without scanning but also because it is able to detect and potentially discriminate all different failure types such as matrix cracking, delamination and fibre breakage. In order to identify the location of AE sources in large plate-like structures it typically requires the use of at least three widely spaced sensors. The distance between these sensors is defined by, for example, expected AE intensity and attenuation of the signals. This paper presents AE monitoring results from a tensile test on a composite plate. The origin of each AE event was located using a novel configuration of the three sensors, which were installed in a closely arranged triangular array with the sensors just 45 mm apart. The algorithm locates AE sources by determining the direction from which the wave approaches the array using the time of arrival and the distance the wave has travelled using the wave mode separation. The test was conducted on a carbon fibre reinforced composite (CFRP) plate with anisotropic lay-up. The technique is particularly suitable for NDT and SHM applications where the close positioning of the sensors allows the array to be installed in one housing to simplify mounting and wiring.
10
Richards, Mark D., Timothy S. Weeks, J. David McColskey, Bo Wang, and Yong-Yi Wang. "Fatigue Pre-Cracking Curved Wide Plates in Bending." In 2010 8th International Pipeline Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/ipc2010-31468.
Full textAbstract:
Curved wide plate (CWP) testing in tension, on API 5L X100 pipes of 36-inch (916-mm) diameter and 0.75-inch (19-mm) wall thickness, has been initiated in support of strain-based design using high strength steel for oil and gas pipeline applications. The CWP tests are being used to optimize and validate welding procedures and to determine the defect tolerance within the girth welds. A traditional pre-requisite for fracture mechanics testing is a final extension of a crack via fatigue pre-cracking to produce a representative flaw. A method of fatigue pre-cracking CWP specimens for final notch preparation in bending was developed to meet ASTM guidelines for fracture mechanics testing. Fatigue pre-cracking for the present specimen geometry was possible in bending due to lower requisite force capacity equipment which allowed for greater cyclic loading frequencies. In order to achieve sufficient stress levels for fatigue crack growth in the curved plate, a stress field analysis was performed to optimize the loading support configuration in four-point bending. In addition to the stress field analysis, a 3-D finite element model of the CWP specimen was generated to analyze the notched CWP specimen in four-point bending. Finite element analysis (FEA) results and experimental data were used to confirm the hypothesis that, under the proposed loading arrangement, the closed-form solutions for stress-intensity (K) of flat plates in bending can be used to approximate the K for CWP specimens in bending. Validation of a solution for stress-intensity factor subsequently allowed the determination of force amplitude levels for fatigue crack growth. Force and crack mouth opening displacement (CMOD) data were analyzed to correlate compliance with crack length measurements. From experimental results, a method was developed that enable the repeatable and well characterized extension of surface flaws by fatigue pre-cracking in curved wide plate specimens in bending.
Reports on the topic "Plates (Engineering) Cracking Testing"
1
Rahbar-Rastegar, Reyhaneh, Gerald Huber, Miguel A. Montoya, Christopher Campbell, and John E. Haddock. Demonstration Project for Asphalt Performance Engineered Mixture Design Testing. Purdue University, 2022. http://dx.doi.org/10.5703/1288284317382.
Full textAbstract:
The asphalt industry is moving towards performance-based methods for asphalt mixture design. The Federal HighwayAdministration (FHWA) is supportive of state departments of transportations (DOT) adopting index and predictive performance tests, especially those making use of the Asphalt Mixture Performance Tester (AMPT). The FHWA is therefore encouraging state DOTs to gain experience with the requirements of the procedures and analysis tools for Balanced Mixture Design (BMD). The main objective of this study is to evaluate fatigue cracking on three INDOT mainline pavement projects that have asphalt mixtures designed by the Superpave 5 mixture design, and to better understand the fundamental engineering testing capabilities of the AMPT. A total of four Superpave 5 asphalt mixtures were collected and tested from the three projects. The viscoelastic characteristics and fatigue behavior of plant-mixed, laboratory compacted (PMLC), laboratory-mixed, laboratory compacted (LMLC), and plant-mixed, field compacted (PMFC) specimens were assessed according to the AASHTO TP-132 and AASHTO TP-133 test methods. Two AMPT machines (IPC Controls and PaveTest) were used to conduct the dynamic modulus tests, while all fatigue tests were performed using a PaveTest AMPT. The raw data were analyzed using the FlexMAT software. The dynamic modulus and cyclic fatigue test results indicate that AMPT testing can be used to effectively evaluate INDOT asphalt mixtures during the mixture design and production phases. However, to do so, detailed planning and effective training are needed to help ensure the successful completion of AMPT testing.
2
Mizrach, Amos, Michal Mazor, Amots Hetzroni, Joseph Grinshpun, Richard Mankin, Dennis Shuman, Nancy Epsky, and Robert Heath. Male Song as a Tool for Trapping Female Medflies. United States Department of Agriculture, December 2002. http://dx.doi.org/10.32747/2002.7586535.bard.
Full textAbstract:
This interdisciplinaray work combines expertise in engineering and entomology in Israel and the US, to develop an acoustic trap for mate-seeking female medflies. Medflies are among the world's most economically harmful pests, and monitoring and control efforts cost about $800 million each year in Israel and the US. Efficient traps are vitally important tools for medfly quarantine and pest management activities; they are needed for early detection, for predicting dispersal patterns and for estimating medfly abundance within infested regions. Early detection facilitates rapid response to invasions, in order to contain them. Prediction of dispersal patterns facilitates preemptive action, and estimates of the pests' abundance lead to quantification of medfly infestations and control efforts. Although olfactory attractants and traps exist for capturing male and mated female medflies, there are still no satisfactorily efficient means to attract and trap virgin and remating females (a significant and dangerous segment of the population). We proposed to explore the largely ignored mechanism of female attraction to male song that the flies use in courtship. The potential of such an approach is indicated by studies under this project. Our research involved the identification, isolation, and augmentation of the most attractive components of male medfly songs and the use of these components in the design and testing of traps incorporating acoustic lures. The project combined expertise in acoustic engineering and instrumentation, fruit fly behavior, and integrated pest management. The BARD support was provided for 1 year to enable proof-of-concept studies, aimed to determine: 1) whether mate-seeking female medflies are attracted to male songs; and 2) over what distance such attraction works. Male medfly calling song was recorded during courtship. Multiple acoustic components of male song were examined and tested for synergism with substrate vibrations produced by various surfaces, plates and loudspeakers, with natural and artificial sound playbacks. A speaker-funnel system was developed that focused the playback signal to reproduce as closely as possible the near-field spatial characteristics of the sounds produced by individual males. In initial studies, the system was tasted by observing the behavior of females while the speaker system played songs at various intensities. Through morning and early afternoon periods of peak sexual activity, virgin female medflies landed on a sheet of filter paper at the funnel outlet and stayed longer during broadcasting than during the silent part of the cycle. In later studies, females were captured on sticky paper at the funnel outlet. The mean capture rates were 67 and 44%, respectively, during sound emission and silent control periods. The findings confirmed that female trapping was improved if a male calling song was played. The second stage of the research focused on estimating the trapping range. Initial results indicated that the range possibly extended to 70 cm, but additional, verification tests remain to be conducted. Further studies are planned also to consider effects of combining acoustic and pheromonal cues.