Test Arrangement Research Articles

Fracture Mechanical Characterization of Adhesively Bonded Wood-Ceramic Interfaces for Mode I Loading

Abstract This study introduces a novel approach for investigating the fracture behavior and technical quality of adhesively bonded wood-ceramic interfaces for Mode I loading. For that, a special test arrangement originally used for quasi-brittle materials was applied. The key benefit of this innovative concept is the ability to describe postcracking behavior that is due to stable and steady recording of load-displacement diagrams. This is a big benefit over common practice techniques from both a mechanical and fracture mechanical point of view. The reason for this is that the quasi-brittle material’s nature of unstable cracking comes into place when the test setup is not stiff enough. Another reason to apply fracture mechanics over continuum mechanics is the ability to identify quantitative parameters that describe the softening process in terms of fracture energy. This is a great benefit over stress-based concepts, such as the stress intensity approach (K-concept), which is not appropriate for adhesively bonded multimaterial interfaces. To demonstrate this new approach, bonded wood-ceramic composites were investigated using four different industrial adhesives from Sika AG (Baar, Switzerland) and Murexin (Wiener Neustadt, Austria). The findings indicated interesting relationships between adhesive bonding strength and crack growth resistance when it comes to changing the material of one bonding partner from wood to ceramic. Polyurethane-based adhesives especially show the highest potential of bonding power and fracture resistance when Mode I loading is applied. Furthermore, acrylate-based adhesives are capable of high improvement gains of both mechanical and fracture mechanical parameters when adhesively bonded wood-ceramic interfaces are investigated. This is a remarkable effect and should be part of future investigations by also incorporating the economical aspects of adhesive selection in terms of benchmarking. Finally, these findings could be used for optimizing the mechanical and chemical properties of hybrid adhesives in the future.

Accelerated Pavement Testing to Evaluate the Reinforcement Effect of Geogrids in Flexible Pavements

This study presents an accelerated pavement testing (APT) to evaluate the reinforcement effect of geogrids in flexible pavements. A full-scale conventional three-layer flexible pavement structure was constructed, and was divided into one unreinforced section and two reinforced sections with base reinforced by geogrids placed at different depth of base course. The testing program was divided into three parts: performance testing, response testing, and forensic evaluations. The performance testing recorded the development of surface permanent deformation with the number of loadings. The falling weight deflectometer (FWD) was employed to investigate deflections and moduli of flexible pavements in the response testing. The excavation of pavements was to further analyze reinforcement mechanisms. Test results demonstrated the benefits of incorporating geogrids in base course in reducing the permanent deformation and improving the modulus of base course. Compared with the unreinforced section, accumulated permanent deformations in the two reinforced sections decreased significantly, with a drop of 13%–37%, and the back-calculated moduli of the reinforced base increased by 58%–78% after APT. It was possible that sufficient permanent deformation was needed for mobilizing geogrids to constrain lateral movements of granular particles, to increase the overall structural behavior of the reinforced base course, and to improve the stress distribution on the subgrade. These interaction mechanisms were also confirmed in the pavement trench. For a pavement system consisting of a thin surface and base layer, the proper placement position of geogrids was at the base–subgrade interface for this test and loading arrangement.

Extrinsic and Intrinsic Mechanical Responses of Confined Indented Thin Films

Confined geometries offer useful and experimentally amenable mechanical testing arrangements in which to study the molecular and micro-structural processes which govern plastic yield in stress environments dominated by hydrostatic pressure over shear. However, the changes to macroscopic stress - strain behaviour that result from switching from an unconfined mode such as uniaxial compression to a confined one are often overlooked and display a surprising level of complexity, even for simple elastic - plastic constitutive models. Here we report a confinement induced strain hardening effect in polystyrene thin films achieved through repeated plastic loading with a cylindrical flat punch whose diameter is many times the initial film thickness. This high aspect ratio combines with constraint provided by film material surrounding the contact to generate a state of confined uniaxial strain in the indented region, rendering the deformation one dimensional. By repeated loading into the plastic domain, we achieve a 66% increase in the confined yield stress, from 0.3 GPa to 0.5 GPa. Through finite element simulation and analytic modelling of the principal stresses and strains, we show that this effect arises not from intrinsic changes to the structure of the material, but rather residual stresses imparted during plastic loading. We contrast this effect with intrinsic changes to glassy thin films such as physical ageing and thermal cross-linking.

Productivity enhancement and cycle time reduction in toyota production system through jishuken activity – Case study

The Toyota Production System (TPS) is a process widely used in manufacturing industries which deals with the waste management in firms. Jishuken is a form of problem solving technique which uses Kaizen combined with a Kaizen blitz, but it involves more than solving a problem. Some of the undesired activities that include non-value added movements, improper work floor arrangement, labour’s activities ends in reduction of productivity rate. For such cases firms seeking ideal results which lasts for long term of period. In our project we implementing the principles of Toyota Production System in the firm by looking the problems involved in each activities by the process called Jishuken. We completed the time study for each processes of the firm and we collected the bottlenecks in each processes by Jishuken. The solutions we proposed are meant to be permanent which yield higher productivity rate when compared to the old setup. Here in our project we increased the productivity rate, and reduced the cycle time and operator’s ideal time. We modified the arrangement of chutes in assembly line and increased the number of chutes, position of the torque gun is fixed, additional arrangements for pre testing of horns– stage before the final testing process to eliminate the number of reworking.

Field Measurements of Vibration on the Car Body-Suspended Equipment for High-Speed Rail Vehicles

The vibrations in the flexible car bodies of the high-speed electric multiple units (EMUs) and their coupling effects with the bogies and other types of equipment vibrating have lead issues for railway operators and gained interest for researchers. Other than a numerical investigation, field measurements on the vibrating characteristics of the car body (CB) and its suspended equipment (CBSE) for a high-speed railway vehicle were performed to elaborate the vibrating characteristics on the CB and its CBSE. In this long-term tracking test, the running stability of vehicle and wheel-rail interaction were also examined with the increase of operation distance (OD), a total of 2,400,000 km. The test configuration and arrangements are introduced first, followed by the data analysis in time and frequency domains. It is seen that the wheelset conicity increases 0.008 per 10,000 km, which increases approximately linearly with the OD from 0.10 to 0.40. Two types of wheel treads, S1002CN and LMB10, have different ranges in conicity and reprofiling cycles. The lateral accelerations on CB in a downward-running case (0.5 g) are much greater than that in upward-running case (0.2 g) corresponding to the vehicle stability differences. The 15 Hz low-pass filtered acceleration on CB experiences a maximum of 0.10 g and an averaged amplitude around 0.05 g, whereas the frequency spectrum has peaks of 0.01 g on CB and 0.1 g on CBSE. It states that an elastic suspension between the CBSE and the CB prevents the high-frequency vibration from the CB.

Consideration to Terminating Condition of Mains Cable for Radiated Emission Measurement Caused by Different Disturbance Sources

Very high frequency (VHF)-line impedance stabilization network (VHF-LISN), which is defined as the termination device for mains cable of equipment under test to specify the input impedance of each line at the mains power supply outlet, can improve correlation between test sites that perform radiated emission measurement. Balanced and unbalanced types of VHF-LISN are currently under proposal with International Special Committee on Radio Interference (CISPR) as a device for prescribing the terminating condition of the power supply cable. Simulation analysis with common mode (CM)/differential mode (DM) signal sources was performed to investigate the emission characteristics with the two types of termination devices under several measurement arrangements that used two-wire and three-wire mains cables. Furthermore, to confirm the validity of the simulation analysis, measurement of a versatile comb-generator-operated by ac mains was performed under the same test arrangement and two types of termination devices. Quasi CM/DM signal from an ac-operated comb generator was injected back into the mains cable of the same comb generator. This article explains how we ascertained the radiated emission characteristics with each termination device, and provides guidance for their appropriate usage.

Developing tension field action of embedded steel plates-Stiffened rebars composite reinforcement within concrete deep beams

For reinforced concrete beams, the shear failure mode is confirmed to occur in disturbed regions rather than in the Bernoulli region where stresses can be computed from the flexure formula. Thus, the provision of such regions with shear deficiencies is of great importance. In this study, a tension field system is suggested to embrace the inevitable concrete compression field originating within disturbed regions. Nine rectangular reinforced concrete beams dominated by disturbed regions are tested to verify the proposed shear reinforcement approach of the tension field concept. In this approach, the thin steel plate is embedded within shear span to resist shear strength in two different modes: with and without enhancement of reinforcement as stiffeners. All specimens were tested for failure using a four-point load testing arrangement. Test results demonstrate the feasibility of using embedded mild thin steel plate with and without ribs of rebars as tension field action against initiated concrete compression field action to upgrade the section shear capacity. As depicted by experimental results, the provided tension field system can remarkably upgrade the post cracking, stiffness, and ultimate shear capacity of the considered concrete beams. The stringer panel model is considered to verify and confirm strength improvement. The numerical solution is considered to investigate the proposed composite reinforcement provided within concrete deep beams using the concrete damaged plasticity model. The numerical investigation succeeded to depict the generation of tension field action within the suggested embedded steel plates–stiffened rebars composite reinforcement.

The gravity load simulator – Re-visited

A review of loading arrangements for lateral buckling tests on pultruded glass fibre reinforced polymer (GFRP) beams is presented. It is suggested that the Gravity Load Simulator (GLS), used for similar tests on steel beams could also be used for lateral buckling tests on GFRP beams and, moreover, it could be analysed and designed using exact calculations rather than the iterative method used more than 50 years ago. This conclusion is demonstrated by re-analysing the old iteratively designed GLS. The exact analysis is then used to analyse and design a new GLS for lateral buckling tests on pultruded GFRP beams. The new GLS was fabricated from aluminium bar and plate and details of its overall dimensions and layout and the types of bearings used in its pin joints are described. Thereafter, the test arrangement and instrumentation used to demonstrate the GLS’s accuracy, i.e. maintaining the horizontal translation of the jack’s base as the GLS sways in the lateral buckling plane, is presented. It is shown that the GLS performs extremely well and its use in laboratory testing is illustrated.

A concept for defining the mixed-mode behaviour of tough epoxy film adhesives by single specimen design

Fracture modes I and II interact in mixed-mode loading conditions, and the interaction is typically taken into account using a mixed-mode fracture criterion. In this work, a concept for defining the criterion is developed through an experimental-numerical simulation analysis. The mixed-mode behaviour for the criterion is tested and analysed with a single specimen design. The design of the specimen simplifies the measurement when complex test arrangements and preparations for various specimen geometries are excluded in practice. Here, the mixed-mode fracture behaviour of the specimen is analysed in detail using digital image correlation (DIC). The DIC data are used in collaboration with a finite element–based crack onset analysis, including the virtual crack closure technique, in order to consider the typical simplifications and their effects on the mixed-mode criterion. As a benchmark case, the fracture criterion is determined for an epoxy film adhesive FM 300-2 using the developed approach. The developed approach was shown to be feasible and effective for defining the mixed-mode fracture criterion. The determined Power law criterion’s exponents were below unity, which points out that the common (presumed) exponent values in the current literature are actually unconservative.

Study on Fast Test and Calculation Method of Integrity Coefficient of Surrounding Rock During Tunnel Construction

In this paper, the need of obtaining the rock integrity index in the rapid classification of surrounding rock during the tunnel construction is briefly described. The conventional rock integrity index is introduced and the rapidity of its test acquisition is analyzed. Based on the design of quick test arrangement for rock integrity coefficient, a method of data acquisition and preprocessing for field test of wave velocity of rock block (body) in face is proposed. For the first time, two calculation models of rock block wave velocity and rock mass wave velocity are put forward, one is the calculation model of asymptote method, the other is the calculation model of trend line method. The principle, calculation process, reliability and adaptability of the two calculation models are analyzed and compared. Finally, the trend line method is proposed as the integrated solution of rock block and rock mass wave velocity. Thus, the rapid acquisition of rock integrity coefficient is realized, which lays the key technical foundation for the rapid classification of surrounding rock and the research and development of equipment system during the tunnel construction period, and finally provides the basis and guidance for the dynamic design and construction of tunnel engineering.

Experimental and parametric studies of SCFs in FRP strengthened tubular T-joints under axially loaded brace

An experimental program was carried out on an axially loaded steel welded tubular T-joint made of circular hollow sections and strengthened with Glass/vinyl ester to study the effect of Glass Fiber Reinforced Polymer (GFRP) material on the Stress Concentration Factors (SCF) at both crown and saddle points on the chord member. Four tests were executed. The first test was performed on the plain joint which served as the reference for comparison, and the remaining three tests were performed on the strengthened joints with various FRP strengthening schemes. The arrangement of tests as well as specimen details together with most pertinent results are discussed. A significant drop in SCF values was observed for the FRP-strengthened T-joint as compared to the SCFs of the corresponding un-strengthened joint. The finite element model of the T-joint specimens were made and verified against the experimental data. Furthermore, extensive numerical analyses comprising of 1188 finite element models were performed to achieve a better understanding of the effect of the FRP parameters as well as the joint’s geometric parameters on the chord's SCFs. Additionally, through nonlinear regression analysis, SCF design equations were proposed for the fatigue design of axially loaded FRP strengthened tubular T-joints.

A Useful Power open Market Solution for Power Investment Strategies using the IEEE 30 Bus System

This article planned the power investment strategies that coordinates the power distribution line loss component with the distribution factors. Improved power investment strategies technique for the entire power market. The online price estimator analyzes transfer breaks down exchange rates dependent on specific instruments at the advancement cost list , which work vigorously to modify offers and agreement the executives, which implies that online vitality exchanging expenditure a ton of cash. The planned approach was tried on the IEEE30 bus test arrangement utilizing MATLAB documents from the MATPOWER reproduction program to break down the vitality stream and perfect vitality stream issues. It is a reenactment device that permits reviews and educators to be handily utilized and adjusted to exhibit the various outcomes between valuing plans. The diverse value parameters are a fundamental game plan in the test arrangement, which is associated with over-burdening, steering, and promote the techno-financial examination of the exchanging theory with the foundation computations completed. accessible online as an extra establishment.

Impact of low (zero) carbon power systems on power system protection: a new evaluation approach based on a flexible modelling and hardware testing platform

This study presents a flexible model and testing arrangement that can be used to mimic the fault infeed characteristics of power electronics converters and evaluate the performance of transmission protection schemes to faults when the system is ‘converter-dominated’. That is sources (e.g. renewables) and infeeds (e.g. HVDC interconnectors) that are interfaced to the main power system via converters. Actual protection relays are injected, in real-time, using the outputs of the various fault simulations. A range of potential protection issues, including slow tripping, erroneous discrimination and non-operation, are illustrated for particular scenarios. The main contributions of the study include knowledge of how different protection schemes may be affected by converter-interfaced sources and guidance on possible solutions to the observed problems. Two solution options are highlighted: changes to the fault detection methods used within relays, and/or defining the fault-response elements of future grid codes (and therefore future converter fault responses) to ensure that existing protection schemes will not be adversely affected in future low-carbon, converter-dominated systems.

Current interruption performance of ultrahigh-pressure nitrogen arc

In this paper, the influence of gas filling pressure on the current interruption performance of different switch configurations with electric arcs burning in nitrogen has been experimentally investigated. A synthetic circuit generating a current of 130 A at 190 Hz is used and the initial rate of rise of recovery voltage just after current zero is varied from 9.8 V/µs to 84.9 V/µs. To evaluate the effect of forced gas flow on current interruption performance, three different test arrangements are investigated: a simple contact configuration with a free-burning arc, a contact and a cylindrical nozzle setup (tube-constricted arc), and finally a self-blast arrangement where the arc is cooled by a gas flow near current zero. In each arrangement, three different filling pressures are mainly studied: 1, 20, and 40 bar, the latter being in the supercritical region. In all cases, the interelectrode gap is fixed at 50 mm. It is observed that the interruption performance deteriorates with increased filling pressure in the absence of forced gas flow. A higher post-arc current is observed for the arcs burning at high filling pressures (i.e. 20 and 40 bar) compared to at atmospheric pressure in cases with no or little forced cooling. On the other hand, a forced gas flow near the current zero reduces the post-arc current and improves the interruption performance also at high filling pressures. Little effect of the supercritical state on the interruption performance of nitrogen is observed. Under the above-mentioned test conditions, the majority of the failures at high filling pressure are observed to be of thermal re-ignition type.

Comparison between the Behaviors of Different Concrete Types in Various Shear Tests

A comparison between three direct shear test specimens of (push-off shear specimens, FIP shear test, and inverted “L” shape shear failure plane) was investigated experimentally and numerically and cast using normal, high and ultra-high-strength concrete with the effect of steel fiber. This paper presents which shear strength analysis settings in which testing operation and arrangement of mold can be performed by the simplest and at the same rate guarantees stable and steady results. Many variables were chosen to investigate its impact on shear test and behavior. These variables are grade of concrete, steel fiber volume fraction, method of testing, type of loading and size of shear failure plane area. A comparison between experimental work and the finite element method offers a powerful and generic tool for studying the behavior of many structures by ANSYS program which can represent many structures. It was found that the inclusion of steel fiber enhances the ultimate shear capacity of the concrete compared to plain concrete and leads to ductile failure method, higher ultimate strength in addition to much enhanced integrity of structure.

Analysis and Research on Vibration Severity of Planetary Shifting Mechanism

The vibration severity indicates the severity of the vibration and is usually expressed by the maximum, average or root mean square value of the displacement, velocity and acceleration that characterize the vibration level. In this paper, based on the calculation of vibration severity, the arrangement of test measuring points, the selection of typical working conditions and the analysis of test results, the vibration severity of planet Shifting mechanism is tested and studied, and the rating is completed according to the relevant evaluation method of national standard, which provides support for the vibration analysis of transmission device and the research and development of planet transmission mechanism.

Potentiodynamic Corrosion Characterization of Hybrid Aluminium Composites for Advanced Engineering Applications

Corrosion characterization of Aluminium composites is a significant study planned for assessing the capability of utilizing the materials for aviation and automobile parts. Aluminium 5083 is a particular class of alloys which is known for its corrosion resistance in extraordinary conditions and is utilized in aerospace components. However, the experimentations on impact of reinforcements, for example, the effect of Silicon carbide and Flyash on corrosion properties of Aluminium 5083 alloys is still in its incipient stage and not much literature is available outlining the corrosion attributes. The present work includes the fabrication of Aluminium 5083 – Silicon carbide – Flyash composites and investigation of the corrosion conduct of these composites. The composites are fabricated by stir casting procedure, considering silicon carbide particulates varied in the scope of 3 wt.% to 9 wt.% at an intermittent intervals of 2 wt.%. The composition of fly ash in the present work is limited to 5 wt. % for restricting the porosity after conducting preliminary trials. The composite materials considered in this research are assessed for corrosion by Potentio-dynamic test, which is accomplished utilizing a test arrangement comprising of five mouth jar with calomel electrode and a working cathode (comprising of the specimen held rigidly with a copper wire and secured with Teflon tape notwithstanding a region of one square centimeter exposed to the electrolyte). The anodic and cathodic potentio-dynamic polarization estimations are acquired as tafel plots in the PC that is interfaced with the test arrangement. The outcomes reveal that the corrosion current (Icorr) increases with the increase in the weight percentage of Silicon carbide in the metal matrix. The electrolyte considered for the potentio-dynamic test is and 1 M HCl (acidic) medium.

Phosgene formation via carbon monoxide and dichlorine reaction over an activated carbon catalyst: Reaction testing arrangements

An apparatus is described to investigate the synthesis of phosgene from the reaction of carbon monoxide and dichlorine over an activated carbon catalyst. Infrared spectroscopy and UV–vis absorption spectroscopy are used to identify and quantify reagents and products. The reaction is operated with an excess of CO in order to enable complete chlorine conversion at elevated temperatures. The reaction profile is examined over the temperature range of 300−445 K, with a phosgene selectivity of 100 % observed at all temperatures. An isosbestic point in the UV–vis spectrum is observed at 272 nm, indicating that the dichlorine and the phosgene are in equilibrium. Examination of the phosgene formation rate as a function of space time and catalyst size fraction at 323 K establishes that, under the described conditions, the reaction is operating under chemical control in the absence of mass transfer restrictions.

Comparison study for some biomechanical and physiological variables as a indicates for passing admission tests for the physical education department at AL Qaseem and Port Said University

this research aims to determine the calories required to pass the admission tests in the Department of Physical Education and Movement Science, as well as the calories required to pass the admission tests in the colleges of physical education in the Arab Republic of Egypt and the Kingdom of Saudi Arabia and determining the amount of work spent, energy, and power spent during the performance of the tests and most important ware There is no difference in the arrangement of physical tests according to the calorie consumption between Egypt and Saudi Arabia except inability and agility there was a change between them. There is no difference in the arrangement of physical tests according to the work done and the energy spent, except inability and agility, there was a change between them.There is a difference in the arrangement of physical tests according to the ability made between Egypt and the Kingdom

The Impact of Environmental Factors on the Thermal Characteristic of a Lithium–ion Battery

To draw reliable conclusions about the thermal characteristic of or a preferential cooling strategy for a lithium–ion battery, the correct set of thermal input parameters and a detailed battery layout is crucial. In our previous work, an electrochemical model for a commercially-available, 40 Ah prismatic lithium–ion battery was validated under heuristic temperature dependence. In this work the validated electrochemical model is coupled to a spatially resolved, three dimensional (3D), thermal model of the same battery to evaluate the thermal characteristics, i.e., thermal barriers and preferential heat rejection patterns, within common environment layouts. We discuss to which extent the knowledge of the batteries’ interior layout can be constructively used for the design of an exterior battery thermal management. It is found from the study results that: (1) Increasing the current rate without considering an increased heat removal flux at natural convection at higher temperatures will lead to increased model deviations; (2) Centralized fan air-cooling within a climate chamber in a multi cell test arrangement can lead to significantly different thermal characteristics at each battery cell; (3) Increasing the interfacial surface area, at which preferential battery interior and exterior heat rejection match, can significantly lower the temperature rise and inhomogeneity within the electrode stack and increase the batteries’ lifespan.