| 12391. |
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| 12392. |
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| 12393. |
- Lalit, Manan, 1988, et al.
(författare)
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Surface non-conformances on the low pressure turbine outlet guide vane flow
- 2010
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Ingår i: 27th Congress of the International Council of the Aeronautical Sciences 2010, ICAS 2010; Nice; France; 19 September 2010 through 24 September 2010. - 9781617820496 ; 4, s. 2851-2859
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Konferensbidrag (refereegranskat)abstract
- During manufacturing and in-service of the outlet guide vanes various irregularities on the vane surface can occur. These irregular shapes are surface non-conformances in the form of welds, traces or repairs of various forms. Improvement of the aerodynamic performance of the guide vanes requires understanding of the impact of these technological features on the flow field and aerodynamics. Experimental study is performed in a linear cascade facility at Chalmers University. In focus of current work are non-conformances in form of welding traces. The model welding traces were placed at different locations on the suction side of the vane. The influence of these non-conformances on the cascade aerodynamics is evaluated and validation of CFD results obtained by the k-ε realizable and k-ω SST turbulence models is performed.
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| 12394. |
- Lamy, Michael, et al.
(författare)
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Traumatic Brain Injury Investigation Using FE Modeling of the Rat and Experimental High Amplitude Rotations in the Sagittal Plane
- 2013
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Ingår i: IRCOBI Conference. - 2235-3151. ; :IRC-13-51, s. 456-469
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Konferensbidrag (refereegranskat)abstract
- A combined approach of numerical modeling and animal experiments was used to study themechanisms of traumatic brain injury (TBI). A three‐dimensional finite element model (FEM) of the rat brainwas submitted to experimental sagittal plane rotational acceleration pulses. The experimental setup providedhistological analysis of injured brain tissues for a range of severities. The biomechanical response parameterswere extracted from the FEM in the anatomical regions identified by experiments as prone to injuries. VonMises stresses and first principal strains proved to increase with both the amplitude of acceleration loadings andthe tissue injuries severities. Further comparison between mechanical responses and experimental histologicalscores allowed proposing tissue thresholds for the occurrence of TBI, namely 1.5 kPa and 4% approximately forVon Mises stresses and first principal strains, respectively. Those values can be used for further investigationsof the mechanisms of TBI.
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| 12395. |
- Landahl, Jonas, 1986, et al.
(författare)
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Assessing Producibility of Product Platforms Using Set-Based Concurrent Engineering
- 2016
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Ingår i: Advances in Transdisciplinary Engineering. - 2352-751X .- 2352-7528. - 9781614997030 ; 4, s. 35-44
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Konferensbidrag (refereegranskat)abstract
- This paper presents a method to facilitate model-based producibility assessments of product variants in the early phases of platform development. The approach uses set-based concurrent engineering principles to explore and narrow down a design space towards feasible alternatives. A case including tool accessibility and assembly robustness of an aerospace sub-system platform is used to demonstrate the approach. The assessment activities can be prepared in parallel, and support the concurrency needed, across design and manufacturing, to serve improved process efficiency. Ultimately, the approach may reduce late design modifications thanks to increased reuse of manufacturing knowledge, as well as reduce cost thanks to less physical prototyping and testing.
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| 12396. |
- Landahl, Jonas, 1986
(författare)
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Development of Interdisciplinary Platforms Using System Objects
- 2016
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Conceptually “form follows function”, as stated by Louis Sullivan. Physically however, form follows producibility.There is an erroneous notion that many customers can be provided with customized products, produced without any battle. In reality however, behind the walls of manufacturing companies, there is a constant struggle to combine the functionality and performance of complex products, while taking knowledge from manufacturing into account.Thankfully, there are a few shortcuts upon which manufacturing companies can capitalize. One of them is design reuse, i.e. there are elements of existing products and processes that can be reused in designing new products. Such elements do not have to be physical items. They can, for example, be laws of physics, mechanical properties, or known limitations of a manufacturing process. The use of platforms has proven efficient for design reuse. Platforms can accommodate product families, rather than a single product. By using platforms, common elements can be shared among the products in a family. Such design reuse has the potential of reducing development cost and make the development process more efficient.However, when developing a family of products, the evaluation of performance and producibility of multiple design alternatives becomes even more challenging, compared to that of a single design. Thus, to overcome this challenge, a platform development methodology is proposed to support the creation and evaluation of multiple design alternatives. First, we need to gather and store knowledge about similar products. Secondly, we need to be able to generate a family of design alternatives, and to somehow rank the family of alternatives by their feasibility. Thereafter, the inferior alternatives can be eliminated, and the good alternatives can form the basis for further development.Based on several industrial studies, the methodology has been developed to support modeling of known designs, generate several new alternatives, evaluate them and eliminate the bad ones. The methodology provides design engineers and system architects with the methods and tools needed to make credible design decisions early in platform development. The methodology builds on existing theoretical models, methods and tools, and describes platform system objects that support design reuse. The methodology serves three development levels, reflecting the level of design detail of the product family: 1) functional level; functions and alternative ways of solving them, 2) system level; system objects with design parameters, and 3) detailed level; conceptual 3D shapes. The three levels can be used iteratively, as the platform matures throughout the development process.The aim is to support design engineers and system architects in developing platforms for the early phases of development, and provide them with the basis for harmonizing between product performance and manufacturing capabilities, partly to reduce late and costly design modifications due to inferior producibility of products, but also to be prepared for future demands by accommodating the needs of a range of customers rather than a single customer.
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| 12397. |
- Landberg, Magnus, et al.
(författare)
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NOVEL LINEAR HYDRAULIC ACTUATOR
- 2015
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Ingår i: PROCEEDINGS OF THE ASME/BATH SYMPOSIUM ON FLUID POWER AND MOTION CONTROL, 2015. - : ASME Press. - 9780791857236
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Konferensbidrag (refereegranskat)abstract
- In the area of linear motion, infinite stroke only is provided by electric actuators today, until now there has been no hydraulic alternative. The novel linear hydraulic actuator consists of two double acting cylinders with a common piston rod. The working principle of this actuator for short movements is that at least one piston is connected to the piston rod and the actuator works like an ordinary hydraulic double acting cylinder. For longer movements one of the pistons is connected alternatively to the piston rod providing the drive. In this way the two pistons are moving the piston rod alternatingly in a kind of rope climbing motion. The critical element is the clamping mechanism which is an already known machine element but used in this new application. Advantages of this concept are as follows: The actuator is compact. Very long strokes and piston rods are allowed without side effects of common cylinders. This property is the origin of the name "infinite cylinder". The cylinder has small chamber volumes and so high hydraulic stiffness and low capacitance. It has also potentially no external leakage. The cylinder can provide twice the rated force for short strokes. Applications for this feature are the plate opening stroke of injection molding machines, or presses with low work to travel stroke ratio, like a press brake. The paper includes a detailed description of the design and the working principle. One critical component is the clamping mechanism which temporarily connects the pistons to the piston rod. The clamping mechanism together with the piston represents a new kind of machine element in the mechanical engineering field. Here the focus will be on the function and the control strategy. With simulation the proposed control strategy and function will be presented and the performance analyzed. The simulation model is backed up by first results from experiments on the early prototype. The experiments carried out so far on the hydraulic clamping mechanism, which is the critical component in the system show very promising results that the required function can be achieved. Furthermore, the function of the whole cylinder has been simulated with good result. For the full paper results from a functioning prototype is also to be expected.
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| 12398. |
- Landberg, Magnus, et al.
(författare)
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The Hydraulic Infinite Linear Actuator with Multiple Rods
- 2017
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Ingår i: Proceedings of 15:th Scandinavian International Conference on Fluid Power, June 7-9, 2017, Linköping, Sweden. - Linköping : Linköping University Electronic Press. - 9789176853696 ; , s. 279-293
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Future hydraulic actuation systems can be significantly improved by utilisation of a new type of hydraulic linear actuator technology. By enabling multiple actuating elements, integrated in a compact and lightweight single unit controlled by ordinary directional valves it is possible to achieve a high position accuracy. This is a new way to generate and distribute mechanical linear movement and force by using hydraulic actuators in a cost effective way, in less responsive closed loop systems. This is a variant on the Hydraulic Infinite Linear Actuator, HILA, invention. The technology also represents a new sort of digital hydraulics. The presented technology provides typical hydraulic actuator characteristics with high system pressure and potentially no external oil leakage. It is based on a well-known hydraulic clamping element technology used in a new way, where the piston and the piston rod can quickly be coupled and uncoupled by means of the clamping element in a failsafe way by using well defined incremental steps. HILA in its simplest usage, provides new features to hydraulic cylinders such as providing very long strokes, high rod speed, and small chamber volumes which means high stiffness and low capacitance. The aim of this study is to present a fundamentally new way of using hydraulic actuators. The invention is called the Hydraulic Infinite Linear Actuator with Multiple Rods, HILA MR. The study presents the idea, principles and feasible combinations of the technology. Also applications in the aircraft and robotic field will be presented.
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| 12399. |
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| 12400. |
- Landqvist, Hans, 1958, et al.
(författare)
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Intresse och engagemang: Kungliga Tekniska högskolans insatser i ett svenskt terminologiskt nätverk 1941–1983 : Interest and involvement: the contributions of the Royal Institute of Technology to a Swedish terminological network 1941–1983
- 2021
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Ingår i: Folkmålsstudier Meddelanden från Föreningen för nordisk filologi. - 0356-1771. ; 59, s. 103-133
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we study how KTH Royal Institute of Technology (Kungliga Tekniska högskolan – KTH) has participated in and influenced terminology work coordinated by the national terminology centre, the Swedish Centre for Technical Terminology – the TNC, in Sweden during the period 1941–1983. The aim of this paper is to shed light on the development of Swedish (technical) terminology based on networking and experts’ efforts. Based on archive material, we analyze who have been the active KTH experts, in what ways they were involved in the development processes and what effects their efforts had on the term recommendations given by the TNC. The archive material consists of written documents relating to the work process developed by John Wennerberg, who led the TNC between 1941 and 1957. The process was carried out in the form of 373 formal survey letters representing 17 subject fields, with both the TNC and external parties participating. Our results show that the 31 identified KTH experts play a visible role in the processes by 480 received survey letters within 14 subject fields. The response rate, 80 percent, reveal the experts’ involvement in the process and their high esteem of TNC’s work. The analysis of the comprehensive survey letter R198 shows that Wennerberg has considered the experts’ answers regarding terms (selection, linguistic form, acceptance/discourage) and definitions when he has published TNC’s recommendations. Our study shows that networking and experts representing the educational sector and furthermore universities have been an inseparable part of the development of Swedish (technical) terminology during several decades when the national terminology centre in Sweden began to operate and the working methods were established.
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