Blar i UiS Brage på forfatter "Lemu, Hirpa G."
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Experimental investigation and ANN prediction for part quality improvement of fused deposition modeling parts
Tura, Amanuel; Mamo, Hanna; Jelila, Yohannis; Lemu, Hirpa G. (Peer reviewed; Journal article, 2021)Fused deposition modeling (FDM) is the most prevalent thermoplastic additive manufacturing technology. Many input parameters and their settings have a significant impact on the quality and functionality of FDM parts produced. ... -
Experimental Investigation on Effect of Weight Fraction of Sisal Fiber on Mechanical Properties of Sisal-E-Glass Hybrid Polymer Composites
Gurmu, Debela N.; Lemu, Hirpa G. (Peer reviewed; Journal article, 2023)Currently, hybridizing natural fibers with synthetic fiber is considered as the best solution for reducing the environmental pollution and the cost of materials. This is due to the lower mechanical properties and high water ... -
Experimental study of physical, chemical and mechanical properties of enset and sisal fibers
Bekele, Abera E.; Lemu, Hirpa G.; Jiru, Moera G. (Peer reviewed; Journal article, 2021)The properties of composites depend on type and properties of the fiber, fiber structure and treatment. In this study, effects of NaOH treatment on the physical, chemical and mechanical properties of fibers collected from ... -
Fatigue life analysis of wheel-rail contacts at railway turnouts using finite element modelling approach
Jelila, Yohanis D.; Lemu, Hirpa G.; pamula, Wiesław; Sirata, Goftila (Peer reviewed; Journal article, 2021)The article deals with wheel-rail contact analysis at railway turnout using a finite element modelling approach. The focus is understanding the wheel-rail contact problems and finding the means of reducing these problems ... -
FEM-based assessment of wear of stamping die
Trzepiecinski, Thomasz; Lemu, Hirpa G. (Peer reviewed; Journal article, 2019)In sheet metal forming industry, surface damage and wear such as adhesion and ploughing of metallic sheet, is a well-known problem which reduces the tool life and quality of drawn elements. Surface defects are the consequences ... -
Finite element method-based modeling of bending under tension friction test of deep drawing quality steel sheets
Trzepiecinski, Thomasz; Lemu, Hirpa G. (Peer reviewed; Journal article, 2019)Understanding of the effect of the friction on the sheet deformation is a key factor in design and realization of stamping process. Among others, bending under tension friction test simulates the frictional phenomena on ... -
Finite Element Modelling and Analysis of Axial Settlement of Light Poles
Rasmussen, Simen (Masteroppgave/UIS-TN-IMBM/2020;, Master thesis, 2020)The slip joint technology is a method for connecting two conical pole segments together, without the use of bolts or grout, thus reducing time of installation and the need of maintenance. In recent years there have been ... -
Friction modeling of Al-Mg alloy sheets based on multiple regression analysis and neural networks
Lemu, Hirpa G.; Trzepieciński, Tomasz; Kubit, Andrzej; Fejkiel, Romuald (Journal article; Peer reviewed, 2017-03)This article reports a proposed approach to a frictional resistance description in sheet metal forming processes that enables the determination of the friction coefficient value under a wide range of friction conditions, ... -
Improving Prediction of Springback in Sheet Metal Forming Using Multilayer Perceptron-Based Genetic Algorithm
Trzepiecinski, Thomasz; Lemu, Hirpa G. (Peer reviewed; Journal article, 2020)This paper presents the results of predictions of springback of cold-rolled anisotropic steel sheets using an approach based on a multilayer perceptron-based artificial neural network (ANN) coupled with a genetic algorithm ... -
Influence of 3D Printing FDM Process Parameters on Tensile Property of ULTEM 9085
Gebisa, Aboma Wagari; Lemu, Hirpa G. (Peer reviewed; Journal article, 2019)3D printing is a promising digital manufacturing technique that produces parts, layer by layer. Fused deposition modeling (FDM) is a widely employed 3D printing technology that produces components by heating, extruding and ... -
Investigating Effects of Fused-Deposition Modeling (FDM) Processing Parameters on Flexural Properties of ULTEM 9085 using Designed Experiment
Gebisa, Aboma Wagari; Lemu, Hirpa G. (Journal article; Peer reviewed, 2018-03)Fused-deposition modeling (FDM), one of the additive manufacturing (AM) technologies, is an advanced digital manufacturing technique that produces parts by heating, extruding and depositing filaments of thermoplastic ... -
An investigation of the effects and consequences of combining Expanding Dual Pin with radial spherical plain bearings
Karlsen, Øyvind; Lemu, Hirpa G.; Berkani, Imad (Peer reviewed; Journal article, 2022)An expanding pin locks the pin assembly to its supports and bearings and prevents any relative movements between the surfaces in contact. In this study, the diameter changes of the bearing inner ring as a function of the ... -
Kinematic Modeling and Analysis of a Walking Machine (Robot) Leg Mechanism on a Rough Terrain
Terefe, Tesfaye O.; Lemu, Hirpa G.; K/Mariam, Addisu; Tuli, Tadele B. (Peer reviewed; Journal article, 2019-07)Many manmade machines and mechanisms including robots function based on the concept of nature-inspired design so that they can perform their intended duties by mimicking the working mechanisms of animals and insects. ... -
Literature Review on Thermomechanical Modelling and Analysis of Residual Stress Effects in Wire Arc Additive Manufacturing
Gurmesa, Fakada Dabalo; Lemu, Hirpa G. (Peer reviewed; Journal article, 2023-03)The wire arc additive manufacturing (WAAM) process is a 3D metal-printing technique that builds components by depositing beads of molten metal wire pool in a layer-by-layer style. Even though manufactured parts commonly ... -
Literature review on thin-walled and cellular structure designs for energy absorption
Dabasa, Tamana; Lemu, Hirpa G.; Regassa, Yohannes (Peer reviewed; Journal article, 2023)Bio-inspired structure is a topic of immense interest to researchers worldwide. In order to maximize energy absorption through biomimetic structures, this article presents bio-inspired structure particularly, thin walled ... -
Mechanical property characterization of water hyacinth and glass fiber reinforced hybrid composite
Tewelde, Samrawit A; Lemu, Hirpa G.; Dawit, Jonathan B (Peer reviewed; Journal article, 2022)While composites of natural fibers have got more attraction because of their advantages, there are some limitations. Therefore, hybridization is a way to minimize some of the limitations of natural fibers composite. This ... -
Modeling Thermomechanical Stress with H13 Tool Steel Material Response for Rolling Die under Hot Milling
Tolcha, Mesay Alemu; Lemu, Hirpa G. (Peer reviewed; Journal article, 2019)For the extreme pressure and temperature arising in the hot rolling process, thermomechanical (TM) models are used to predict the residual stresses on the surface of the die because a quantification of the TM stresses ... -
Modifikasjon og resultattesting av filamentekstruder for 3D printing
Xia, Jia Wei Haakon (Bachelor thesis, 2021) -
Multiphysics Modeling and Numerical Simulation in Computer-Aided Manufacturing Processes
Trzepiecinski, Tomasz; dell’Isola, Francesco; Lemu, Hirpa G. (Peer reviewed; Journal article, 2021)The concept of Industry 4.0 is defined as a common term for technology and the concept of new digital tools to optimize the manufacturing process. Within this framework of modular smart factories, cyber-physical systems ... -
New Advances and Future Possibilities in Forming Technology of Hybrid Metal–Polymer Composites Used in Aerospace Applications
Trzepieciński, Tomasz; Najm, Sherwan M; Sbayti, Manel; Belhadjsalah, Hedi; Szpunar, Marcin; Lemu, Hirpa G. (Peer reviewed; Journal article, 2021-08)Fibre metal laminates, hybrid composite materials built up from interlaced layers of thin metals and fibre reinforced adhesives, are future-proof materials used in the production of passenger aircraft, yachts, sailplanes, ...