Crack growth analysis in friction stir welded joint zones using extended finite element method

U ovom radu je prikazana analiza rasta prsine u zonama zavarenog spoja izvedenog postupkom frikcionog zavarivanja mešanjem (FSW). Ploče od legure aluminijuma 2024-T351 su sučeono zavarene primenom postupka FSW. Ploče su modelirane primenom softvera ABAQUS. Osobine materijala u zonama zavarenog spoja su prihvaćene iz radova drugih autora. Ploča je podvrgnuta zamornom opterećenju zatezanjem sa faktorom nesimetričnosti ciklusa R = 0. Rast prsline je praćen (za nestacionarnu prslinu) i faktori intenziteta napona su analizirani u okolini vrha prsline za svaki front prsline. Proširena metoda konačnih elemenata (XFEM) u ovoj analizi je omogućila automatsku generaciju mreže oko vrha prsline kod svakog koraka tokom njenog rasta. Cilj ovog rada je procena integriteta konstrukcije sa inicijalnom prslinom, dobijene frikcionim zavarivanjem mešanjem.Presented in this paper is the analysis of crack growth in zones of a welded joint, obtained by Friction Stir Welding - FSW. Plates of aluminium alloy 2024-T351 are frontally welded using the FSW procedure. Plate models are made using ABAQUS software. Material properties in the weld zones are adopted from papers by other authors. The plate is subjected to tensile fatigue loading with cycle asymmetry factor of R = 0. The crack growth is observed (for a non-stationary crack) and stress intensity factors are analysed around the crack tip for every crack front. The eXtended Finite Element Method (XFEM) in this analysis has enabled automatic mesh generation around the crack tip for every step of its growth. The aim of this paper is the integrity assessment of a structure that is produced by friction stir welding with an initial crack

Fracture mechanics aplication on integrity assessment of welded construction made from aluminium alloys

U radu je prikazana praktična primena mehanike loma na nastanak i rast zamornih prslina u konstrukcijama zavarenim primenom frikcionog zavarivanja mešanjem (FSW). Poseban naglasak je dat na tankozidne strukture od legura aluminijuma. Razmatran je rast prsline u neojačanamim i ojačanim konstrukcijama. Pri tome je korišćena numerička metoda bazirana na konačnim elementima - tzv. Proširena Metoda Konačnih Elemenata (PMKE). Analiziran je rast prsline u FSW spoju, kroz zone spoja. Pri tome je korišćen software Abaqus, kao i Morfeo za prikaz dobijenih podataka. Primenjeno je zatezno zamorno opterećenje, pri koeficijentu asimetrije cikusa opterećenja R 0 . Svi modeli su sačinjeni od legure aluminijuma 2024-T351. Karakteristike materijala u zonama spoja, kao i geometrijske mere samog FSW spoja su usvojene iz već postojećih eksperimenata. Razmatrano je više modela: Primer br.:1. najjednostavniji primer ploče, linearno-elastična i elastoplastična analiza. Primer br.:2. dvokomponentna ploča, linearno-elastična i elasto-plastična analiza. Primer br.:3. FSW spoj-2D izložen dejstvu većeg, odnosno manjeg zateznog opterećenja. Primer br.:4. ploča sastavljena od dva FSW spoja izložena dejstvu većeg, odnosno manjeg zateznog opterećenja. Primer br.:5. ploča ojačana sa dva FSW T-spoja izložena dejstvu većeg, odnosno manjeg zateznog opterećenja. Kao rezultati proračuna dobijeni su sledeći podaci: naponsko-deformaciono stanje u konstrukciji, pri čemu je naročita pažnja posvećena zoni u okolini vrha prsline, koordinate tačaka fronta prsline za svaki korak rasta x, y z, raspodela faktora intenziteta napona- I K , II K , III K i ekv K duž fronta prsline za svaki korak rasta, vek konstrukcije u formi promene broja primenjenog ciklusa opterećenja- N za svaki korak rasta prsline. Na bazi dobijenih podataka analizirana je stabilnost širenja prsline kroz strukturu. Takođe, posmatrano je ponašanje linearno-elastičnog i elastoplastičnog materijala. Razmatran je rast prsline iz jedne zone u drugu. Data je uporedna analiza rasta prsline kod neojačanih i ojačanih ploča.In this work aplication of fracture mechanics principels on initiation and growth of fatigue crack in friction stir welded (FSW) strucutres is presented. Special attention is dedicated to thin-walled structures made from aluminum alloys. Crack growth in unstiffened and stiffened construction is considered by using the numerical method based on finite elements - eXtended Finite Element Method (XFEM). Crack growth in FSW joint is analized through all its zones. Thereby is used software Abaqus, as well as Morfeo for results display. Tension fatigue load is applied, with stress intesity ratio R 0 . All analyzed models are made from aluminum alloy 2024-T351. Material properties in joints zones, and geometry mesures of FSW joint are adopded from available experiments. Following examples are analized: Example No.:1. simple plate, analisis in the area of linear-elastics and elasto-plastics. Example No.:2. plate with two regions, analisis in the area of linearelastics and elasto-plastics. Example No.:3. FSW joint-2D, exposed to effect of higher, apropos lower tension load. Example No.:4. plate made of two FSW joints, exposed to effect of higher, apropos lower tension load. Example No.:5. plate stiffened with two FSW T-joints, exposed to effect of higher, apropos lower tension load. Following results are obtain in numerical computations: stress-displacement state in construction, where special attention is dedicated to crack tip zone, points coordinates of crack front x, y z for every progression step, distributions of stress intensity factors- I K , II K , III K i ekv K along crack front for each progressions step, construction life in form of chage of applied load number- N for each step of propagation. On the basis of obtained data, analysis of crack growth stability is made. Also, linear-elastics and elasto-plastics behavior of material is observed. Crack growth from one to another zone is considered. Finally, comparative analisys of crack growth in unstiffened and stiffened plates is made

Practical aspects of fail-safe design - calculation of fatigue life of cracked thin-walled structures

This paper represents fatigue crack growth life prediction in thin-walled structures (plates or shells). There are two analysis results from two different packages of software: NASGRO and FRANC 3D. They are based on Finite Element Method and Linear Elastic Fracture Mechanics principles (LEMF). Moreover, load interaction to crack growth is analyzed. FRANC 3D software is used to compute and display stress-displacement state of structure and simulation of crack fronts progression. Entire work comprises structural integrity assessment

The implementation of 5s tools in sustainable development enterprises with small-scale production

U ovom radu analiziran je Lean alat u analizi održivog razvoja preduzeća sa maloserijskim tipom proizvodnje. Kao polazna osnova upotrebljen je 5S model. Korišćen je primer u procesu finalizacije gotovog transmitera proizvodnje IHMT-CMT-a. Takođe, alalizirani su elementi unapređenja kvaliteta procesa i primene Kaizen filozofije. Značaj rada je samokontrola/samodisciplina zaposlenih na radnom mestu. Na taj način se proces finalizacije proizvoda odvija pravovrmeno, bez otpada i gubitaka, a zaposleni stalno održavaju radno mesto uredno, čisto i funkcionalno.In this paper we analyzed the Lean tool in the analysis of sustainable development of enterprises from smallscale production. 5S model was used as a primary model. It was used for example in the process of finalizing the final transmitter IHMT-CMT production. Also, elements of quality improvement process and implementation of Kaizen philosophy were analyzed. The significance of this work is self-control/self-discipline of employees in the workplace. In this way, the finalization process of the product takes place promptly, without waste and losses, and employees continuously maintain workplace neat, clean and functional

Numerical modelling of crack propagation in friction stir welded joint made of aluminium alloy

In this work, fatigue crack propagation in thin-walled aluminium alloy structure with two friction stir welded (FSW) joints has been numerically modelled. Crack propagation in unstiffened part of the structure between two FSW joints is analyzed. Numerical method, so-called eXtended Finite Element Method (XFEM) has been used, including software Abaqus, as well as Morfeo, for modelling and results display. Tensile fatigue loading is applied, with stress ratio R=0. The analyzed model is made from aluminium alloy 2024-T351. Material properties in joints zones and geometry measures of FSW joint are adopted from available experiments. Following results are obtained by numerical analysis: stress-displacement state in the structure, where special attention is dedicated to the crack tip zone, coordinates of the crack front (x, y, z) for every propagation step, distributions of stress intensity factors - K-I, K-II, K-III and K-eq along the crack front for each propagation step, structural life in form of change of applied number of load cycles, N, for each step of propagation. Besides numerical results, Abaqus provides visualization of crack propagation in the structure. On the basis of obtained data, analysis of crack growth stability is done

Modifikacija i upotreba malogabaritnog transmitera pritiska

In this paper was shown modification of small dimensions pressure transmitter. Modification of the transmitter is a model that provides to improve the manufacturing process. Modification of the IHTM transmitters proved to be a good strategy, the disadvantages are eliminated and the savings obtained the material. Use of this modified transmitter allows the company to achieve good results with small investments.U ovom radu je prikazana modifikacija malogabaritnog transmitera pritiska. Modifikacija transmitera predstavlja model koji obezbeđuje da se unapredi proces proizvodnje. Modifikacija transmitera u IHTM pokazala se kao dobra strategija, nedostaci su eliminisani i dobijena je ušteda na materijalu. Upotreba ovako modifikovanog transmitera omogućava preduzeću da uz manja ulaganja postigne dobre poslovne rezultate

Kutija elektronike – strukturna analiza i izrada

Aditivna proizvodnja pomaže organizacijama da uštede u procesu projektovanja i da smanje troškove realizacije prototipova. U ovom radu analizirana je kutija elektronike. Kućište je modelirano u nekom od 3D softverskih paketa, zatim je urađena strukturna analiza i na kraju je izrađen model na 3D štampaču. Kutija je izrađena od biorazgradivog termoplastičnog materijala PLA. Ideja ovog rada je da se pokaže kako aditivna tehnologija može da zameni konvencionalnu tehnologiju na onim mestima koja nisu kritična i rizična. Strukturna analiza pokazala je da plastično kućište može da izdrži opterećenje od 150 daN. To je važno sa aspekta izrade plastičnog proizvoda umesto metalnog

Designing by CAD application software in order to improve production process

U ovom radu dat je prikaz rešenja koje je projektovano pomoću CAD aplikativnih softvera. Rad je koncipiran da pokaže kakav je značaj upotrebe aplikativnog softvera u domenu: racionalne potrošnje materijala, analize ponovne upotrebe proizvoda i elemenata zaštite životne sredine. U cilju optimizacije celokupnog procesa projektovanja, razvoja i/ili održavanja sistema u različitim granama industrije (gradjevina, mašinstvo). Dakle, posredstvom istih u značajnoj meri se pojednostavljuje: 3D modelovanje kako pojedinačnih mašinskih komponenti, tako i podsklopova i sklopova, izrada prateće 2D tehničke dokumentacija, izrada komponenti na CNC mašinama, proračun čvrstoće, odnosno radnog veka i integriteta konstrukcije. Ključne reči: Proizvod, projektovanje, CAD aplikativni softver, materijal, strategije, zaštita životne sredine.This work contains a display of solutions which is projected using CAD applicable software. The Study is designed to show what is the meaning of usage of applicable software within the following domain: rational consumption of material, analysis of reuse of products and elements of environmental protection, in order to optimize the complete process of designing, development and/or sustaining systems in different industry branches (construction, machinery). Therefore, by means of aforementioned, comes to considerable simplicity of 3D modeling of, forasmuch as individual machinery components, as much as subassemblies and assemblies, creation of following 2D technical documentation, creation of components on CNC machines, forecast of solidity, operating time and construction integrity

Značaj komponenti 3D štampača na ukupan kvalitet izrade modela

Da bi se na 3D štampaču izradio model sa složenim dizajnom odličnog kvaliteta, treba posebnu pažnju posvetiti njegovim elementima. U radu su razmatrana tri fundamentalna elementa: glava štampača, mlaznica i radna podloga. Upravo ovi elementi su odgovorni za ispravan rad uređaja i dalju realizaciju modela. Održavanje i zadavanje parametara štampe u mnogome zavise od stanja uređaja i kvaliteta pripreme elemenata za ukupnu proceduru štampe. Ako kvalitet materijala ne odgovara mogu da se pojave problemi u realizaciji 3D modela. U radu su razmotreni i opisani pomenuti elementi. Ovim radom pokušano je da se sa aspekta kompromisa cene i kvaliteta izrade razmotri uloga vitalnih elementata 3D štampe u realizaciji modela

IoT Game-based Learning Model in Education

The subject of this paper is the development of a game-based learning model based on the Internet of Things (IoT). The main problem discussed in the paper is to investigate the possibility of implementing a game-based learning model in an interactive educational environment that will increase student interest and enhance learning outcomes. The developed model will be based on ubiquitous computing technologies and integrate IoT, mobile, and augmented reality technologies. The proposed model integrates with existing components of the educational infrastructure. As part of the model evaluation, testing and measurement of relevant parameters that affect the effectiveness of the proposed model was carried out