Статті в журналах: "Plastiska deformationer"

1

Nakajima, N., and E. R. Harrell. "Rheology of PVC Plastisol - VIII: Mechanism of Non-Linear Viscoelastic Behavior." Rubber Chemistry and Technology 76, no. 5 (November 1, 2003): 1074–90. http://dx.doi.org/10.5254/1.3547788.

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Abstract The mechanism of the strain-amplitude dependence (non-linearity) of viscoelastic properties of a PVC plastisol was examined. The range of amplitude was 0.02 to 10.24 and the range of frequency was 0.1 to 100 rad/s. The amplitude dependence of dynamic viscosity was very similar to its frequency dependence in that with the increase of amplitude or frequency it decreased first, reaching a minimum and then increased. In the preceding series of papers, the decrease of viscosity with the increase of frequency, i.e. pseudo-plasticity, was attributed to shear-induced phase separation into immobilized layer and mobile phase. In the present work, it is shown that the same mechanism is responsible for the decrease of viscosity with the increase of amplitude. The increase of viscosity with the increase of amplitude (after the minimum) is explained by the dilatation of the immobilized layer. Subsequently, the normal stress acting on the immobilized layer is calculated from the difference of the osmotic pressure between the mobile phase and immobilized layer. The shear deformation of the immobilized layer is estimated to be extremely small, although the deformation in the normal direction, i.e. the dilatation, is significant.

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2

Yaqin, Rizqi Ilmal, Mega Lazuardi Umar, Sigiet Haryo Pranoto, Angger Bagus Prasetiyo, and Bambang Hari Priyambodo. "STUDI PERANCANGAN PISAU PADA MESIN PENCACAH PLASTIK MENGGUNAKAN FINITE ELEMENT ANALYSIS." JTT (Jurnal Teknologi Terapan) 7, no. 1 (May 19, 2021): 44. http://dx.doi.org/10.31884/jtt.v7i1.320.

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The amount of plastic waste each year will increase by 10% every year which is a problem for a country. Therefore, proper processing of plastic waste needs to be done. Before being processed into plastic waste processing, it is necessary to have a chopping process using a plastic chopping machine. The plastic chopping machine has an important component, namely the chopping knife. Before carrying out the knife manufacturing process, it is necessary to validate the design of the blade that is used with its loading. Model simulation using software is one way to quickly validate the model. This study aims to determine the effect of loading variations on stress, strain, deformation and safety factors of the model. The use of ANSYS R17.2 software is used to analyze the chopping machine knife model with a variation of 5kg / hour, 10kg / hour, 20kg / hour and 50kg / hour capacities. The result is that the stress, strain and deformation parameters have an increase in value with increasing loading variations. The greatest values of stress, strain and deformation are in the variation of 50kg / hour respectively 64.995 Pa; 336.76 and 56,358 x 10-11mm. The value of the safety factor for all variations of loading has a value of 15. The value of the safety factor means that the design of the plastic chopping knife is safe to use up to a loading of 50kg / hour

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3

Setiyana, Budi, Imam Syafaat, Jamari Jamari, and DikJoe Schipper. "FRICTION ANALYSIS ON SCRATCH DEFORMATION MODES OF VISCO-ELASTIC-PLASTIC MATERIALS." Reaktor 14, no. 3 (February 3, 2013): 199. http://dx.doi.org/10.14710/reaktor.14.3.199-203.

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Understanding of abrasion resistance and associated surfaces deformation mechanisms is of primary importance in materials engineering and design. Instrumented scratch testing has proven to be a useful tool for characterizing the abrasion resistance of materials. Using a conical indenter in a scratch test may result in different deformation modes, like as elastic deformation, ironing, ductile ploughing and cutting. This paper presents the friction analysis of some deformation modes of visco-elastic-plastic behaving polymer materials, especially PEEK (poly ether ether ketone).In general, it is accepted that the friction consist of an adhesion and a deformation component, which can be assumed to be independent to each others. During a scratch test, the friction coefficient is influenced by some parameters, such as the sharpness of indenter, the deformation modes and the degree of elastic recovery. Results show that the adhesion component strongly influences the friction in the elastic and ironing deformation mode (scratching with a blunt cone), friction for the cutting deformation mode (scratching with a sharp cone) is dominantly influenced by the deformation component. From the analysis, it can be concluded that the adhesion friction model is suitable for ironing - elastic deformation mode and the deformation friction model with elastic recovery is good for cutting mode. Moreover, the ductile ploughing mode is combination of the adhesion and plastic deformation friction model. ANALISIS FRIKSI PADA BENTUK DEFORMASI AKIBAT GORESAN PADA MATERIAL VISKO-ELASTIK-PLASTIK. Pemahaman tentang ketahanan abrasi dan deformasi permukaan yang menyertainya merupakan hal yang penting dalam rekayasa dan disain material. Peralatan uji gores terbukti ampuh untuk menyatakan ketahanan abrasi dari material. Pemakaian indenter kerucut dalam uji gores akan menghasilkan beberapa bentuk deformasi seperti halnya deformasi elastik, penyetrikaan, plowing dan pemotongan. Paper ini menyajikan analisis friksi dari beberapa bentuk deformasi permukaan dari material visko-elastik-plastik, khususnya pada PEEK (poly ether ether ketone). Secara umum dinyatakan bahwa friksi terdiri dari komponen adhesi dan deformasi yang diasumsikan tidak bergantung satu sama lain. Selama uji gores, koefisien friksi dipengaruhi oleh beberapa parameter, seperti ketajaman indenter, bentuk deformasi dan pemulihan elastik. Hasil menunjukkan bahwa komponen adhesi sangat berpengaruh pada deformasi elastic dan penyetrikaan (uji gores dengan indenter tumpul), sedang untuk pemotongan (uji gores dengan indenter tajam) sangat dipengaruhi oleh komponen deformasi. Dari analisis dapat disimpulkan bahwa model friksi adhesi cocok untuk deformasi elastic dan penyetrikaan, sedang model friksi deformasi dengan pemulihan elastic, cocok untuk pemotongan. Selain itu, plowing merupakan kombinasi dari model friksi adhesi dan deformasi.

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4

Santana, Elvis. "Congenital luxation of the knee: with regard to a case." Clinical Orthopaedics and Trauma Care 2, no. 2 (October 21, 2020): 01–04. http://dx.doi.org/10.31579/2694-0248/007.

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The congenital luxation of the knee is an unfrequent affection, existing many theories about it's appearance. In some cases, it is considered an isolated deformation although it is relativly frequent to associate it to other congenital malformations, such as the dysplasia on the development of the hip, feet deformities or dislocation of the elbow. The treatment of this kind of affection depends on the seriousness and flexibility of the fondness, having like therapeutic lines the placing of serial casts, by using Pavlik's armor or plastia of the four headed muscle on severe cases. We present a case of congenital luxation of the knee treated by the use of serial casts, with a favorable evolution.

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5

Erkamp, R. Q., P. Wiggins, A. R. Skovoroda, S. Y. Emelianov, and M. O'Donnell. "Measuring the Elastic Modulus of Small Tissue Samples." Ultrasonic Imaging 20, no. 1 (January 1998): 17–28. http://dx.doi.org/10.1177/016173469802000102.

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Independent measurements of the elastic modulus (Young's modulus) of tissue are a necessary step in turning elasticity imaging into a clinical tool. A system capable of measuring the elastic modulus of small tissue samples was developed. The system tolerates the constraints of biological tissue, such as limited sample size (≤1.5 cm3) and imperfections in sample geometry. A known deformation is applied to the tissue sample while simultaneously measuring the resulting force. These measurements are then converted to an elastic modulus, where the conversion uses prior calibration of the system with plastisol samples of known Young's modulus. Accurate measurements have been obtained from 10 to 80 kPa, covering a wide range of tissue modulus values. In addition, the performance of the system was further investigated using finite element analysis. Finally, preliminary elasticity measurements on canine kidney samples are presented and discussed.

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6

Skaržauskas, Valentinas, Dovilė Merkevičiūtė, and Juozas Atkočiūnas. "LOAD OPTIMIZATION OF ELASTIC-PLASTIC FRAMES AT SHAKEDOWN/PRISITAIKANČIŲ TAMPRIAI PLASTIŠKŲ RĖMŲ APKROVOS OPTIMIZACIJA." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 7, no. 6 (December 31, 2001): 433–40. http://dx.doi.org/10.3846/13921525.2001.10531769.

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In this article the theory of mathematical programming is used, composing improved mathematical models of nonlinear problems of frame loading optimization at shakedown and performing its numerical experiment. An elastic perfectly-plastic frame is considered. Frame geometry, material, load application places are considered known. Time independent load variation bounds are variable (history of loading is unknown). Mathematical model of load variation bounds optimization problem includes strength and stiffness constrains. The mentioned optimization load combines two problems. First problem is connected with the distribution of statically admissible moments at shakedown. This is a problem of residual bending moments analysis which is presented in two ways. In the first case it is formulated as a quadratic programming problem, where the objective function is non-linear, but the objective function of load optimization problem remains linear. The problem is solved by iterations, influential matrixes of residual displacements, and stresses are used. In next case, the equations of problem analysis and dependences are presented according to complete equation system of plasticity theory. Then the objective function of optimization problem becomes non-linear and it is solved in single stage. Solving the second problem, we check if it is possible to satisfy frame rigidity constrains, which are inferior or superior limits of residual displacement. This is considered as a linear programming problem. Mathematical model of frame load optimization problem at shakedown was made with the help of non-linear mathematical programming theory. Numerical experiment was realized with Rozen's gradients projecting method and using the penalty function techniques. Mathematical programming complementarity conditions prohibit taking into account the dechargable phenomena in some cross-sections, therefore analysis of residual deformation compatibility equations are performed, using linear mathematical programming.

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7

Febriyanti, Eka, Dedi Priadi, and Rini Riastuti. "Pengaruh Peningkatan Derajat Deformasi Canai Hangat Terhadap Karakteristik Deformation Band Paduan Cu-Zn 70/30." Material Komponen dan Konstruksi 15, no. 2 (February 22, 2019): 9. http://dx.doi.org/10.29122/mkk.v15i2.3373.

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Abstract Cu-Zn 70/30 alloy has properties that is relatively soft, ductile, and easy to perform by cold working. However, cold working has the disadvantage that require equipment which has higher loading capacity to generate strength and higher density thus increasing of machining cost. In addition, strain hardening phenomenon due to cold working process resulted in decreasing of ductility material. Therefore, it is necessary alternative fabrication processes to optimize the mechanical properties of Cu-Zn alloy 70/30 that with the TMCP method. TMCP is metal forming material by providing large and controlled plastic strain to the material. TMCP using the deformation percentage variation that 32.25%, 35.48%, and 38.7% from hot rolled research at 500°C temperature in double pass reversible which performed on Cu-Zn 70/30 plate. By tensile testing using universal testing machine can be seen that the Cu-Zn 70/30 alloy on 32.25% degree of deformation, both of UTS and YS respectively are 505 MPa and 460 MPa. Whereas from examination of thickness and density deformation bands by FE-SEM shows denser and thicker deformation band proportional with increasing of deformation degree.Moreover, the values of tensile strength at the edge of the area and the center is directly proportional to the density and thickness of the deformation band. Paduan Cu-Zn 70/30 memiliki sifat yang relatif lunak, ulet, dan mudah dilakukan pengerjaan dingin. Namun, pengerjaan dingin memiliki kekurangan yaitu membutuhkan peralatan yang memiliki kapasitas pembebanan tinggi untuk menghasilkan kekuatan dan kepadatan tinggi sehingga meningkatkan biaya permesinan. Selain itu, fenomena pengerasan regang akibat proses pengerjaan dingin menghasilkan penurunan keuletan material. Oleh karena itu, diperlukan alternatif proses fabrikasi untuk mengoptimalkan sifat mekanik paduan Cu-Zn 70/30 salah satunya dengan metode TMCP. TMCP merupakan suatu proses perubahan bentuk suatu material dengan cara memberikan regangan plastis yang besar dan terkontrol terhadap material. TMCP dengan menggunakan variasi persentase deformasi sebanyak 32,25%, 35,48%, dan 38,70% dari penelitian canai hangat di suhu 500oC secara double pass reversible dilakukan pada pelat paduan Cu-Zn 70/30. Dengan melakukan pengujian tarik menggunakan mesin uji tarik universal testing machine dapat dilihat bahwa pada material paduan Cu-Zn 70/30 pada derajat deformasi 32,25% menghasilkan nilai UTS dan YS masing-masing sebesar 505 MPa dan 460 MPa. Sedangkan dari hasil pengamatan ketebalan dan kerapatan deformation band menggunakan FE-SEM menunjukkan deformation band yang lebih rapat dan lebih tebal sebanding dengan semakin meningkatnya derajat deformasi. Selain itu, nilai kekuatan tarik pada daerah tepi dan tengah berbanding lurus dengan kerapatan dan ketebalan deformation band. Keywords: 70/30 Cu-Zn alloy, warm rolled, deformation degree, deformation bands

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8

Nakajima, Nobuyuki. "Time-dependent thermodynamics applied to flow of suspensions and polymer melts." Journal of Elastomers & Plastics 48, no. 8 (July 28, 2016): 754–60. http://dx.doi.org/10.1177/0095244315618701.

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Rheological behavior has been treated in terms of the energy flow by coupling it with deformation and flow of material. The method follows time-dependent thermodynamics, which is different from Prigogine’s irreversible thermodynamics. We have examined the rate of energy production with particular attention to the physical meaning of the sign of the rate. Just as the sign of energy indicates in thermodynamics, whether or not the reaction is spontaneous, the sign of the rate indicates in time-dependent thermodynamics, whether or not the reaction is stable. In the stable region, the reaction is reversible. For a change from stable region to an unstable region, there is a discontinuity. Then, there is a pseudo-stable region, where a partial reversibility may be observed. This behavior involves yielding, which leads to fracture, like that seen in a longtime creep failure of a solid material. We have examined non-Newtonian flow of polyvinyl chloride plastisol, steady-state flow of high-density polyethylene melts, and its stress growth toward steady state.

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9

Baikovs, Andris, and Kārlis Rocēns. "PREDICTION OF THE ANTICLASTIC SHAPE CHANGES OF HYBRID COMPOSITE MATERIAL." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 16, no. 2 (June 30, 2010): 222–29. http://dx.doi.org/10.3846/jcem.2010.25.

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In search of structurally better and aesthetically more attractive solutions of the erection of various structures, non‐standard anticlastic elements are used more frequently. Therefore preservation of the initial shape of timber composite material sheets by using of reinforced plastic reinforcement has been investigated. Calculation model for determination of the thickness of rational reinforcement anticlastic sheet, which provides change of the original bending radius under variable moisture conditions (Baikovs and Rocens, 2006) within the limits of preferable intervals is developed by authors and using finite element method, calculations and modelling of sheet deformations are carried out with software package ANSYS v.11 (henceforth FEM) and by developed analytical method. Comparative research of the results calculated with the FEM and developed calculation model showed that the difference between results in the three cases investigated, when the composite timber material is reinforced on the top, bottom and both sides for the most of the cases does not exceed 3.3%. An opportunity to provide the original shape of anticlastic timber composite material sheets by using glass fibre reinforced plastic reinforcement under variable moisture conditions and not exceeding the difference of 5% has been demonstrated. Santrauka Ieškant ivairiu konstrukciju statiniu konstrukciškai geresniu ir estetiškai patrauklesniu sprendiniu, dažniausiai naudojami nestandartiniai antiklastiniai elementai. Todel buvo tyrinetas medienos kompozitines medžiagos lakštu pradinio pavidalo išsaugojimas naudojant sustiprinta plastiko armatūra. Skaičiuojamasis modelis, padedantis nustatyti racionaliai armuoto antiklastinio lakšto stori, kuris pakeičia pradini lenkimo spinduli kintamomis dregmes salygomis (Baikovs, Rocens 2006) tarp priimtinu intervalu ribu, yra sukurtas autoriu ir, taikant baigtiniu elementu metoda, lakšto deformaciju skaičiavimai bei modeliavimas atlikti kompiuteriniu programu paketu ANSYS v. 11 (toliau ‐ FEM) ir pagal sukurta analitini metoda. Rezultatu, apskaičiuotu su FEM ir pagal sukurta analitini modeli, lyginamasis tyrimas parode, kad skirtumas tarp triju tirtu atveju, kai medienos kompozitine medžiaga yra armuota viršuje, apačioje ir iš abieju pusiu, rezultatai daugeliu atveju neviršija 3,3%. Parodyta galimybe suteikti originalu pavidala antiklastiniams medienos kompozitiniams lakštams naudojant stiklo pluoštu sustiprinto plastiko armatūra ivairiomis dregmes salygomis ir neviršijant 5% skirtumo.

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10

Fiorito, Marco, Daniel Fovargue, Adela Capilnasiu, Myrianthi Hadjicharalambous, David Nordsletten, Ralph Sinkus, and Jack Lee. "Impact of axisymmetric deformation on MR elastography of a nonlinear tissue-mimicking material and implications in peri-tumour stiffness quantification." PLOS ONE 16, no. 7 (July 9, 2021): e0253804. http://dx.doi.org/10.1371/journal.pone.0253804.

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Solid tumour growth is often associated with the accumulation of mechanical stresses acting on the surrounding host tissue. Due to tissue nonlinearity, the shear modulus of the peri-tumoural region inherits a signature from the tumour expansion which depends on multiple factors, including the soft tissue constitutive behaviour and its stress/strain state. Shear waves used in MR-elastography (MRE) sense the apparent change in shear modulus along their propagation direction, thereby probing the anisotropic stiffness field around the tumour. We developed an analytical framework for a heterogeneous shear modulus distribution using a thick-shelled sphere approximation of the tumour and soft tissue ensemble. A hyperelastic material (plastisol) was identified to validate the proposed theory in a phantom setting. A balloon-catheter connected to a pressure sensor was used to replicate the stress generated from tumour pressure and growth while MRE data were acquired. The shear modulus anisotropy retrieved from the reconstructed elastography data confirmed the analytically predicted patterns at various levels of inflation. An alternative measure, combining the generated deformation and the local wave direction and independent of the reconstruction strategy, was also proposed to correlate the analytical findings with the stretch probed by the waves. Overall, this work demonstrates that MRE in combination with non-linear mechanics, is able to identify the apparent shear modulus variation arising from the strain generated by a growth within tissue, such as an idealised model of tumour. Investigation in real tissue represents the next step to further investigate the implications of endogenous forces in tissue characterisation through MRE.

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11

Jusuf, Annisa, Afdhal Afdhal, and Minda Mora. "Kajian Desain Kelaiktabrakan Pesawat Terbang." WARTA ARDHIA 42, no. 3 (September 22, 2017): 117. http://dx.doi.org/10.25104/wa.v42i3.241.117-122.

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Lalu lintas penerbangan di Indonesia mengalami tren peningkatan dari tahun ke tahun. Peningkatan frekuensi penggunaan pesawat terbang tentunya akan meningkatkan kemungkinan kejadian kecelakaan. Konsep kelaiktabrakan pesawat terbang menjadi hal penting yang perlu mendapat perhatian untuk mencegah kerusakan struktur dan cedera pada penumpang. Desain kelaiktabrakan struktur pesawat berada pada tahapan desain awal yang terintegrasi kedalam proses desain pesawat secara keseluruhan. Struktur subfloor pada pesawat terbang menjadi bagian yang digunakan untuk menyerap energi kinetik tabrakan dalam kasus pembebanan vertikal pada pesawat terbang. Crash box merupakan komponen pada subfloor yang akan menyerap energi kinetik tabrakan dengan mengubahnya menjadi deformasi plastis. [A Review of Aircraft Crashworthiness Design] Air traffic in Indonesia is experiencing a positive trend in recent years. The increase in the frequency of aircraft operation might particularly increase the possibility of accidents occurrence. Aircraft crashworthiness concept becomes an important matter that need to be considered in order to prevent structural damage and injuries to the passengers. Aircraft structural crashworthiness design is developed in the aircraft preliminary design phase which is, later, integrated into the overall aircraft design process. Aircraft subfloor structure is the part of the aircraft that is used to restrain the kinetic energy of a collision in the case of vertical loading on the aircraft. Subsequently, crash box is a component of the subfloor that will absorb collisions kinetic energy by turning it into plastic deformation.

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12

Maulana, Rahmad, Muhammad Razi, and Saifuddin A Jalil. "ANALISA TEGANGAN PADA PLUG VALVE MENGGUNAKAN METODE ELEMEN HINGGA BERBASIS SIMULASI." Jurnal Mesin Sains Terapan 4, no. 2 (November 4, 2020): 91. http://dx.doi.org/10.30811/jmst.v4i2.2013.

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Plug Valve adalah katup gerakan rotasi seperempat putaran yang menggunakan plug meruncing atau silinder untuk menghentikan atau mengarahkan laju aliran fluida. Plug Valve bisa dipakai mulai dari tekanan atmosfir hingga 10.000 psi (69.000 KPa) dan suhu dari 50 hingga 1.500 0F. Dalam penelitian ini, dilakukan analisa tegangan yang terjadi pada body plug valve akibat tekanan laju aliran fluida menggunakan Metode Elemen Hingga Ansys Workbench. Pada penelitian ini, body plug valve diberikan variasi tekanan Working Pressure berdasarkan standard ASME B16.34 pada suhu material 300ºC yang kemudian dengan Test Pressure hingga tegangan yang terjadi mencapai batas Yield Tensile Strength material ASTM A216 Grade WCB yaitu sebesar 280 MPa. Hasil tegangan yang didapat berdasarkan hasil simulasi pada body plug valve yang dimodelkan didalam software Ansys Workbench didapatkan bahwa pada Working Pressure 1.02 MPa tegangan maksimum yang terjadi sebesar 3.7625 MPa, selanjutnya pada Test Pressure 16 MPa didapatkan tegangan maksimum sebesar 59.02 MPa, lalu pada Test Pressure 36 MPa didapatkan tegangan maksimum sebesar 132.8 MPa, kemudian pada Test Pressure 56 MPa didapatkan tegangan maksimum sebesar 206.57 MPa, dan pada Test Pressure 76 MPa didapatkan nilai tegangan maksimum sebesar 280.35 MPa. Berdasarkan variasi tekanan yang diberikan pada body valve didapatkan, pada test pressure 76 MPa tegangan maksimum yang terjadi sudah melewati nilai batas Yield Tensile Strength dari material yang dipakai, dalam kondisi ini body plug valve akan mengalami kegagalan distrosi deformasi plastis (plastic deformation), dimana semua perubahan yang terjadi akan terjadi secara permanen dan akan terus berlanjut hingga mencapai batas tegangan maksimum material. Kata kunci: Body, Plug Valve, Tegangan Maksimum, Pressure

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13

Febriyanti, Eka, Dedi Priadi, and Rini Riastuti. "PENGARUH PENINGKATAN DERAJAT DEFORMASI CANAI HANGAT TERHADAP KARAKTERISTIK DEFORMATION BAND PADUAN Cu-Zn 70/30." Material Komponen dan Konstruksi 16, no. 1 (June 1, 2016). http://dx.doi.org/10.29122/mkk.v16i1.3286.

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Cu-Zn 70/30 alloy has properties that is relatively soft, ductile, and easy to perform by cold working. However, cold working has the disadvantage that require equipment which has higher loading capacity to generate strength and higher density thus increasing of machining cost. In addition, strain hardening phenomenon due to cold working process resulted in decreasing of ductility material. Therefore, it is necessary alternative fabrication processes to optimize the mechanical properties of Cu-Zn alloy 70/30 that with the TMCP method. TMCP is metal forming material by providing large and controlled plastic strain to the material. TMCP using the deformation percentage variation that 32.25%, 35.48%, and 38.7% from hot rolled research at 500°C temperature in double pass reversible which performed on Cu-Zn 70/30 plate. By tensile testing using universal testing machine can be seen that the Cu-Zn 70/30 alloy on 32.25% degree of deformation, both of UTS and YS respectively are 505 MPa and 460 MPa. Whereas from examination of thickness and density deformation bands by FE-SEM shows denser and thicker deformation band proportional with increasing of deformation degree.Moreover, the values of tensile strength at the edge of the area and the center is directly proportional to the density and thickness of the deformation band.AbstrakPaduan Cu-Zn 70/30 memiliki sifat yang relatif lunak, ulet, dan mudah dilakukan pengerjaan dingin. Namun, pengerjaan dingin memiliki kekurangan yaitu membutuhkan peralatan yang memiliki kapasitas pembebanan tinggi untuk menghasilkan kekuatan dan kepadatan tinggi sehingga meningkatkan biaya permesinan. Selain itu, fenomena pengerasan regang akibat proses pengerjaan dingin menghasilkan penurunan keuletan material. Oleh karena itu, diperlukan alternatif proses fabrikasi untuk mengoptimalkan sifat mekanik paduan Cu-Zn 70/30 salah satunya dengan metode TMCP. TMCP merupakan suatu proses perubahan bentuk suatu material dengan cara memberikan regangan plastis yang besar dan terkontrol terhadap material. TMCP dengan menggunakan variasi persentase deformasi sebanyak 32,25%, 35,48%, dan 38,70% dari penelitian canai hangat di suhu 500oC secara double pass reversible dilakukan pada pelat paduan Cu-Zn 70/30. Dengan melakukan pengujian tarik menggunakan mesin uji tarik universal testing machine dapat dilihat bahwa pada material paduan Cu-Zn 70/30 pada derajat deformasi 32,25% menghasilkan nilai UTS dan YS masing-masing sebesar 505 MPa dan 460 MPa. Sedangkan dari hasil pengamatan ketebalan dan kerapatan deformation band menggunakan FE-SEM menunjukkan deformation band yang lebih rapat dan lebih tebal sebanding dengan semakin meningkatnya derajat deformasi. Selain itu, nilai kekuatan tarik pada daerah tepi dan tengah berbanding lurus dengan kerapatan dan ketebalan deformation band.Keywords: 70/30 Cu-Zn alloy, warm rolled, deformation degree, deformation bands

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14

Febriyanti, Eka. "Fenomena Fatik Pada Baut Penyebab Kerusakan Piston Mesin Diesel Suatu Unit Alat Berat Buldozer." Jurnal Sains dan Teknologi Indonesia 16, no. 2 (March 8, 2019). http://dx.doi.org/10.29122/jsti.v16i2.3410.

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Bolt is important component of diesel engine in bulldozer heavy equipment which has function to tight a piston component, so bolt generally experiences tensile load and torque load in its operation. In this research, showed that the bolt failed during diesel engine operation. Therefore, it is necessary to do a detailed analysis of the main causes bolt failure. Observation and examination include visual observation, fracture surface observation by Scanning Electron Microscope (SEM), metallographic examination, hardness test, tensile testing, and chemical composition analysis by optical emission spectroscopy. Detail analysis of the failed bolt was caused by fatigue failure. The failure of bolt was initiated by plastic deformation such as indentation on the outer bolt surface. Incompatibility of clamping and tightening mechanism is allegedly the caused of the indentation on the bolt. The indentation on outer bolt surface acts as stress riser. With the presence of material defect such as MnS inclusion from metallographic examination, vibration, tensile and torque residual stress during operation, fatigue crack formed and propagated until material is no longer able to withstand load that resulted final fracture.Baut merupakan komponen penting suatu mesin diesel pada sebuah unit alat berat buldozer yang salah satunya berfungsi untuk mengencangkan komponen piston. Oleh karena itu, menyebabkan baut tersebut sering mengalami pembebanan tarik dan torsi dalam pengoperasiannya. Pada penelitian ini menunjukkan bahwa baut rusak selama mesin diesel beroperasi. Untuk mengetahui detail penyebab utama kerusakan yang terjadi pada baut perlu dilakukan analisis yang mendalam. Tahapan yang dilakukan antara lain pemeriksaan visual, pengamatan fraktografi dari permukaan patahan baut dengan menggunakan SEM, pengamatan metalografi, pengujian kekerasan, pengujian tarik, dan analisis komposisi kimia material baut. Dari hasil pengamatan dan pengujian menunjukkan bahwa kerusakan baut disebabkan karena pembebanan fatik dimana kerusakan awal ditandai dengan adanya deformasi plastis berupa indentasi/penjejakan di permukaan luar baut. Oleh karena itu, ketidaksesuaian dalam mekanisme pengencangan dan penjepitan piston menyebabkan terjadinya indentasi/penjejakan. Indentasi/penjejakan di permukaan luar baut berperan sebagai peningkat tegangan. Dengan adanya kehadiran cacat material seperti inklusi MnS seperti yang terlihat dari hasil pengamatan metalografi, ditambah dengan getaran, tegangan tarik, dan torsi selama pengoperasian maka retak fatik terbentuk dari indentasi/penjejakan dan merambat sampai material baut tidak dapat menahan beban dan akhirnya patah.Keywords: bolt, inclusion, indentation, vibration, fatigue

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Setiawan, Yusup, Sri Purwati, Krisna Aditya Wardhana, Aep Surahman, and Reza Bastari Wattimena. "POTENCY OF SOLID WASTE OF PAPER MILL USING RECYCLE PAPER AS FUEL." JURNAL SELULOSA 2, no. 02 (May 12, 2016). http://dx.doi.org/10.25269/jsel.v2i02.36.

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The paper industry generates solid waste such as wastewater sludge and paper mill rejects. The rejects from recycled paper processing are varies from 5 % to 25 % dependent on the recovered fiber quality and process used in the mill. The composition of the rejects is consisted of fiber bundles, plastics pieces, foils and polystyrene containing large quantities of plastics. One of the limitations of solid waste for energy is bulky and high moisture content which is difficult to be stored, transported, and utilized. To overcome this limitation, it is needed a solidification process. Pelletizing of paper mill solid waste is one of solidification processes to ease in storing, handling, and transporting of solid waste. Experiment on solid wastes utilization in the pellet form as fuel has been carried out. Solidification process of paper mill solid waste is consisted of drying, shredding and pelletizing processes of solid waste. Pellet of paper mill solid waste and coal and pellet of combination of rejects waste were analyzed for their proximate, mineral content of ash and ash fusion temperature (AFT) to see slagging and fouling potency. The results shows that paper mill reject contain high calorific value of 5,987 calorie/gram and low content of sulphur and ash. Ash has low content of total alkali (Na2O and K2O) and high initial deformation temperature (IDT) of 1,193oC. Mixed of 95% coal and 5% pellet of reject waste has low content of total alkali (Na2O and K2O) and high initial deformation temperature (IDT) of 1,315oC. The result indicates low slagging and fouling potency of reject waste when it is utilized as a boiler fuel.Keywords: solid waste, sludge, rejects, pellet, fuel, slagging, fouling ABSTRAK Industri kertas menghasilkan limbah padat seperti limbah lumpur dan limbah reject. Jumlah limbah reject dari pengolahan kertas daur ulang bervariasi dari 5% sampai 25% tergantung pada kualitas serat dan proses yang digunakan di pabrik. Komposisi limbah reject terdiri dari gumpalan serat, potongan plastik dan foil. Salah satu keterbatasan dari limbah padat untuk energi adalah ruah dan kadar air-nya tinggi yang menyulitkan dalam penyimpanan, transportasi, dan penggunaannya. Untuk mengatasi keterbatasan ini diperlukan proses solidifikasi. Pembuatan pellet dari limbah padat industri kertas merupakan salah satu proses solidifikasi untuk memudahkan dalam penyimpanan, penanganan, dan pengangkutan limbah padat. Penelitian pemanfaatan limbah padat dalam bentuk pelet sebagai bahan bakar untuk energi telah dilakukan. Proses solidifikasi limbah padat pabrik kertas terdiri dari proses pengeringan, proses pencacahan dan proses pembuatan pellet. Pellet limbah padat industri kertas dan campuran dari batubara dan pellet limbah reject diuji untuk analisis proksimat, kadar mineral abu, kadar abu dan suhu fusi abu (AFT) untuk mengetahui potensi slagging dan fouling. Hasil menunjukkan bahwa limbah reject industri kertas mengandung nilai kalor tinggi 5.987 kalori/gram dan rendah sulfur dan abu. Abu mengandung alkali total (Na2O dan K2O) rendah dan suhu deformasi awal tinggi (IDT) yaitu 1.193oC. Campuran dari batubara 95% dan pellet limbah reject 5% mengandung alkali total (Na2O dan K2O) rendah dan suhu deformasi awal tinggi (IDT) yaitu 1.315oC. Hal ini menunjukkan potensi slagging dan fouling rendah bilamana limbah reject digunakan sebagai bahan bakar boiler.Kata kunci: limbah padat, lumpur, reject, pelet, bahan bakar, slagging, fouling

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Статті в журналах з теми "Plastiska deformationer"

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