Staff publications (CDS)

Permanent URI for this collectionhttps://dspace.lib.cranfield.ac.uk/handle/1826/13

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Access status: Open Access ,
Indonesia’s defense acquisition strategy
(Taylor and Francis, 2025-07) Matthews, Ron; Maharani, Curie; Jupriyanto; Wu, Shang Su
Indonesia is a huge archipelagic state, whose maritime security faces a growing strategic challenge from China. Jakarta's ability to respond, however, is hampered by its low share of military expenditure in national income. The resultant unaffordability means that military capability is dependent on loans from overseas’ contractors and banks to fund weapons acquisition. Consequently, Indonesia’s acquisition strategy has been focused on closing the gap between capability aspirations and budgetary reality. It represents a case study of unorthodox funding options, comprising export credits, countertrade and institutional loans. In turn, Indonesia’s acquisition pathways have been shaped by budgetary inadequacy, and include 2nd hand equipment markets, barter and international technology-sharing programs. Future acquisition policy reform is essential to remove the inefficiencies associated with the present cost-minimization approach.
Access status: Open Access ,
Supersonic projectile flow field reconstruction using background oriented schlieren and physics informed convolutional neural networks
(American Institute of Aeronautics and Astronautics (AIAA), 2025-07-25) Escudero, Miguel A.; Marinus, Benoît G.; Depuru-Mohan, Karthik; Debiasi, Marco; Saddington, Alistair J.
This work explores the use of axisymmetric background-oriented schlieren (BOS) imaging for reconstructing supersonic flow fields over a scaled NATO 5.56 mm M855 projectile at Mach 1.50, 2.00, and 2.50, as well as a 15° cone at Mach 2.50. A method for recovering density fields from BOS displacement maps was implemented, with results compared to a Taylor–Maccoll solution for the cone and a RANS CFD wind tunnel model for the projectile. Density field reconstructions showed errors below 15% overall and under 10% across most of the field, with the largest deviations near shock boundaries and stagnation regions. Additionally, force balance measurements were conducted on the projectile at Mach 2.50, showing an agreement of 1.2% with firing data from the literature and 8% with the RANS model. A custom U-Net was subsequently trained to predict pressure, temperature, and velocity fields from grid-transformed numerical density inputs over the cone, using a physics-exclusive loss function derived from the Euler conservation laws and specified boundary conditions. However, large residuals near the shock and stagnation point due to grid interpolation were found to impede the network’s performance. A purely data-driven model demonstrated good accuracy for pressure and temperature, a moderate performance for radial velocity, and poor accuracy for axial velocity. The model failed to generalize when fed with experimental data, reinforcing the need for strong physical constraints.
Access status: Open Access ,
Environmental impacts of low and high order detonations in water
(Elsevier, 2025-09-05) Sharma, Bhumika; Wardrop, Joshua; Persico, Federica; Webb, Sally; Coulon, Frederic; Temple, Tracey
The clearance of dumped munitions often relies on low order (LO) and high order (HO) detonation techniques, both of which pose significant risks to aquatic ecosystems. LO detonation leaves behind substantial explosive residues, whereas HO detonation generates intense shock waves and extensive fragmentation. This study examines the environmental impact of these detonation methods, including partial detonation, under semi-controlled conditions using six 1000-litre Intermediate Bulk Container (IBC) tanks. Partial detonation represents an incomplete LO detonation, resulting in the high transfer of TNT to the aquatic environment. Explosive residues were almost 8 times higher after LO detonations (8.7 ± 2.8 mg/L) compared to HO (1.2 ± 0.4 mg/L). Fragmentation analysis revealed that HO produced more than twice the number of fragments compared to LO, increasing the potential for physical damage. By integrating these findings with modelling, the fragment stopping distances were estimated. The maximum distance covered by the fragments ranged between 94.9 and 107.1 m. The acute toxicity spatial extent of explosive contamination from a single World War (WW) munition detonation was found to be 25–40 m (LO); 36–58 m (Partial); 14–23 m (HO). Considering, there are stockpiles of munitions in the water bodies, this distance can be much larger. These insights aid to minimise both chemical and physical environmental impacts, particularly in the context of World War-era munitions clearance.
Access status: Open Access ,
Preliminary assessment of quantitative phase analysis from focal construct tomography
(MDPI, 2025-06-01) Samuel, Varsha; Spence, Daniel; Farmer, Liam; Godber, Simon; Rogers, Keith; Dicken, Anthony
New methods for real-time materials phase identification based upon focal construct tomography (FCT) have been examined. Such quantitative assessment has significant potential in sectors where in-line analysis is required, including screening within aviation security. As a recent component of work programs developing FCT, its capability for accurate, quantitative analysis has been assessed for the first time. Diffraction signatures from mixed-phase materials were acquired from an energy-dispersive FCT system running under normal operational conditions. A calibration curve was constructed from the spectra and subsequently employed to assess the composition of ‘blind’ samples. The results demonstrated that this approach was able to precisely predict the polymorphic phase composition of samples to ±5 wt%. Conclusions: The potential impact of these findings is significant and will enable applications of FCT beyond those requiring a phase identification to those necessitating quantification, such as counterfeit medicines, pharmaceutical quality assurance, aging of explosives, and cement production.
Access status: Open Access ,
A novel Ku‐band waveguide piezo‐electric air gap capacitor using a single tuning element
(Institution of Engineering and Technology (IET), 2025-01) Loutridis, Abraham; Vagias, Ioannis; Leighton, Glenn J. T.; Shaw, Chris
In this work, a tuning element with controllable air gap integrated and implemented in a rectangular Ku‐band WR62 waveguide is presented. The proposed tuning element concept, consists of two, top and bottom, thin conductive parallelepiped arms, which are placed in the middle of the rectangular waveguide structure. The bottom arm is bending to control the gap width (w) between the two arms, whereas the second arm is fixed. The curvature of the bending arm is controlled by a piezo‐electric actuator, which affects the phase shift of the re‐scattered E‐field at the output port. The tuning element was designed with a 5% bandwidth centred at 15 GHz. The compact size, low‐cost and the easy‐to‐manufacture proposed design offers a considerable phase shift with very low insertion loss, given its electrical size and operational waveband. A prototype, for the distinct frequency band, has been manufactured and measured. The same prototype has been simulated in ANSYS HFSS. The numerical results will be later used to validate the actual electromechanical prototype.
Access status: Open Access ,
Phase processing techniques for the prediction of induced current
(IEEE, 2008-08) Wraight, Anthony; Morrow, Ivor L.; Robinson, John; Marino, Michael; Marson, Roger
This paper reviews the currently used minimum phase algorithm approach for the prediction of induced current as a result of the incidence of a time-domain electromagnetic environment such as an electromagnetic pulse. An alternative to this approach is proposed that enables the user to identify a lower bound on the minimum phase prediction. The technique has been applied to over 500 transfer functions with three different high-power electromagnetic environments and the results are presented and discussed within this paper. The paper concludes that the proposed method is a useful technique in providing an alternative method of predicting the induced current.
Access status: Open Access ,
Low level coupling techniques for the HIRF clearance of air systems
(IEEE, 2004-09-06) Wraight, Anthony; Hoad, Richard; Morrow, Ivor L.
Current methods for the assessment of military and civil systems for their response to High Intensity Radiated Fields (HIRF) are numerous and varied in their approach. The two principal methods employ either low level techniques for the calculation of transfer functions for extrapolation to high power environments or the use of high power sources specific to the environment to be considered. Low Level Swept (LLS) techniques are commonly used in the certification of both military and civil aircraft to HIRF. This paper examines the Low Level Swept Current (LLSC) technique and demonstrates the effect that the receive antenna height may have on the reference field calibrations. The results of this study show significant variation of up to 10dB which may be directly attributed to the electromagnetic test configuration. Moreover, recommendations are made to reduce measurement uncertainty.
Access status: Open Access ,
Physical Critical Infrastructure Protection - Security by Obscurity is No Defence for Western Survivability
(Cranfield University, 2025-04-10) Saunders, Ian; Appleby-Thomas, Gareth J.
Critical Infrastructure - the systems, facilities and assets that are vital for the functioning and protection of society and the economy. The aim of this white paper is to undertake a broad analysis of the threats to Critical Infrastructure and how western democracies address them, alongside highlighting the enormity and the complexity of the issue, hopefully prompting new dialogue and, more importantly, action. For the purpose of this paper, the authors have identified four vectors that define the threats relevant to critical infrastructure (Fig. 1). The increasing volume of academic research into the critical infrastructure ecosystem, as referred to later in this paper (Fig 10.) is a tangible indicator of its importance, particularly the patterns emerging from Chinese institutions. The question of whether this evolving research is from a futureproofing/defence perspective or to greater understand the weakness of other nations is beyond the scope of this paper; it does however demonstrate a desire for increased knowledge and therefore capability. As a current example, the targeting of Ukrainian critical infrastructure by Russian forces demonstrates the importance of this arena, with such infrastructure now clearly Physical Critical Infrastructure Protection 3 identified as battlefield assets with game-changing strategic and psychological potential worthy of high levels of defence and a ‘building back better’ mindset. Drilling down into the threats affecting the critical infrastructure ecosystem, we observe that the challenges facing the two attack vectors are neither exclusively civil nor exclusively military but both, in the context of what has been termed ‘total war’. Indirectly, the same could be said of the two non-confrontational vectors. In the current geo-political climate, we are once again at a point where we must protect civilian assets from potential overt military, terrorist and covert aggression; our enemies are both seen and unseen. Due to the complex nature of the threats against critical infrastructure, the non-confrontational vectors, arguably both man-made and natural, require an almost identical style of response to those of the physical attack vector – namely enhanced physical resilience. Enhanced physical resilience is a passive form of defence and comes in the form of greater protection. As an example of the inherent importance of this approach, it is applicable even to elements of the seemingly less tangible ‘cyber’ domain. While the cyber-attack vector is proactively defending against attacks online and supported by a combination of public/private sector investment, tech development and constant deployment, the hardware, power and communications aspects of the cyber threat are at constant risk and require effective physical protection against converging threats. The authors have developed the Critical Infrastructure Threat Prism to highlight the protective synergy across the western powers at the strategic and operational levels. Only in the cyber-attack vector, however, is there any collective Critical 5 tactical level guidance or action in the form of the recent recommendation to include 12 essential security elements into all official and corporate Operational Technology (OT) procurement, as a minimum cyber security requirement. The Critical 5 nations have made no mitigation recommendations for the physical attack vector in relation to minimum physical resilience guidelines for critical infrastructure, nor the non-confrontational threat vectors relating to adverse weather and structural decay. This oversight could dramatically affect the defence capabilities of both the Five Eyes Alliance and NATO as well as the domestic operability of member states’- built infrastructure, critical or otherwise. The basic three-phase analysis of each critical infrastructure vector in this paper has also highlighted similar patterns of underreach in relation to the proactive hardening of physical critical infrastructure as a passive defence against attack and wider protection against adverse weather and structural decay.
Access status: Open Access ,
Calibration accuracy of RCS measurements in free space
(IEEE, 2025-06-20) Wickramasinghe, Pathiraja; Balleri, Alessio
When investigating Radar Cross Section (RCS) of targets, it is essential to establish confidence in the experimental calibration data. In this paper, experiments are presented which were carried out to determine the calibration accuracy achieved in performing free space target RCS measurements in the radar lab at Cranfield University. Calibration data were collected in the X-band (between 8.5 GHz and 12 GHz) using four off-the-shelf non-calibrated metallic spheres of different diameter: 30 mm, 38 mm, 80 mm and 100 mm. The results indicate an accuracy of less than ±2 dBm2 for the spheres measured on a styrofoam stand and with a Signal to Noise Ratio (SNR) of at least 40 dB for all spheres.
Access status: Open Access ,
Benign/Cancer diagnostics based on X-ray diffraction: comparison of data analytics approaches
(MDPI, 2025-05-14) Alekseev, Alexander; Shcherbakov, Viacheslav; Avdieiev, Oleksii; Denisov, Sergey A.; Kubytskyi, Viacheslav; Blinchevsky, Benjamin; Murokh, Sasha; Ajeer, Ashkan; Adams, Lois; Greenwood, Charlene; Rogers, Keith; Jones, Louise; Mourokh, Lev; Lazarev, Pavel
Background/Objectives: With the number of detected breast cancer cases growing every year, there is a need to augment histopathological analysis with fast preliminary screening. We examine the feasibility of using X-ray diffraction measurements for this purpose. Methods: In this work, we obtained more than 6000 diffraction patterns from 211 patients and examined both standard and custom-developed methods, including Fourier coefficient analysis, for their interpretation. Various preprocessing steps and machine learning classifiers were compared to determine the optimal combination. Results: We demonstrated that benign and cancerous clusters are well separated, with specificity and sensitivity exceeding 0.9. For wide-angle scattering, the two-dimensional Fourier method is superior, while for small angles, the conventional analysis based on azimuthal integration of the images provides similar metrics. Conclusions: X-ray diffraction of biopsy tissues, supported by machine learning approaches to data analytics, can be an essential tool for pathological services. The method is rapid and inexpensive, providing excellent metrics for benign/cancer classification.
Access status: Open Access ,
Quantification of smokeless powder (SLP) additives on hands after direct handling of bulk samples via a filter-and-shoot method
(Elsevier, 2025-07) Standley, Troy; Putruele, Carissa; Lambert, Gwladys; Kelly, Corin; Liechti, Jana M.; Redshaw, Zara; Stephaniuk, Nadia T.; Mai, Nathalie; Gallidabino, Matteo D.
Smokeless powders (SLPs) are easily available energetic materials that are often used in the construction of improvised explosive devices. Following a bombing incident, hand swabs are routinely collected from persons of interest (POIs) to assess potential SLP handling. However, the evidential significance of analytical findings remains difficult to assign due to the lack of systematic data on residue transfer. This study aimed to address this gap by determining the quantities transferred to hands (qT) of three common SLP additives – diphenylamine (DPA), dibutyl phthalate (DBP), and ethyl centralite (EC) – following direct handling of bulk samples, with the specific goal of enabling the estimation of expected qT ranges on a POI's hands under the hypothesis that they had handled SLP. A streamlined filter-and-shoot method was developed for residue collection and analysis, allowing direct chromatographic analysis without preconcentration steps. The results showed that qT values typically ranged from the high nanogram to low microgram level, with DBP exhibiting the highest values and EC the lowest, mirroring their relative concentrations in the SLP formulations. The total mass of SLP handled (MSLP) and the handler variability (HID) were identified as significant factors influencing qT, whereas the type of SLP (TSLP) had a much weaker effect. Notably, a strong linear dependence between qT and MSLP was observed for all the three compounds. Based on these findings, regression models were developed to estimate expected qT ranges (including means and standard deviations) at different MSLP values, providing a practical tool to refine interpretation where information on the amount of SLP handled is available. By establishing empirical data on SLP residue transfer, this study fills a critical knowledge gap in the literature, enhancing the ability to assess the significance of forensic findings and ultimately contributing to more robust interpretations in cases involving suspected SLP handling.
Access status: Open Access ,
Vitacrystallography: appearance and development of cancer-induced structural biomarkers in a mouse model
(MDPI, 2025-06-03) Avdieiev, Oleksii; Denisov, Sergey A.; Ajeer, Ashkan; Adams, Lois; Greenwood, Charlene; Nesbitt, Heather; Thomas, Keith; Rogers, Keith; Solovyeva, Olga; Mourokh, Lev; Lazarev, Pavel
Structural biomarkers determined by X-ray scattering of the tissues can complement conventional diagnostics and provide a pathway for early detection of diseases. In the present study, mouse models were utilized to observe the progression of prostate cancer. We induced cancer in the left lobe of the mouse prostate, whilst the right lobe was left uninoculated. The mice were sacrificed at increasing systematic time points, and lobe samples were subsequently analyzed using X-ray scattering. Control samples were also collected from healthy mice sacrificed at the same time points. This investigation revealed that the ratio between the X-ray scattering peaks associated with the lipids and water can serve as a structural biomarker of cancer, and this biomarker develops as the tumor advances. The obtained cancer trajectory can serve as a baseline for the determination of the disease stage, and the biomarker movement along the trajectory can be evidence of the healing or disease progression.
Access status: Open Access ,
A common physical and control interface for ISAM operations
(2025-06-04) Martin, Jack; Sahu, Sripad; Zaidi, Yaseen
The Common Physical and Control Interface (CPCI) is a standardised, open-source solution to enhance interoperability in In-Orbit Servicing, Assembly, and Manufacturing (ISAM) operations. The absence of a universal interface in current space systems increases integration complexity, costs, and inefficiencies. CPCI leverages IEEE 802.3 Power over Ethernet (PoE) to enable simultaneous power and data exchange, providing a scalable and modular plug-and-play solution for future space missions.
Access status: Open Access ,
Shock wave overpressure history mapping using high-resolution distributed acoustic sensing
(SPIE, 2025-05-25) Masoudi, Ali; Lee, Timothy; Beresna, Martynas; Critchley, Richard; Brambilla, Gilberto; Denny, Jack; Lopez-Amo Sainz, Manuel; Santos, José Luís; Sun, Tong
This study explored the use of high-resolution distributed acoustic sensing (HR-DAS) for measuring blast wave overpressures, addressing the limitations of conventional pressure transducers. Shock tube experiments were conducted to evaluate HR-DAS performance in capturing side-on blast overpressures, comparing its strain measurements with reference piezoelectric pressure transducers. The study examined the effects of sensing fibre orientation and mounting methods on sensor sensitivity. Results showed that HR-DAS strain histories aligned well with conventional pressure measurements. The findings demonstrate the feasibility of HR-DAS for blast wave sensing, highlighting its potential for further development and broader applications.
Access status: Open Access ,
ProSAir 2022.11 User Guide
(Cranfield University, 2022-11-01) Forth, Shaun
ProSAir (PROpagation Of Shocks in AIR) is a finite volume, compressible fluid dynamics solver based on second order MUSCL-Hancock time integration and the AUSMDV hybrid flux vector/difference splitting developed by Wada and Liou. ProSAir’s primary use is for modelling air-blasts in and around structures and estimating the resultant structural loading. ProSAir is a successor to Air3d version 9 and version 2022.11 still uses the same numerical algorithm. ProSAir improves on Air3d by an improved user interface. Key features are: Easy to use CFD modelling of blast waves caused by detonation of a single high explosive device. Fast and robust due to use of the well established AUSMDV finite volume scheme for accurately capturing shocks. Second order accuracy achieved by its MUSCL-Hancock integration scheme. Use of spherical and axi-symmetric calculation phases to reduce run times. Support for running on multi-core/processor computers. Windows XP/Vista/7/8/10 64-bit version supplied as standard; 32-bit version for use on legacy systems is still available. Graphical user interface allowing rapid building of geometric models made up of simple geometrical components. Graphical display of solution during execution. Batch jobs via command line invocation. Window failure model based on the SAFE/SSG Glazing hazard guide Can provide history of pressure, velocity, density and temperature at tens of thousands of target points around the domain. Graphical display may be captured to create video presentations. User guide with many examples including sample input and output files. Restrictions: Explosive charges are assumed ideal, spherical and with no afterburning. No method to input geometry from CAD packages. Flowfield itself cannot be post-processed.
Access status: Open Access ,
CFAR detection in heterogeneous K-distributed sea-clutter background
(IEEE, 2024-10-21) Mungara, Nagarakshith R.; Balleri, Alessio; Kocjancic, Leon; Acland, Tim
Detection of targets at sea is challenging due to unwanted echo returns from the sea surface, i.e. sea clutter returns. To account for the undesired effects due to sea clutter at the receiver, and to control the probability of detection and false alarm, the K-distribution has often been used to provide a promising statistical fit to real clutter data. However, controlling the performance of the receiver becomes very complicated in heterogeneous clutter, that is when there is a sudden transition from one clutter region to another with a change in shape and/or scale distribution parameters. A possible solution to this is to use some prior information on the sea clutter characteristics to generate clutter maps that inform adaptive detection solutions. This prior information can be obtained by the radar in real time (or close to real time) using oceanographic models, statistical clustering, or potentially Artificial Intelligence.This paper presents our first step in this direction by investigating detection in heterogeneous fully correlated K-distributed sea clutter. A transition line between homogeneous clutter regions is estimated using the statistical parameters of the K-distribution, to avoid polluting the training windows of a Constant False Alarm Rate (CFAR) detector with non-representative data. The transition cells assist to resolve the heterogeneous clutter into small homogeneous clutter regions and for every homogeneous region a CFAR detector is designed according to the K-distribution shape parameter. Results are obtained and presented for simulated data as well as for real sea clutter data provided by Hensoldt UK.
Access status: Open Access ,
Of rodents and foxes: faunal activity and scavenging at carcasses in a Central European (Swiss) forest
(Wiley, 2025-12-31) Indra, Lara; Moser, Valentin; Milella, Marco; Errickson, David; Lösch, Sandra
Vertebrate activity can significantly affect forensic investigations. Trauma interpretation is impaired when vertebrates scavenge on injuries and inflict damage, and scavengers can hinder the recovery of human remains through dispersal. However, forensic scavenging research is scarce in Europe and lacking for Switzerland. We conducted a 2‐month baseline study followed by a 5‐month experiment with six domestic pig (Sus scrofa domesticus) carcasses in a Swiss forest during summer through fall. We monitored each three caged and uncaged carcasses with camera traps and documented vertebrate activities and taphonomic signatures on the remains and calculated the scavenging rate. Rodents (Apodemus sylvaticus, A. flavicollis, and Myodes glareolus) and red fox (Vulpes vulpes) scavenged and dispersed the remains. All carcasses and ca. 4% of the recovered bones exhibited scavenging marks, including wet bone scavenging (rodents) mainly on small bones and protruding features, and scoring (red fox) on a rib. The presence of a carcass, decomposition stage, sun exposure, and use of cages significantly influenced the number of vertebrate visits at the plots. Rodents preferentially scavenged caged, skeletonized remains at tree‐covered plots and modified perimortem wounds beyond recognition. The few carnivore sightings focused on uncaged specimens. The generally low scavenger participation was likely season‐related, due to the rapid maggot infestation, or human presence. Future studies should evaluate the influence of these variables, including sun exposure. Our study informs forensic casework by highlighting the importance of rodents and to a lesser degree foxes as vertebrate scavengers and dispersal agents in central European temperate forests.
Access status: Open Access ,
Age estimation using CT images of the pubic symphysis of Lebanese living individuals
(Elsevier, 2025-07-01) Mansour, Cindy; Márquez-Grant, Nicholas; Lescure, Javier; Eid, Sarah; García Velasco, María; Benito Sánchez, María
While the Suchey-Brooks method for age estimation is generally accepted in forensic anthropology, its accuracy varies among different populations. This retrospective cross-sectional study aims to test the reliability of the Suchey-Brooks method using Computed Tomography (CT) scans of pubic symphyses of 155 Lebanese living individuals (76 males and 79 females) aged 17 to 98 years. This study reveals that 94.9 % of the sampled individuals fell within the range of 2 standard deviations from the reference mean for predicted age. Additionally, the study assesses phase assignation, overall bias of 1.29, and overall inaccuracy of 8.09, along with strong intra and inter-observer reliability with weighted Cohen’s Kappa (k) 0.901 and 0.82, respectively. Transition analysis was also used to generate new Lebanese age references. The new reference proposed in this study improves the accuracy of age-at-death estimation compared to the Suchey-Brooks method when applied to the Lebanese population.
Access status: Open Access ,
Factorial analysis of the influence of both water and oxygen on extruded double base rocket propellant decomposition
(Wiley, 2025) Jabalquinto, Alonso Romero; Mai, Nathalie; Heil, Moritz; Castedo, Guillermo Frades; Gill, Philip P.
The decomposition mechanisms of double base rocket propellants are well known and reported, but the influence of atmospheric conditions such as water and oxygen is poorly understood. In this work, the influence of water and oxygen on an extruded double base (EDB) rocket propellant aged between 70 and 100°C was examined using heat flow calorimetry. The results show that increased water content and higher oxygen concentration both lead to elevated heat flow. The activation energy (Ea), which was determined using the Friedman differential isoconversional method, showed that Ea decreases with higher water content, suggesting water acts as a catalyst, while lower oxygen concentration increases Ea, indicating slower decomposition. Factorial design analysis confirmed that both factors negatively impact Ea, with oxygen being the more significant factor while the water/oxygen interaction (AB) on the Ea is negligible. This research provides critical insight into the factors affecting the stability and shelf life of rocket propellants, which can lead to improved formulations and storage conditions, augmenting the safety and performance of EDB rocket propulsion systems. This research provides critical insight into the factors affecting the stability and shelf life of rocket propellants, which can lead to improved formulations and storage conditions, augmenting the safety and performance of EDB rocket propulsion systems.
Access status: Open Access ,
Stress analysis of gun breech block for gun design applications
(DEStech Publications Inc., 2025-05-19) Abid, Rabia; Appleby-Thomas, Gareth J.; Goyder, Hugh; Grasso, Marzio; Hameed, Amer; Carlucci, Don; Uhlig, W. Casey
This study presents a detailed Finite Element Analysis (FEA) of a breech block featuring a buttress thread, aimed at understanding the stress distribution under various loading conditions. Buttress threads, known for their high load-bearing capacity and asymmetrical profile, are commonly used in applications where high axial loads are required, such as in hydraulic systems and fasteners. Utilizing Abaqus, a comprehensive stress analysis was conducted on the threaded block to assess critical factors such as stress concentration, deformation patterns, and the overall integrity of the design under different loading scenarios. The model was created using precise geometric definitions of the buttress thread, including the lead angle and asymmetric thread profiles. The material properties were assigned based on realistic parameters commonly used in industrial applications, this material was steel 4340. Static loading conditions were applied to simulate operational stresses, and a fine mesh was employed to capture the detailed stress distribution around the thread roots and flanks, where stress concentrations are typically highest. The results revealed that the buttress thread design effectively distributes axial loads along the inclined surface, minimizing stress concentrations compared to conventional thread forms. This design of the breech block based on the buttress thread is extremely important when it comes to the gun design and it is a good reason why the buttress thread is design in this way for most guns. However, significant stress concentration was observed at the root of the thread, necessitating potential design optimizations. This analysis demonstrates the efficacy of buttress threads for highload applications in gun designs, with the FEA results providing valuable insights for further refinement of the design. The study validates the use of Abaqus in performing detailed stress analysis of complex geometries, showcasing its capability to predict critical stress regions and potential failure points. Recommendations for future work include fatigue analysis and exploring the effects of varying thread dimensions on stress distribution to judge the novelty in our work.

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