Value Of Applied Load Research Articles

Determination of “tribological performance working fields” for pure PEEK and PEEK composites under dry sliding conditions

Poly-ether-ether-ketone (PEEK) and PEEK composites are widely used polymers in many engineering applications where dry sliding is required. In this study, the influence of sliding velocity and applied load values on the friction and wear behavior of pure PEEK, 30 wt% glass fiber reinforced PEEK (PEEK-30GF), 30 wt% carbon fiber reinforced PEEK (PEEK-30CF) and 10 wt% carbon fiber+10 wt%graphite +10 wt%poly-tetra-fluoro-ethylene (PTFE) filled PEEK (ie. High (H) pressure (P) and velocity (V) resistant PEEK (PEEK-HPV)) composites rubbing against AISI 304 stainless steel disc was investigated. The experiments were carried out at room temperature under dry sliding conditions in a pin-on-disc wear rig. The applied loads ranged from 30 to 250 N, while the sliding velocities ranged from 1.0 to 4.0 m/s. At these load and velocity ranges, the friction coefficient-wear rate relationship of pure PEEK and composites was established and evaluated. In addition, the operating load-velocity limits of each material were determined and stated. The lowest coefficient of friction and wear rate were obtained in PEEK-HPV, PEEK-30CF, PEEK-30GF composites and pure PEEK polymer, respectively. In addition, it was observed that the coefficient of friction (CoF) decreased and the specific wear rate (SWR) increased with the increase in sliding velocity and applied load in all PEEK materials. The wear rate values of PEEK-HPV and PEEK-30%CF composites are in the range of 10−7 - 10−6 (mm3/Nm), while the wear rate values of pure PEEK and PEEK-30%GF are in the range of 10−6 - 10−5 (mm3/Nm). It was determined that carbon fiber, graphite and PTFE additives added to PEEK polymer as hybrid were very effective in reducing the wear rate of PEEK composite (PEEK-HPV). An adhesive wear mechanism was observed in PEEK-HPV and PEEK-30CF composites both at low load and velocity values and at high load and velocity values.

SISTEM MONITORING KWH METER DIGITAL BERBASIS IOT PADA LABORATORIUM PERALATAN MEDIS

The educational process, which is supported by adequate laboratory facilities and infrastructure, will produce professional higher education tri-dharma outputs, both for students and lecturers. The Medical Equipment Laboratory is a place where experimental studies with various equipment and devices, analyses, and observations are carried out. The amount of electrical energy used by a university can be measured using an electric energy meter, namely the kWh meter, but the university cannot monitor which building or room uses the most electrical energy because it only knows the amount of power used each month. Given these problems, a digital kWh Meter monitoring tool based on the Internet of Things (IoT) is designed to measure the amount of current, voltage, power, and costs that must be incurred while using medical equipment and can then be monitored in real time using the Blynk application as the server. The implementation system for monitoring the kwh meter using the PZEM-004T sensor has a very good accuracy rate of 99.52% for measuring voltage and 99.87% for measuring current on medical equipment in the medical equipment laboratory at the PGRI Yogyakarta University. It was found that the greater the applied load value, the more the impact on data outputs such as current and voltage would affect the size of the monthly electricity bill. The monitoring system can be carried out within a radius of 20 meters as long as the smartphone is connected to a WiFi connection. Monitoring activities and electrical device control activities can be carried out.

Evaluation of the Foundation Beds Liquidation by Using Soil Modeling for El-Burullus Power Plant Area, Kafr El-Sheikh, Egypt

In this study, the soil has been numerically modeled as the Mohr-Columb model because it is simple to capture essential features of soil behavior. Plaxis 2D software program has been used for modeling. The dynamic analyses depend on some data, such as grain size gradation for materials, stiffness and water level. This data has been used in the calculation process. Simple applications have been chosen to calculate the relations. The program computes entered data automatically. Earthquakes result in dynamic loading on soil which has a significant effect on the soil properties. The model is formed of five soil layers. Sands and mud deposits covered the area and Delta also. Some of the study results can be estimated by using the modeling method. The applied load value is 100 kN/m2. The amplification factor (S %) to the soil in the study area is 108 % when soil is without the foundation load and 150 % when soil with foundation load. Thus, the soil is classified as type – D (Moderate) and no liquefaction is expected in the results, but subduction or landslide, so piling foundations are recommended within the area of study. As well, numerical modeling is recommended in several locations in Egypt to obtain suitable areas for the foundation constructions.

Comparison of Punching Shear Behaviour of Two-Way Concrete Slab Reinforced with CFRP Grid and Steel Bars

Two punching shear failure tests of two-way concrete slab reinforced by CFRP grid and HRB 400 steel were studied in this paper. The reinforcement ratio of slab reinforced with CFRP grid and HRB400 is 0.33% and 0.37 respectively. The upper and lower surfaces of the concrete slab’s tensile and compressive strains, the reinforcement strains, the load deflection of the slabs, and the applied load value were analyzed. The results show that under approximately the same reinforcement ratio, the concrete slab reinforced with CFRP grid has higher bearing capacity. Both slab failure formed with punching cones, the punching cone angle of CFRP grid slab is 24.1°, which is far less than 38° for reinforced concrete slabs. The tests results indicated that there is a cooperative between longitudinal and transverse limb of CFRP grid.

A laser-induced dual ultrasonic wave method for noncontact load monitoring of pillar porcelain insulators

In this paper, a noncontact load monitoring method based on laser-induced synchronous ultrasonic surface wave and air wave is presented to improve the accuracy of load measurement on pillar porcelain insulator. In order to eliminate the measurement error caused by insulator deformation, a correction algorithm for surface wave velocity calculation is established by introducing the air wave propagation time. An experimental setup of the load measurement system for pillar porcelain insulators based on laser-induced dual ultrasonic waves was assembled. A load calibration experiment and load detection experiment were carried out under various bending and torsional loads. The results showed that the proposed method is effective to solve the problem of the surface wave propagation time changing abruptly, greatly increasing the accuracy of load measurement. In the monitoring experiments, the relative error between the calculated load value and the actual applied load value was small, the average measurement error of the bending load was 16.20%, and the average measurement error of the torsional load was 11.38%. This proved that the measurement of the insulator load value using a laser ultrasonic surface wave is more precise than the traditional methods, making it more suitable for engineering inspection.

Investigation of type 1 and type 2 fuzzy logic controllers performance: application of speed control of BLDC motor

In this paper, a simulation study enhanced to model that the speed control of brushless direct current (BLDC) motors used in electric vehicles with intelligent control methods. The simulation study was prepared in Matlab/Simulink environment. The first control method is Type-1 fuzzy logic control (T1FLC), and the second control method is the Intermittent Type-2 fuzzy logic control (IT2FLC) model. Membership functions for different membership numbers have been created for both types of FLC models. These are 3×3, 5×5, 7×7. Control methods are prepared in Matlab/M-file environment. The model is defined as the input variable of the error, which is the difference between the reference speed and the motor speed, and the output variable of the Pulse Width Modulation (PWM) signal applied to the motor. The simulation study maintains the speed of the BLDC motor up to the reference speed with T1FLC and IT2FLC controllers, depending on the reference speed and applied load values. Depending on the number of different memberships, the effects of controller performances on the control of motor speed have been observed. The graphs and findings of the experiment are shown in the results and discussion section.

Design Approach for Eccentrically Loaded Reinforced Concrete Sections

The behavior of eccentrically loaded reinforced concrete sections depends on both the eccentricity and load value. The type of failure can be determined according to the eccentricity-thickness ratio and the applied load value. Interaction diagrams can be used for designing eccentrically loaded section, but the section dimensions are required to use these diagrams. According to the section dimensions and the load value, the type of failure and the required reinforcement can be determined from the interaction diagrams. Most design codes controls the design process to ensure ductile failure. But according to the design procedures of interaction diagrams, the failure type can’t be controlled simply. This paper aims at finding a design procedure for eccentrically loaded reinforced concrete sections that enable the designer to simply control the design process and the failure mode. The proposed design approach makes the design process more direct and simplified.

Particle image velocimetry and digital image correlation for determining the elasticity modulus in wood

Several non-destructive testing techniques have been improved and tested in recent years. The non-destructive testing techniques using particle image velocimetry (PIV) and digital image correlation (DIC) differ from conventional testing techniques, as they allow making measurements indirectly. In this study, the elastic modulus in wood beams of Eucalyptus grandis and Pinus oocarpa were determined using PIV and DIC. The application of PIV and DIC techniques occurred during the static bending tests, when the displacements were also measured by the conventional method. The applied load values allowed calculating the elasticity modulus. In all regions of analysis, the mean values of the elasticity modulus found by the DIC, PIV and conventional method are statistically equivalent. It is concluded that the PIV and DIC testing techniques can be used to determine mechanical properties of wood.

Effect of the temperature variation on the hardness and microstructure of TiSiNO coatings obtained by sputtering

Titanium-Silicon Oxynitride (TiSiNO) coatings were synthetized by reactive co-sputtering technique on stainless steel 304 substrates varying the substrate temperature during the deposition. Two targets were used simultaneously, the first one of Ti on a DC source at 100 W and the second was a Ti-Si-O target on a pulsing RF source at 180 W. X-ray diffraction identified three crystalline phases: titanium nitride (TiN), titanium oxide (TiO) and silicon oxide (SiO2), where the SiO2 phase presented compressive stresses at low temperatures and tension stresses at higher temperatures, along with a change in the preferential orientation. The coating obtained at 200 °C showed the higher hardness value of 14.8 GPa, attributed to a lower grain size and high compressive stress. Finally, all coatings presented high fracture toughness, since the was a lack of any type of crack for all applied load values.

Tribological Properties of Nanoclay Reinforced Polyamide‐6/Polypropylene Blend

In this study, the tribological performance of polyamide‐6 (PA‐6), polypropylene (PP), polyamide‐6/polypropylene (PA‐6/PP) polymer blend, and nanoclay reinforced polyamide‐6/polypropylene composite are investigated. Nanoclay reinforced polymer composite is produced by melt compounding using co‐rotating twin screw extruder followed by injection moulding. Tribological studies are carried out using a pin‐on‐stainless steel disc configuration under dry sliding conditions. Tribological tests are carried out at sliding speed of 0.5 m s−1 and applied load values of 25, 50,100, 150 N. The friction coefficient and specific wear rate values are obtained and evaluated. The results show that the addition of nanoclay into the PA‐6/PP polymer blend reduced their coefficient of friction and specific wear rate values. The lowest coefficient of friction and specific wear rate values are for nanoclay reinforced PA‐6/PP blend. The highest coefficient of friction and specific wear rate values are for PA‐6 polymer.

Określenie zakresu oddziaływania obciążenia w statycznych i dynamicznych badaniach podłoża przy zastosowaniu płyty sztywnej

Soil bearing capacity and compactness testing by rigid plates is commonly used during ground investigations and work quality control on most sites where enclosed and right-of-way structures are being built. Typically, the VSS (static plate bearing) test apparatus is used for this purpose. In recent years LFG falling weight deflectometers (dynamic plate load tests) have been increasingly used on building sites. This paper presents the theoretical bases relating to load testing by rigid plates. Several numerical calculations were made for selected soils, presenting the load distribution, corresponding to the range of the above tests in the subgrade. The type and state of soil as well as the applied load values have been confirmed to have a decisive bearing influence on the load action range. The assumption of the constant measuring range for static plate bearing tests (amounting to about 2-3 plate diameters) and for dynamic plate load tests has not been proved by the numerical calculations based on the theory of rigid foundations.

Small punch and uniaxial creep fracture behaviours of modified SUS304H steel at various temperatures

Commercial austenitic stainless steel SUS304H with small amount of vanadium addition was used in this study. Small punch (SP) creep and uniaxial tensile creep tests were conducted at 650, 700, and 750 °C to measure creep lives and the minimum displacement rates or the minimum creep strain rates. The measured parameters were compared between the two test methods, seeking empirical relationships among the parameters using Larson-Miller Parameter and Monkman-Grant relation. Magnitude of the applied stress (MPa) in the uniaxial tensile creep test was approximately equal to the applied load value (N) in the SP creep test at all test temperatures. It was shown that during the creep deformation of the SP creep specimen, crack initiation and accompanying crack growth occur simultaneously. Competing failure mechanisms of creep deformation and crack growth may affect the SP creep life and consequently determine the proportionality function, α, in the relation between the SP load and the tensile creep rupture stress in creep tests.

Comparison of the tribological and mechanical performance for nano and micro filler epoxy composites

Abstract In this investigation, the tribological and mechanical performance of 10 wt.-% filled nano and micro epoxy composites were studied and compared. Nano fillers are Al2O3, TiO2 and clay and micro fillers are Al2O3, TiO2 and fly ash. Mechanical and wear tests were carried out. Wear tests were performed on pin-on-disc arrangement. Test conditions were 5, 10, 15 N applied load values, sliding speed of 0.8 m × s−1, 2000 m sliding distance under dry atmospheric conditions. The results show that the mechanical and tribological performance of micro filler filled epoxy composites are better than those of the nano filler filled composites.

Investigation on Mechanical and Tribological Behaviors of PA6 and Graphite-Reinforced PA6 Polymer Composites

In this paper, the effects of adding graphite on the mechanical and tribological properties of polyamide 6 (PA6)-based composites were investigated. PA6 was reinforced with graphite by varying the weight proportions. The test specimens for mechanical and tribological experiments were molded in an injection molding machine. The mechanical properties of PA6 and graphite-reinforced PA6 polymer composites were investigated in terms of tensile strength, impact and hardness tests. The PA6 composite containing 20 wt% graphite revealed the better mechanical behaviors. The wear test was observed by using a pin-on-disk machine under dry sliding conditions at 5, 10, 20 and 30 N applied load values and sliding speed of 1000, 1500 and 2000 rpm. Scanning electron microscopy was utilized to examine the worn surfaces microstructure and wear mechanisms before and after the tribological test. The results showed that the reinforced PA6 polymer composites with 20 wt% graphite enhanced the best tribological behavior. The addition of graphite enhances the life condition of normal PA6 to a greater extent. Also, this composite exhibits stronger interfacial bonding characteristics with improved wear resistance.

Investigation of debonding propagation in aluminum/composite joints under fatigue loading

In this paper, Fracture Mechanics is used to predict debonding propagation in adhesive joint between aluminum and composite plates. Three types of loadings (λ = 0, λ = 0.5, and λ = 1 when λ is the ratio of lateral to in-plane loading) and two types of glass–epoxy composite sequences: [0/90]2s and [0/45/−45/90]s are considered for the composite plate and their results are compared. It was seen that generally the cases with stacking sequence of [0/45/−45/90]s have much shorter lives than cases with [0/90]2s. It was also seen that in cases with λ = 0, the ends of the debonding front propagates forward more than its middle, while in cases with λ = 0.5 or λ = 1 it is vice versa. Moreover, regardless of value of λ, the difference between the debonding propagations of the ends and the middle of the debonding front is very close in cases λ = 0.5 and λ = 1. Another main conclusion was that the non-dimensionalized debonding front profile is almost independent of sequence type or the applied load value.

Thermal, mechanical and tribological performance of polymer composites rubbed against polymer composites in application in electrical contact breakers

In this investigation, the thermal, mechanical properties and tribological performance of polyamide 6 composites filled up to 30 wt% mica is studied. The dry friction and wear tests of 30 wt% mica-filled polyamide 6 rubbed against 30 wt% mica-filled polyamide 6 and 30% glass fiber reinforced polyamide 6 polymer composite's discs were carried using a pin-on-disc test rig. Test's conditions were room temperature, applied load values of 20 N, 30 N and 40 N and at 0.5 m/s sliding speed. The results show an announced influence on mica content on the coefficient of friction and specific wear rate values of polyamide 6 composites. The results also show the influence of mica content on the mechanical properties, glassy transient temperature Tg and the melting temperature Tm of polyamide 6 polymer.

Examination at a Material and Structural Level of the Fatigue Life of Beams Strengthened with Mineral or Epoxy Bonded FRPs: The State of the Art

This paper presents a state of the art review of different material combinations and applications of mineral-based and epoxy-based bonded Fiber Reinforced Polymers (FRP), used for the strengthening of concrete structures subjected to fatigue loading. In this review, models of the fatigue life at the material and structural level are presented. This study examines the mechanical behavior of the FRP-material, surface bonding behavior and concrete beams strengthened under fatigue loading with different types of FRP-systems. The parameters that are investigated are applied load value, time dependent effects, type of strengthened structures (shear, flexural or combined) and the configuration of sheets or plates. The building codes and researchers' recommendations are also discussed. As a result of this review, the reader will obtains an overview of suitable materials and methods for strengthening structures subjected to fatigue loading by referring to the estimated fatigue life of material and strengthening structures at various applied stress levels.

Tribological Performance of Polyetheretherketone and its Composites under Water Environment

SummaryIn this study, the influence of lubrication on the friction and wear performance of pure polyetheretherketone (PEEK), 30 wt.‐% carbon fiber and 30 wt.‐% glass fibers reinforced PEEK composite is investigated. The sliding experiments were carried out on a polymer pin‐on‐ a steel disc arrangement. Wear tests were resumed at room temperature under 50 to 200N loads and at 0.40 and 1.2 m/s sliding speed. The results show the large influence of water lubricant on the tribological performance of PEEK and PEEK composites. Furthermore, the coefficient of friction for PEEK increases by the increase in applied load value but this influence is not significant for PEEK composites. Generally, for the range of load and speed values for this study, the coefficient of friction using water lubricant registered lower values than that of the dry condition. Finally, the specific wear rates for PEEK + 30 wt%CF and PEEK + 30 wt%GFR composite under water lubricated conditions are all mostly in the order of 10−15 m2/N.

Tribological performance of polymer composites used in electrical engineering applications

Sliding wear performance of 20% mica-filled polyamide 6 (PA6 + 20% mica) and 20% short glass fibre-reinforced polysulphone (PSU + 20 GFR) polymer composites used in electrical applications were investigated using a pin-on-disc wear test apparatus. Two different disc materials were used in this study. These are AISI 316 L stainless steel and 30% glass fibre-reinforced polyphenylenesulphide (PPS + 30%GFR) polymer composite. Wear test was carried out at 10, 20 and 30 N applied load values and 0·5 m/s sliding speed and at ambient temperature and humidity. Different combinations of rubbing surfaces were examined and friction coefficient and specific wear rate values were obtained and compared. For two material combinations used in this investigation, the coefficient of friction shows insignificant sensitivity to applied load values and large sensitivity to material combinations. For specific wear rate, PA6 + 20% mica composite has shown insensitivity to change in load, speed and materials combination while PSU + 20% glass fibre composite has shown high sensitivity to the change in load and material combinations. The friction coefficient of PA6 + 20% mica and PSU + 20 glass fibre rubbing against the AISI 4140 steel disc is between 0·35 and 0·40. In rubbing against PPS + 30% glass fibre their values were between 0·25 and 0·30. Specific wear rate for PA6 + 20% mica and PSU + 20% glass fibre composites are in the order of 10 − 13 to 10 − 14 m2/N. Finally, the wear mechanisms are a combination of adhesive and abrasive wear processes. In terms of application, especially in electrical systems, a substantial contribution was provided to extend switch life. Thus, besides robustness, this also ensured safety for the system and the users against undesirable situations.

Comparison of tribological performance of PEEK, UHMWPE, glass fiber reinforced PTFE and PTFE reinforced PEI composite materials under dry and lubricated conditions

Abstract In this study, the tribological performance of poly-ether-ketone (PEEK), ultrahigh molecular weight polyethylene (UHMWPE), glass fiber reinforced poly-tetra-fluoro-ethylene (PTFE) and PTFE reinforced poly-ether-imide (PEI) composite materials, under dry and lubricated conditions, were compared and evaluated. Wear tests were carried out on a pin-disc arrangement and under 50, 100 and 150 N applied loads and 0.5 m/s sliding speed conditions. The results show that the coefficient of friction and specific wear rates for these materials decreases with the increase in applied load values. Finally, the wear rates for PEEK, UHMWPE polymers, PTFE+20% glass fiber reinforced (GFR) and PEI+10% PTFE composites under dry and lubricated conditions are in the order of 10-14 and 10-15, respectively. The results suggested that it is convenient to use PTFE+20% GFR composites for machine components with low processing and product costs.