Cylindrical Test Research Articles

Tensile Notch Sensitivity of Additively Manufactured IN 625 Superalloy

The notch sensitivity of additively manufactured IN 625 superalloy produces by laser powder bed fusion (LPBF) has been investigated by tensile testing of cylindrical test pieces. Smooth and V-notched test pieces with four different radii were tested both in as-built state and after a stress relief heat treatment for 1 h at 900 °C. Regardless of the notch root radius, the investigated alloy exhibits notch strength ratios higher than unity in both as-built and in stress-relieved states, showing that the additive manufactured IN 625 alloy is not prone to brittleness induced by the presence of V-notches. Higher values of notch strength ratios were recorded for the as-built material as a result of the higher internal stress level induced by the manufacturing process. Due to the higher triaxiality of stresses induced by notches, for both as-built and stress-relieved states, the proof strength of the notched test pieces is even higher than the tensile strength of the smooth test pieces tested in the same conditions. SEM fractographic analysis revealed a mixed mode of ductile and brittle fracture morphology of the V-notched specimens regardless the notch root radius. A more dominant ductile mode of fracture was encountered for stress-relieved test pieces than in the case of the as-built state. However, future research is needed to better understand the influence of notches on additive manufactured IN 625 alloy behaviour under more complex stresses.

Identification of strain localization-induced failure in hot-rolled steel sheets: A hybrid numerical–experimental approach to the virtual forming limit test

A coupled numerical–experimental inverse calibration approach was implemented and systematically validated to evaluate the formability of high-strength, hot-rolled, hyper-burring (HB780) steel sheets and dual-phase (DP780) steel sheets. The proposed methodology featured the determination of hardening behavior beyond the uniform elongation limit at large strain and shapes of 3-D, non-quadratic yield functions: Hosford and Yoshida models. To accurately identify the 3-D yield functions and directly monitor the strain localizations of hemispherical domes for the virtual numerical forming limit analyses, stretching tests were recommended for the investigated hot-rolled sheets. The modeling procedure was evaluated by comparing the forming limits of the stretching tests’ various sample widths to those of the experiments, which confirmed the validity of the identified constitutive model parameters by predicting the localized failure strains and punch force–displacement curves under different deformation modes. For the purpose of validation, simulations and experiments of cylindrical circular cup drawing tests were performed. The proposed numerical procedure could predict the profiles of eared cups, locations of fracture, and drawing limit ratios of the two hot-rolled sheets without the input of the forming limit diagram when proper calibrations of the 3-D, non-quadratic, anisotropic yield function and strain hardening at large strains were guaranteed.

Strength and abrasive properties of andesite: relationships between strength parameters measured on cylindrical test specimens and micro-Deval values\u2014a tool for durability assessment

Aggregates are necessary materials for the construction industry. Owing to their favourable properties, andesites are frequently used rock materials; hence, the investigation of their mechanical and aggregate properties has great significance. This paper introduces the analyses of 13 Hungarian andesite lithotypes. The samples were collected from six andesite quarries in Hungary. Cylindrical specimens and aggregate samples with 10.0/14.0-mm-sized grains were made from rock blocks. The specimens were tested in dry, water-saturated and freeze–thaw subjected conditions. Bulk density, uniaxial compressive strength, modulus of elasticity, indirect tensile strength and water absorption were measured. The abrasion resistance was tested by micro-Deval tests. The flakiness indexes of the samples were also measured. The data set of the laboratory test results provided input for further, one- and two-variable statistical analyses. According to the test results, there is no significant difference between the strength parameters measured in water-saturated and in freeze–thaw subjected conditions. The correlation and regression analyses revealed relationships between some rock mechanical parameters, as well as between micro-Deval coefficient and uniaxial compressive strength.

Taguchi optimization of surface roughness in grinding of cryogenically treated AISI 5140 steel

Abstract This study investigated the performance of the grinding parameters used in the cylindrical grinding process of AISI 5140 steel and identified optimum grinding conditions via the Taguchi optimization method. Experiments were carried out via the L18 orthogonal array. Control factors for optimum surface roughness (Ra) values were determined by using the Taguchi method. Two different grinding wheels (SiC and Al2O3), three different cryogenic samples (CHT, DCTT-15 and DCTT-30) and depth of cuts (100, 200 and 300 μm) were selected as control factors. The cylindrical grinding test results showed that optimal Ra values were obtained on specimens cryogenically treated for 30 h (DCTT-30). Linear and quadratic regression analyses were conducted for the experimental results. The correlation coefficients (R2) were found to be 0.957 and 0.993 with linear and quadratic regression models, respectively. Finally, confirmation tests were performed and showed that the optimization had been successfully implemented.

Modeling and Numerical Simulation of the Effect of Temperature on the LCF Behaviour of a CuCrZr Alloy Specimen

The main originality of this work consists in investigating low cycle fatigue of cylindrical test piece with wings under imposed constraint and for the temperature 20°c, 200°c, 400°c. Based on a combination between the fatigue parameter of Jiang-Sehitoglu and the relationship of Coffin-Manson, a numerical model for the prediction of the number of cycles at break. It was found that the CuCrZr cylindrical test piece showed a reduction in fatigue life with increasing temperature.

Instrumented cylindrical punch indentation of solid nitrogen at 30–40 K

In support of NASA’s Triton Hopper project, mechanical response data for solid nitrogen are needed for concept validation and development. Available mechanical properties data is sparse with only three known indentation measurements existing between 30 and 40 K. To generate more data, a custom instrumented hardness tester was developed to interface with a cryostat. The system was used to conduct cylindrical punch indentation testing at Triton-relevant thermodynamic conditions. Pressure versus displacement curves and hardness values were obtained. In the experiments the hardness ranged between about 2 kg/mm2 and 0.5 kg/mm2 in the aforementioned temperature range. A suspected brittle fracture is observed at lower temperatures in the range.

Reflected shock-initiated ignition probed via simultaneous lateral and endwall high-speed imaging with a transparent, cylindrical test-section

A TRAnsparent cylindrical (TRAC) shock tube test section has been developed to explore the ignition structure behind reflected shockwaves via simultaneous lateral and endwall high-speed imaging using three fuel/oxidizer mixtures: 0.1% n-C7H16/1.10% O2/4.14% N2/94.66% Ar, 0.1% iC8H18/1.25% O2/4.69% N2/93.96% Ar, and 5% CH4/10% O2/85% CO2. During mild ignition, the first exothermic centers were located outside of the observable test section. It is shown that with increasing temperature the far-wall ignition events move closer to the endwall, until a strong ignition is achieved. The temperature gradients that promote mild ignition were quantified and were found to have a slight dependence on fuel with the RMS temperature gradients being 0.80% for n-heptane and 1.07% for isooctane. The impact of temperature gradients on metrics used to improve kinetic models, such as species time histories, is noteworthy. From this temperature gradient, an experimental correlation is provided to estimate the transition temperature from mild to strong ignition for a mixture. The effect of diagnostic location in non-homogeneous reactions is quantified in reference to ignition delay. The unique and insightful perspective on the ignition process under heavy shock bifurcation is also discussed.

Assessment of uniformity of microwave-based heating profiles generated by solid-state and magnetron systems using various shapes of test samples

In a previous paper, we established a test routine and found in cuboid gellan test samples containing Maillard reactive agents that the solid-state system yields a more uniform heating profile. This was attributed to a more uniform microwave energy distribution profile in the solid-state oven cavity. In this work, we aim at determining the heating profile in various test sample shapes exposed to classical magnetron and innovative solid-state microwave systems. Therefore, we assessed the uniformity of heat processing between both solid-state and magnetron microwave generators using other test sample shapes of spherical and cylindrical forms and compare the results with the test samples with cuboid shape. The comparison confirms that the solid-state microwave system also results in more uniform heating of the cylindrical test samples like in the cuboid test sample, while the spherically-shaped test sample this was not the case. The explanation most likely is that the focus of microwave energy in the center of the spherical sample is more dominating such that the external microwave energy distribution is less decisive for a uniform heating profile. In other words, the possibility of distinguishing the differences between the solid-state and magnetron microwave generators and comparing the uniformity of their thermal processing requires a certain sample shape. Spherical samples are less suitable, because of the focusing of energy towards the sample center and difference between the systems can be determined much less sensitively compared to other shapes. These results contribute to understand microwave heating systems better and provide guidance in product development in terms of shapes most suitable to achieve heating profiles with reduced issues related to hot/cold spots in the product.

PENGARUH KONDISI MATERIAL DENGAN AKTIVATOR POTASSIUM PADA BETON GEOPOLYMER DARI LIMBAH B3 FLY ASH BATUBARA TERHADAP KUAT TEKAN

Pada umumnya beton dikenal material yang tersusun dari komposisi utama batuan (aggregat) kasar, pasir, air dan semen. Karena persediaan semen yang semakin berkurang, berbagai penelitian telah dilakukan untuk mencari material yang ramah lingkungan sebagai pengganti semen. Pada penelitian ini membahas tentang beton geopolymer berbasis abu terbang (fly ash) hasil pembakaran batu bara pada PLTU Bukit Asam Tanjung enim Sumatera Selatan dengan aktivator potassium. Penelitian ini dilakukan untuk mengetahui pengaruh aktivator pottasium dan kondisi material, terhadap kuat tekan rencana 30 Mpa pada beton geopolymer melalui pengujian di laboratorium Fakultas Teknik Sipil Universitas Bina Darma Palembang dengan membuat 18 benda uji silinder diameter 100 mm x 200 mm, dengan fly ash dan aktivator Pottasium. Pembuatan benda uji dilakukan kondisi material aggregat dalam kondisi Saturated Surface Dry (SSD) dan kering oven pada suhu 60°C dengan waktu 1 jam, dengan perawatan benda silinder dengan suhu ruangan sampai waktu benda uji akan di uji. Produk penelitian yang dilakukan adalah grafik hubungan perilaku material kondisi SSD dan kering oven pada material beton gopolymer dalam menerima beban tekan dengan aktivator Pottasium. Dari grafik tersebut dapat dilihat bahwa, dengan kondisi material kering oven dari fly ash dan aktivator pottasium, lebih kuat dalam menerima beban tekan dengan nilai kuat tekan fc 30 Mpa.

Experimental validation of a test gas substitution for simulating non-equilibrium giant planet entry conditions in impulse facilities

Scaled giant planet entry testing is beyond the simulation capability of most impulse facilities, which limits the ground testing data available for computational model validation. Substituting the He in their predominately H/He atmospheres with Ne has been used in the previous experiments. This enables higher-temperature shock layers to be recreated using the same facility performance. For binary hydrogen dissociation and ionization reactions, the substitution gives similarity with non-equilibrium processes, but has never been experimentally validated by direct comparison with H/He relaxation data in a region where the facility simulation capabilities in using H/He and H/Ne overlap. This work demonstrates and validates a scaling method based on the substitution in terms of flow relaxation. A H/Ne condition was designed to recreate the post-shock relaxation of a H/He condition in our X2 expansion tube. The two conditions were experimentally tested with cylindrical test models, and shock layer radiation from the Balmer series was measured. The spectroscopic data using the H/Ne condition show a successful recreation of the non-equilibrium processes of the target H/He condition, experimentally validating the scaling method. High-speed images demonstrate that the associated radiation field is also correctly reproduced. With the use of this substitution, the facility can now be used to simulate high-speed giant planet entries with confidence, and the available ground testing envelope is extended to much higher speeds.

Comparative Study on Reciprocal Tribology Performance of Mono-Hybrid Ceramic Reinforced Al-9Si-3Cu Graded Composites

This research compares the reciprocating tribo-mechanical behaviour of functionally graded A333 (Al-9Si-3Cu) alloy, Al-9Si-3Cu/6wt%B4C mono-composite and Al-9Si-3Cu/6wt%B4C/4wt%TiB2 hybrid-composite. Cylindrical test samples of both alloy and composites were horizontal centrifuge cast. Metallography of alloy revealed grain refinement and throughout presence of B4C particles along the cross-section of both functionally graded composites. Whereas, a rising gradient of TiB2 particles were observed towards the outer zone of hybrid composite. Comparative analysis on micro-hardness and tensile strength, revealed an improvement of 37.4% and 17.6% respectively for outer hybrid-composite; 22.6%, and 12.2% respectively for outer mono-composite with respect to alloy. Reciprocating wear analysis confirmed superior anti-wearing at outer hybrid-composite. Worn morphological analysis confirmed predominant delamination wear mechanism for outer zones of alloy, mono and hybrid composites. Abrasive, adhesive and delamination wear in combination, led to oxide layer formation at intermediate sliding distances. Hybrid composite is functionally graded and developed for automotive engine component applications.

Examination of welded joint of titanium alloy used in oral surgery

The additive manufacturing of customized Ti-6Al-4V (Grade 23) implants, which in the present research concerns the dental and maxillofacial surgical field, may require complex manufacturing technology due to their complexity and assembly. In practice, additively manufactured titanium implant elements are supplemented by threaded sleeves that allow disassembly. These turned elements made from Grade 5 material quality rolled preform are joined by laser micro-welding with Grade 1 material. This special process for implant production is still not widespread in current manufacturing practice, and there is no technical recommendation for the manufacturing parameters of these implants. The aim of our research is to explore the possibilities and limitations of additive process in the manufacture of custom-made implants and to provide guidelines for optimal manufacturing and welding parameters. In the initial phase of the research, preliminary experiments were conducted with the conventional and additive manufacturing of cylindrical test specimens and with the production of combined products by micro-welding. The specimens were subjected to tensile testing, the weld was examined by CT, and the fracture surfaces were studied by optical microscope and scanning electron microscope.

STUDI PENAMBAHAN SUPEPRPLASTCIZER PADA KUAT TEAN BETON DENGAN VARIASI FAS 0,4 – 0,5 MENGGUNAKAN AGREGAT KASAR YANG DI PECAH (SPLIT)

This study aims to determine the effect of superplasticizer usage on concrete compressivestrenght with variation of water cement ratio using subdivided crude aggregates (split).This research cylindrical test object with diameter 15 cm and height 30 cm. Compressivestrength concrete design fc’ 35 MPa, with variation of water cement ratio W/C 0,4; 0,45; 0,5 andusing Superplasticizer Sikament LN materials 0,5% of the weight of cement and slump value 12 ± 2cm.The result of research showed an increase the value of concrete compressive strength withthe addition of superplasticizer. The average of concrete compressive strength without the addition ofsuperplasticizer and variation of water cement ratio W/C 0,4; 0,45; 0,5 at 28 days in a row is 36,14MPa, 34,73 MPa, 29,82 MPa. While the value of concrete compressive strength with the addition ofsuperplasticizer increase to 39,73 MPa, 37,18 MPa, 31,23 MPa.

Trial of new equipment for materials torsion mechanical test

The equipment for measuring mechanical and operational characteristics of materials play an important role in the process of metal products quality control. One of the methods of determining of material mechanical characteristics is the method of cylindrical samples torsion tests. The equipment available at present at Russia and Kazakhstan markets for torsion tests is manufactured mainly outside the EvrAzES countries. Therefore, elaboration and designing of domestic analogs of equipment for torsion tests is an actual task. Description and technical characteristics of the testing bench presented, developed at the Department of metals forming of the Ural Federal University after the first President of Russia B.N. El’tsin. The main features of the bench are materials mechanical torsion testing, plasticity and resistance against deformation measuring, study of hardening and softening processes. Results of new equipment trials for cylinder samples tests for unidirectional and alternating torsion presented. For the experiment 9, samples were manufactured, preliminary selected based on the computer simulation of the sample type. The samples were tested at various deformation schemes: three samples - at unidirectional torsion with torsion speed of active grip 1, 5 and 10 r/min, three pairs of samples - at alternating torsion, two amplitudes being 30 and 60 degrees and analog speed of active grip torsion. As a result of the tests, graphs of the torque were built for every sample, which showed, that amplitude at the alternative load has the biggest effect on the number of deformation cycles before a sample destruction: the smaller the amplitude is, the bigger number of cycles the sample can withstand before destruction. Based on the results of work carried out, the possibility of the bench usage for materials testing was proved.

SIMULATION AND EXPERIMENTAL INVESTIGATION OF WRINKLE DEFECT IN DEEP DRAWING PROCESS OF CARBON STEEL SPCC SHAPED CYLINDER FLANGE CUP

A Sheet Metal Forming (SMF) process, especially deep drawing, is one of the manufacturing processes that commonly used in the automotive industry. Compared with casting and forging, the SMF process has several advantages, including lesser weight materials and broader variations in shape that can be made. One of the problems in the SMF process is the wrinkling phenomenon, which can cause the size and appearance defects of sheet products. The wrinkle occurs because of the mechanical properties of the material, product geometry, and blank holder force (BHF). Several variations of BHF were applied in these simulations and experiments to eliminate the wrinkle defects of cylinder flange cup test products. The characteristic of the cylinder flange cup is from the cold-rolled coiled steel plate (SPCC) type of material with a thickness of 0.8 and 1.0 mm, the height of 10 mm, the inner diameter of 58 mm, and flange diameter of 76 mm. Simple simulations of the SMF process were carried out by using Solidworks with version 2017, and the experiment was carried out at a 600 kN press with a punch velocity of 40 strokes per minute and blank holder force variations from 0 to 21 kN. The experimental data performed with a single die on a flanged cup cylindrical test material shows that the higher the blank holder force (BHF) number, the smaller the wrinkle defect, and it can be eliminated starting from the BHF number of 15 kN.

Experimental investigation of heat transfer enhancement in pool boiling using novel Ag/ZnO hybrid nanofluids

The present study aims at investigating the enhancements in thermal properties, CHF and HTC of novel Ag/ZnO hybrid nanofluid at various concentrations. A cylindrical copper test piece of 20 mm diameter was used as a heated surface. Stable nanofluids were prepared by dispersing the hybrid nanoparticles through ultra-sonication process at three different volume concentrations (O): 0.02%, 0.06% and 0.1%. The thermal conductivity of the hybrid nanofluids was found to be 32% higher at 45 °C when compared with DI water. During pool boiling experimentation an increase in concentration led to increased heat transfer coefficient (HTC) and critical heat flux (CHF). Maximum values of CHF and HTC were found to be 65.51% and 179.92%, respectively, for O = 0.1% when compared with base fluid, i.e., DI water. Also, any further increase in volume concentration beyond 0.1% deteriorated the boiling heat transfer.

Estimation of Fracture Toughness Using Flat-Ended Cylindrical Indentation

A method is proposed to predict the fracture toughness of in-service structures using the instrumented indentation test. While previous studies have attempted to predict fracture toughness using spherical indenters, we propose the method to predict fracture toughness using flat-ended cylindrical indenters. Using the geometric similarity of a cylindrical indentation test and the Cracked Round Bar (CRB) fracture toughness test, fracture toughness values were derived from a single indentation test by assuming that the load–depth curve of the indentation test is the same as the load–displacement curve of the CRB fracture toughness test. To determine the crack initiation point, the concept of limit load in CRB testing is adopted, and a new load–depth curve is obtained using a suggestion in the standard of fracture toughness test. In order to apply the proposed method directly to in-service structures, the model uses mechanical parameters that can be obtained by indentation testing. The model was verified on metallic materials primarily used in nuclear power plants.

Underdetermined convolutive blind source separation in the time–frequency domain based on single source points and experimental validation

To effectively separate underdetermined convolutive mixtures, an accurate and robust underdetermined convolutive blind source separation (BSS) method in the time–frequency domain based on single source points (SSPs) is proposed. Firstly, convolutive BSS in the time domain is transformed into instantaneous BSS in the time–frequency domain by short-time Fourier transform (STFT). Secondly, hierarchical clustering is carried out after the extraction and identification of SSPs by using sparse coding technology. Thirdly, source separation in the frequency domain is obtained based on Lp norm minimization and then alignments are permutated and scales are compensated. Finally, inverse STFT is adopted to reconstruct the separated signals in the time domain. Furthermore, numerical case studies and experimental case studies on a cylindrical test bed are carried out to validate the effectiveness of the proposed method. Generally, this paper provides an accurate and robust underdetermined convolutive BSS technique for mixing matrix estimation, source identification and contribution evaluation, which can provide significant evidence for vibration and noise monitoring and control.

CONCRETO PRODUZIDO COM AGREGADO GRAÚDO LATERÍTICO EM SANTARÉM, PARÁ

RESUMO: Avaliou-se a substituição da brita basáltica existente no concreto por material alternativo em abundância no município de Santarém-PA: a laterita. Foi avaliado o desempenho do concreto incorporado com agregado laterítico in natura em substituição parcial ao agregado graúdo de brita basáltica nos teores de 20% e 50%. Realizou-se a caracterização dos agregados graúdo e miúdo. De acordo com o método da ABCP, determinou-se o traço de referência em massa 1:1,71:3,03:0,53; confeccionou-se corpos-de-prova cilíndricos 10x20 cm utilizando 3 traços diferentes, de modo a substituir a brita basáltica pelo agregado laterítico, em 20% e 50%. Para cada traço foram quantificados a sua consistência, por meio do ensaio de abatimento do tronco de cone, resistência à compressão axial, resistência à tração por compressão diametral e módulo de elasticidade aos 28 dias. A substituição do agregado convencional de brita basáltica por agregado laterítico em seu estado natural promoveu diminuição da resistência a compressão simples, da resistência à tração por compressão diametral e do módulo de elasticidade com a inclusão do agregado laterítico na mistura. Destaca-se que acima de determinado teor de substituição o concreto torna-se inviável devido a necessidade de adicionar aditivo plastificante para manter a consistência desejada e que as duas misturas incorporadas com agregado laterítico se mostraram muito semelhantes após os 28 dias, no que tange a ganhos de resistência a compressão.
 ABSTRACT: This study is about the replacement of basaltic origin crushed stone by alternative material present in the municipality of Santarém, Pará State: the laterite. The aim were to evaluate the performance of concrete incorporated with natural lateritic aggregate, replacing the of crushed stone in 20% and 50%. The first stage was characterizing the coarse and fine aggregates that made up the studied concrete. According to ABCP dosing method it was determined the mass reference trait 1: 1.71: 3.03: 0.53; bodies of 10x20 cm were made for cylindrical test, using three different strokes so that the basaltic crushed stone gradually replaced by the lateritic aggregate in proportions of 20% and 50%. For each trait its consistency was quantified by means of the tapering test, axial compression strength, diametric compression tensile strength and the modulus of elasticity at 28 days. Was observed that the replacement of the conventional aggregate basalt crushed stone for aggregate of laterite in natural state promoted a decrease in the value of simple compressive strength, diametric tensile strength and modulus of elasticity with inclusion of a larger amount of lateritic aggregate in the mixture. It is noteworthy that above a certain substitution content, the concrete becomes not feasible due to the need for a large increase in the amount of plasticizer additive to the desired consistency is maintained and the two blends incorporated with lateritic showed very similar after 28 days in terms of gains in compressive strength.

Electromagnetic analysis of cylindrical WCCB TBM

Abstract In this study, electromagnetic analyses of cylindrical water-cooled ceramic breeder test blanket module under the three types of ITER plasma disruption scenarios were conducted. Highest Lorentz force (LF) along radial direction was observed under plasma disruption scenario of MD-II. Symmetrical LF along two-eight o'clock position was observed in side wall (SW) of container and could be canceled in summation. Integrated LF of a container was mainly contributed by first wall and rear part of SW. Compared with previous design of box-shaped container, lower magnitude of LF was shown in current design of cylindrical container, which was mainly understood by difference in the volume of the solid structure. Maxwell force (MF) was additionally evaluated considering the ferromagnetic characteristic of F82H. Magnitude and distribution of MF was much higher than LF. Besides connection structure, the structural integrity of container should be taken into account when ferromagnetic characteristics were considered.