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Post
Extruded aluminum decks for pedestrian bridges Design optimization using genetic algorithm
(2023) FALKENBERG, EMELIE; FREDRIKSSON, MARKUS; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Al-Emrani, Mohammad
Material efficiency in bridge structures is an important research topic to reduce the
climate footprint and initial costs. One way of increasing material efficiency is to
use appropriate materials where their properties benefit the structure. Aluminium
offers a high stiffness-to-weight ratio, high durability, and is to a large degree re cyclable. These properties make aluminium an interesting material for bridge deck
applications.
The initial cost of the bridge deck has high priority amongst bridge authorities
in Europe. To minimize the initial cost, one target is to minimize material con sumption. This thesis aims to develop an optimization procedure with the objective
to minimize the material consumption of extruded aluminium profiles for pedestrian
bridge deck applications. In the design of the deck, requirements stated in Eurocode
are followed. The optimization is made using a genetic algorithm function from the
global optimization toolbox in the software MATLAB. Cross-sectional geometries
generated by the optimization procedure was evaluated separately by the imple mentation of a FE-module. The FE-module is controlled by parameterized Python
scripting to create a FE-model and execute an analysis in the software ABAQUS
CAE for each iteration.
The optimization provided a cross-sectional geometry for the bridge deck. These
results were used for a cost comparison between the optimized cross-section and
more conventional alternatives in C-Mn and duplex steel. The comparison showed
that the weight per square meter of the resulting optimized profile was significantly
lower compared to the deck alternatives in steel. It also showed that saving from 8%
up to 27% can be made on the initial investment cost if choosing aluminium instead
of a conventional deck alternative in stainless steel. Thus, aluminium is shown to
be a potential alternative to steel.
Post
Effective Testing: Analysing and tackling challenges in production testing of industrial machines Master’s thesis in Production Engineering PHILIP LEES
(2023) Lees, Philip; Chalmers tekniska högskola / Institutionen för industri- och materialvetenskap; Chalmers University of Technology / Department of Industrial and Materials Science; Bergsjö, Dag; Haag, Simon
This thesis aims to study the barriers affecting effective testing and setup of print
and apply machinery, and how these barriers can be overcome. Based on theoretical
foundation of quality, testing, production concepts (Product Lifecycle Management,
Industry 4.0 etc.) and production engineering, and methodologies such as design
research methodology, observation, time study, process mapping and ergonomics,
results found indications of barriers within testing. These indications show that
while test technicians are able to identify and rectify quality issues, more support to
perform more effective testing is desired. Further analysis showed that specification
definition, information flow, standardisation and documentation are specific areas
where barriers for effective testing could be identified. A number of practical rec ommendations based on concepts such as Product Lifecycle Management, Industry
4.0 and checklist design are proposed. These are designed to leverage digitalisation
and knowledge management in order to overcome the barriers discussed.
Post
Investigating and developing a user-friendly interface for a DLP 3D bioprinter
(2023) Eriksson, Alice; Petri, Amanda; Chalmers tekniska högskola / Institutionen för industri- och materialvetenskap; Chalmers University of Technology / Department of Industrial and Materials Science; Rexfelt, Oskar; Rexfelt, Oskar
The project investigates a light-based 3D bioprinter from a user point of view. It aims at finding how
the current functionality and interface is perceived, what future functionalities are desired and how the
interface could be improved. This should result in two deliverables. Firstly, a needs and desires list
based on user insights and theoretical investigation. Secondly, a redesign of the current interface based
on the needs and desires list that take aesthetic inspiration from the company’s existing software for
extrusion-based printing.
The bioprinter was investigated by observations, presentations, and theoretical evaluations. User
insights were found through interviews with the primary user group, researchers within the medical
field. Through these investigations and interviews, input was given on how the printer operates and
what future functionality is wanted. With the product interface, three overarching goals were in focus
for the redesign. The first goal was to improve the interface architecture, by having a consistent layout
based on functional hierarchy. The second goal was to create a more touch friendly interface, and the
last goal was to provide a design with high visual clarity. Apart from these interface improvements,
new functionality was added to the redesign, for example expanding the interface compatibility to a 96
well plate and providing 3D model navigation.
Design suggestions were created through iterations and evaluations with company experts throughout
the design creation which helped the project create an interface that met the needs and desires. The final
design combines concepts on different interactions needed to solve a setup process that suits current
and future functionalities
Post
From waste to wardrobe A comparative life cycle assessment on prolonging garment lifetime through repair and online second-hand
(2023) Collin Aronsson, Klara; Jagefeldt, Johanna; Chalmers tekniska högskola / Institutionen för teknikens ekonomi och organisation; Chalmers University of Technology / Department of Technology Management and Economics; Ljunggren, Maria; Jerome, Adeline
The clothing industry, encompassing all its activities from production to end-of-life, is
a major contributor to environmental damage. The global production and consumption
of clothes have roughly doubled in the past 15 years and fast fashion, with short garment
lifecycles, intensifies the resource demand and the ensuing emissions. As a response, a shift
from the traditional linear model of take-make-dispose to circularity can be seen through
clothing companies working with circular business models (CBMs) or implementing circular
strategies. Understanding the environmental impact of these circular initiatives is crucial
for reducing the overall environmental footprint of clothing.
The aim of the thesis was to assess the environmental impact of prolonging a pair of pant’s
lifetime through two CBMs based on circular strategies or business models represented on
the Swedish market and comparing it to the linear model. This was done by a mapping
of Swedish clothing companies to select two either circular strategies or CBMS to serve
as the foundation for the proposed models. Two general CBMs, one based on repair and
one on an online second-hand (OSH) platform, were created, derived from information
from interviews and literature. The environmental impact of the models was evaluated by
conducting a life cycle assessment, and a sensitivity analysis was performed to assess the
robustness of the results.
The study found that companies are embracing circularity, either through CBMs or by
implementing circular strategies such as physical and online second-hand, repair, exchange,
and rental services. It was also shown that by extending a pair of pants’ lifetime through
CBMs based on repair or OSH, the environmental impact per garment lifetime is reduced
compared to the linear model. It was found that repair resulted in the lowest impact due
to the significant increase in the number of enabled uses and the relatively small impact
from the repairing process, despite a large impact from additional consumer car transports.
OSH was also found to be preferable to the linear model. The additional processes required
by OSH, i.e. truck transports and sorting and managing of the pants had a relatively low
environmental impact and the CBM enabled more uses of the pants than the linear model
achieved. However, OSH enabled fewer uses compared to repair, which made it fall between
the linear model and repair in terms of overall impact. Lastly, it was also found that the
potential of both repair and OSH is mainly dependent on consumers’ transportation modes
and distances, and the actual number of achieved uses.
The study shows the importance for consumers to fully utilize purchased garments and to
consider repairing them instead of buying new ones when they are worn out. When consid-
ering selling or donating their clothes, the study also shows the importance of only doing
so if the garments are undamaged and of good quality to avoid additional transportation
and waste creation that could ensue if the receiving company should deem the clothes unfit
for resale. This, as general consumer behavior, would result in an overall reduction in the
demand for the production of new clothing. Furthermore, the study shows that the con-
sumers’ choice of transportation mode and ability to combine errands is of big importance
to the overall efficiency and impact of the CBM.
Post
Identification of critical pipes in a drinking water distribution system
(2023) BRANDÉN, JONATAN; Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Chalmers tekniska högskola / Institutionen för arkitektur och samhällsbyggnadsteknik (ACE); Wilén, Britt-Marie
The aim of this master thesis is to identify the most critical pipes in a drinking water
distribution system through hydraulic modelling. The criticality of a pipe will be
based on the consequences of pipe breakage including the affect on the supply of
valuable users.
Reliability will be seen as the ability to supply the quantitative demand
to the households and valuable users at any time and to identify the criticality of
a pipe, the pipe´s contribution to the system reliability has been evaluated. The
contribution are estimated by evaluating the results from hydraulic simulation of
the drinking water system, without the investigated pipe. Four indices, demand,
affected users, time and valuable user index as well as a gathered criticality index
are used to estimate the reliability of a drinking water system.
To give more substance of the identification of critical pipes the reliability
requirements of a drinking water distribution system could be further evolved. When
determining the criticality of the pipes in the system, one key aspect is how pipes
with different patterns should be compared between each other. Pressure driven and
demand driven approach gave the same results for the majority of the pipes and a
risk-based approach including probabilities would give a more in depth analysis of
the criticality.