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- Återtagning av små fastvingsdrönare i sjöräddningsmiljöBergman, AndreasThis thesis work was conducted in collaboration with Sjöräddningssällskapet (SSRS), which utilizes unmanned aerial vehicles (UAVs) to support maritime rescue operations. In coastal environments with small landing space and variable wind conditions, conventional landing methods for fixed-wing UAVs are not always suitable. The objective of this project was therefore to develop a conceptual system for safe mid-air capture and retrieval of a small fixed-wing UAV adapted to SSRS operational requirements. The work followed a structured product development process. After establishing system requirements and performing a functional analysis, solution principles were generated using a morphological matrix. Partial solutions and overall concepts were reduced through a systematic elimination process, excluding technically unsuitable or impractical alternatives. The remaining concepts were further analysed with respect to energy absorption, feasibility, and operational applicability. The final concept consists of a portable, modular capture system based on mechanical energy absorption through a tensioned line between two interconnected units. The system is dimensioned according to the UAV’s kinetic energy at approach, enabling a compact design compared to large-scale commercial systems. Analytical calculations indicate that the concept is feasible at a conceptual level and capable of handling the expected loads. The study demonstrates that an established capture principle can be scaled and adapted to maritime rescue applications through systematic concept development. Future work should include prototype development and experimental validation under realistic operating conditions.
- Linjärt eller cirkulärt installationselement? Livscykeltänkande i praktiken(2026) Meherdel, Najib; Naggar, RaniKlimatförändringarna är en av vår tids största globala utmaningar. För att bromsa utvecklingen och minska utsläppen av växthusgaser har Europeiska unionen (EU) tagit fram en omfattande klimat- och miljöpolitik. I centrum för omställningen står den europeiska gröna given som har som mål att EU ska bli klimatneutralt senast 2050 (EU-kommissionen, 2023). Ett viktigt verktyg är livscykeltänkande som är ett tankeverktyg för att utvärdera produkter och tjänsters miljöbelastning och en utgångspunkt för cirkulärekonomi. I en cirkulärekonomi förväntas produkter, material och resurser cirkulera länge i produktionssystemen genom att återanvändas, repareras och återvinnas. (Naturvårdsverket, 2023). Byggsektorn har en särskilt stor påverkan på både klimat och resurser. Den kallas ofta för 40% branschen, skapar 40% avfall, använder 40% av energin och använder 40% av materialen. I Sverige står byggbranschen för omkring 22 procent av växthusgasutsläppen och producerar ungefär en tredjedel av allt avfall (Boverket, 2025). Här spelar tekniska installationer, som ventilation, VVS och el, en nyckelroll. Systemen byts ofta ut flera gånger under en byggnads livslängd, men är i dag sällan utformade för att kunna återbrukas eller återvinnas effektivt. Syftet med studien är att analysera hur produkterna kan miljöanpassas, med målet att identifiera möjliga designförändringar som underlättar framtida reparationer, demontering och återanvändning. För att nå detta syfte har en kvalitativ intervjustudie genomförts med intressenter som på olika sätt är involverade i produktlivscykeln exempelvis tillverkarföretag, teknikkonsulter och fastighetsförvaltare. Studien är avgränsad till aktörer verksamma inom byggbranschen i Göteborgsregionen, vilket ger ett lokalt perspektiv på både utmaningar och möjligheter i den cirkulära omställningen. En viktig slutsats från studien är att många installationselement i dag är utvecklade för ett linjärt användande, där produkterna används en gång och sedan kasseras. Det gör det svårt att demontera dem utan att de skadas, samtidigt som det ofta saknas tydlig dokumentation om vilka material som ingår. För att skapa cirkulära system behöver LCT (livscykeltänkande) tillämpas
- Structural Investigation of an Alternative Cordwood Binder(2026) Stålhammar, OlofCordwood masonry is a vernacular building technique that utilizes short pieces of wood in a binder matrix. The binder matrix used today is usually cement, lime-mortar or clay all with various downsides including thermal bridging, high environmental impact or difficulties of separating the materials at end of life. A novel binder made of a mixture of starch-based glue, lignin and saw dust is investigated to determine if the mechanical properties make it suitable to serve as an alternative. Samples of the binder are tested experimentally to find how it reacts to an outdoor environment and compressive strength. The parameters are used to develop a model of a wall element for FE-analysis that is compared with calculations based on Eurocode to verify the suitability of the material. This thesis found the best binder candidate to be one with two parts lignin and one part saw dust. This binder has a compressive strength of 0.4 N/mm2 and a modulus of elasticity of 13.7 N/mm2. This is sufficient for walls in a one-story building according to both the Eurocode calculations and the FE-model. This binder candidate withstood the weather during the three-month trial with only little damage while other candidates partially dissolved after 30-40 days in an exposed environment. The binder performed even better in a semi-sheltered environment, with little to no visible damage.
- Torsional Wind Response in Asymmetrical Timber Buildings - A Parametric Study of Plan Irregularity in Mid-Rise Structures(2026) Dahlgren, RebeckaWind loading often governs the lateral response of mid-rise timber buildings and can be critical for torsion, since the structure may rotate in addition to swaying. This thesis applies a parametric modal study of rectangular and L-shaped timber floor plans to identify when torsion governs the fundamental mode, and which stabilizer layouts most effectively reduce torsional sensitivity. The study is limited to the chosen investigated plan sizes and the structural configuration is based on a 6×6 m column grid with constant span lengths, rigid diaphragm action, and stabilizing systems modelled using CLT shear walls and (where applicable) a core, whose lengths, and positions are varied parametrically. Effects such as openings/discontinuities, height/vertical irregularities, connection flexibility, additional bracing systems, and explicit wind-response/comfort checks are outside the scope. Across both geometries, torsion is governed by the combined effect of (i) eccentricity, e, between the center of mass (CM) and the center of rigidity/rotation (CR), expressed as the normalized measure e/D, where D is the plan diagonal, and (ii) the torsional resistance provided by stabilizer lever arms, represented by the normalized torsional stiffness R =qKθ/(Kx + Ky). Here, Kθ is the torsional stiffness about CR, while (Kx and (Ky are the total lateral bending stiffnesses resisting sway in the global x- and y-directions. For rectangular plans, torsion becomes consistently likely once eccentricity is high. In the compiled results, configurations with a normalized eccentricity over the diagonal of the building plan (D), e/D ≥ 0.16 fall in the torsion-dominated region, while configurations with sufficiently high normalized torsional stiffness (R) (about R ≥ 13.5 m) remain translation-dominated. The most efficient torsion-reducing measures in the rectangular study were therefore avoiding stabilizer asymmetry that shifts CR (especially off-centre core placement) and increasing lever arms by placing stabilizers toward façades/corners. For L-shaped plans, torsion sensitivity is generally higher because geometric effects make low eccentricity harder to achieve in practice, so robustness relies more strongly on torsional resistance. In the combined L-shape summary, the key stiffness thresholds are Rcrit,1=10.0 m and Rcrit,2=28.11 m, with corresponding boundary ratios (R/(e/D)) of roughly 128 and 184. Practically, configurations below the lower stiffness level are consistently torsion-prone, whereas for moderate eccentricities, maintaining R above the upper level is associated with translational behaviour. The most effective measures in the L-shape study were moving stabilizers toward the plan corners and avoiding pronounced directional stiffness imbalance, which was shown to broaden the range of torsion-dominated configurations. Overall, the analyses indicate that the most efficient design takes are (1) controlling eccentricity by limiting CR shifts (dominant for rectangles), and (2) maximizing stabilizer lever arms/torsional resistance (dominant for L-shapes). Configurations combining high eccentricity with low torsional resistance are the most torsion-sensitive and should be prioritized for detailed wind-serviceability verification.