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Numerical analysis of a transtibial prosthesis socket using 3D-Printed Bio-Based PLA
Vasja Plesec, Jani Humar, Polona Dobnik-Dubrovski, Gregor Harih, 2023, original scientific article

Abstract: Lower-limb prosthesis design and manufacturing still rely mostly on the workshop process of trial-and-error using expensive unrecyclable composite materials, resulting in time-consuming, material-wasting, and, ultimately, expensive prostheses. Therefore, we investigated the possibility of utilizing Fused Deposition Modeling 3D-printing technology with inexpensive bio-based and bio-degradable Polylactic Acid (PLA) material for prosthesis socket development and manufacturing. The safety and stability of the proposed 3D-printed PLA socket were analyzed using a recently developed generic transtibial numeric model, with boundary conditions of donning and newly developed realistic gait cycle phases of a heel strike and forefoot loading according to ISO 10328. The material properties of the 3D-printed PLA were determined using uniaxial tensile and compression tests on transverse and longitudinal samples. Numerical simulations with all boundary conditions were performed for the 3D-printed PLA and traditional polystyrene check and definitive composite socket. The results showed that the 3D-printed PLA socket withstands the occurring von-Mises stresses of 5.4 MPa and 10.8 MPa under heel strike and push-off gait conditions, respectively. Furthermore, the maximum deformations observed in the 3D-printed PLA socket of 0.74 mm and 2.66 mm were similar to the check socket deformations of 0.67 mm and 2.52 mm during heel strike and push-off, respectively, hence providing the same stability for the amputees. We have shown that an inexpensive, bio-based, and bio-degradable PLA material can be considered for manufacturing the lower-limb prosthesis, resulting in an environmentally friendly and inexpensive solution.
Keywords: 3D printing, bio-based, polylactic acid, PLA, prosthesis, prosthesis socket, numerical model, finite element method
Published in DKUM: 14.03.2024; Views: 118; Downloads: 21
.pdf Full text (5,99 MB)
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3.
Computer modelling of the residual limb for the development of prosthetic sockets and liners with the cellular structure : doctoral disertation
Vasja Plesec, 2023, doctoral dissertation

Abstract: The production of lower limb prostheses continues to rely primarily on manual methods, which are outdated and characterized by labour-intensive processes, lengthy time requirements, high costs, and a heavy reliance on the expertise of prosthetists. Achieving a satisfactory fit between the residual limb and socket remains a challenge, often leading to discomfort, pain, and potential wearer tissue damage. However, advancements in computer technology and numerical simulation offer an opportunity to predict stresses and strains experienced by the residual limb during prosthesis usage. This, in turn, aids in the development process by enhancing the design of the prosthetic socket and liner through virtual environments. In this dissertation we developed a generic numerical transtibial model to bridge the gap between clinical practice and numerical simulations. Biomechanically validated, this model generates outcomes applicable to a broader amputee population, facilitating comparative analysis of socket and liner designs and materials under different loading conditions. Furthermore, the dissertation explores the utilization of a 3D-printed socket manufactured through the cost-effective fused filament fabrication process, using polylactic acid filament, aiming to reduce the costs and establish a streamlined production process. The 3D-printed socket was evaluated within the virtual environment using the developed transtibial model. The numerical findings indicate that the 3D-printed socket can effectively withstand the loads encountered during the stages of prosthesis donning, single-leg stance, heel strike, and push-off, thereby presenting a viable alternative to the prevalent composite socket. Additionally, a cellular structure composed of a flexible thermoplastic elastomeric material is proposed as a prosthetic liner to enhance comfort by reducing contact pressure while maintaining the required stability. Numerical results indicate that by manipulating cellular parameters such as unit cell type and relative density of the structure, a customized response can be achieved. This customized response effectively reduces contact pressure for a given scenario without increasing displacement, thereby improving comfort while maintaining stability.
Keywords: lower-limb prosthesis, generic numerical transtibial model, 3D-printed socket, cellular structure liner, finite element method
Published in DKUM: 14.11.2023; Views: 540; Downloads: 33
.pdf Full text (3,64 MB)

4.
Implementacija realno-časovne komunikacije v aplikaciji intrix : diplomsko delo
Kristian Šic, 2023, undergraduate thesis

Abstract: Diplomsko delo opisuje implementacijo realno-časovne komunikacije v platformi Intrix z uporabo knjižnice Socket.io. Najprej predstavljamo tehnologije, ki nam omogočajo realno-časovno komunikacijo, ki so trenutno na voljo, ter primerjamo njihove prednosti in slabosti. Nato opisujemo potek implementacije realno-časovne komunikacije v platformi Intrix in načrtovanje strežnika za realno-časovno komunikacijo. Predstavljamo tudi rezultate preizkusa izjemnih situacij ter ugotovitve analize o varnosti in možnih razširljivostih implementiranega sistema. Na koncu smo prikazali še izboljšave v uporabniški izkušnji ob uporabi aplikacije Intrix po implementaciji realno-časovne komunikacije.
Keywords: Intrix, ogrodje Vue.js, spletna aplikacija, realno-časovna komunikacija, Socket.io
Published in DKUM: 24.04.2023; Views: 497; Downloads: 93
.pdf Full text (3,83 MB)

5.
Izdelava spletne interaktivne učilnice
Uroš Čeh, 2017, undergraduate thesis

Abstract: Spletne tehnologije pridobivajo ključno vlogo na področju izobraževalnega sistema. V sklopu izobraževanja na daljavo postajajo vse bolj popularne virtualne učilnice, ki uporabnikom ponujajo interaktivno učno okolje podobno tradicionalnim učilnicam. V diplomskem delu smo najprej preučili sodobne sklade tehnologij in tehnike realnočasovne komunikacije na spletu. S pridobljenim znanjem smo nato izdelali spletno interaktivno učilnico, ki s pomočjo interaktivne table ali video konference omogoča uporabnikom učenje na daljavo. V sklopu testiranja aplikacije smo opravili meritve knjižnice Socket.IO in vmesnika WebRTC in ugotovili, da so izbrane tehnologije zelo primerne za izdelavo spletnih in mobilnih realnočasovnih aplikacij.
Keywords: interaktivna učilnica, Socket.IO, WebRTC, MEAN, realnočasovna aplikacija
Published in DKUM: 30.08.2017; Views: 1643; Downloads: 121
.pdf Full text (2,77 MB)

6.
ZAGOTAVLJANJE VARNOSTI V REŠITVAH, KI TEMELJIJO NA TEHNOLOGIJAH HTML5
Jernej Mušič, 2016, master's thesis

Abstract: V magistrski nalogi smo si ogledali varnostne ranljivosti standarda HTML5 ter načine, kako preprečiti takšne napade s pomočjo mehanizmov za zagotavljanje varnosti v standardu. Analizirali smo temeljne nove funkcionalnosti in njihovo implementacijo ter kakšne so njihove zmožnosti in iskali točke, kjer bi lahko napadalec potencialno ogrožal spletno aplikacijo, ki ta element uporablja. S pomočjo literature smo tudi poiskali omenjene vektorje, ki omogočajo varnostne vdore in načine, kako te vdore preprečiti in ali so učinkoviti. Ugotovili smo, da je standard HTML5 dopolnjen z varnostnimi predlogi za razvijalce, vendar obstaja preveč nerešenih varnostnih vprašanj, ki bi označevali ta standard kot ustreznega za razvoj varnostno kritičnih aplikacij.
Keywords: Varnost, HTML5, Web socket, Canvas, Vrivanje SQL
Published in DKUM: 05.07.2016; Views: 1373; Downloads: 173
.pdf Full text (2,89 MB)

7.
RAZVOJ MODULA ZA INTERAKTIVNI PRIKAZ LOKACIJE OBJEKTOV NA SVETOVNEM SPLETU S 3D GRAFIKO
Luka Škerjanec, 2015, bachelor thesis/paper

Abstract: Tema diplomskega dela je razvoj modula za prikaz in upravljanje 3D objektov preko svetovnega spleta s pomočjo strojnega vmesnika za potrebe interaktivnega grafičnega prikaza lokacije. Rešitev omogoča interaktivni 3D prikaz v spletnem pregledovalniku. Razvoj rešitve je potekal na strežniku z nameščenim operacijskim sistemom Ubuntu 12.04 LTS, na katerega je povezan mikrokontroler Arduino Uno in potenciometri kot manipulatorji lokacije. Mikrokontroler Arduino Uno, na katerega so priključeni ustrezni vhodni elementi, služi za zajem podatkov, ki jih pošilja na strežnik. Na strežniku smo s pomočjo programskega jezika JavaScript ter tehnologije Node.js ter HTML razvili spletno stran, ki služi za izrisovanje 3D predmetov v okolju. Spletna stran omogoča prikaz/izpis podatkov, prejetih s strani mikrokontrolerja ter simulacijo disperzije polutantov, ki jo lahko poljubno manipuliramo.
Keywords: 3D grafika, Arduino, Node.js, JavaScript, Firmata, Three.js, socket.io, kiberfizični sistem, Internet stvari
Published in DKUM: 25.08.2015; Views: 1769; Downloads: 141
.pdf Full text (1,19 MB)

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