| 1. | Orłowska-Gałęzia A. M., Graczykowski C., Pawłowski P. K., Ruta R., Rimasauskas M., Kuncius T., Majewska K., Mieloszyk M., Characterization of thermal expansion in additively manufactured continuous carbon fibre reinforced polymer composites using fibre Bragg grating sensors, MEASUREMENT, ISSN: 0263-2241, DOI: 10.1016/j.measurement.2024.114147, Vol.227, pp.114147-1-114147-15, 2024 Orłowska-Gałęzia A. M., Graczykowski C., Pawłowski P. K., Ruta R., Rimasauskas M., Kuncius T., Majewska K., Mieloszyk M., Characterization of thermal expansion in additively manufactured continuous carbon fibre reinforced polymer composites using fibre Bragg grating sensors, MEASUREMENT, ISSN: 0263-2241, DOI: 10.1016/j.measurement.2024.114147, Vol.227, pp.114147-1-114147-15, 2024Abstract:
This study investigates thermal strains in fibre reinforced polymeric samples manufactured using a modified Fused Deposition Modelling (FDM) method. The investigated material was a composition of polylactic acid (PLA) resin and continuous carbon fibres. Each test sample was equipped with two Bragg grating (FBG) sensors, one embedded inside and the other bonded to the surface. Both sensors monitored temperature-induced deformations
during the conditioning of the specimens in a thermal chamber. Multiscale, analytical and finite element method based models were implemented to quantify the temperature deformations. Research has revealed that in investigated samples, bending occurs due to thermal loading. This can result in an inaccurate estimation of the coefficient of thermal expansion when relying on surface deformation measurements. A proposed solution involves the use of one FBG sensor embedded inside the specimen or two FBG sensors placed symmetrically, capable of measuring axial thermal deformation and averaging the effects associated
with bending. Keywords:
Continuous Carbon Fibre Reinforced Polymer Composites, Fibre Bragg gratings, Thermal expansion , Additive manufacturing, Multiscale modelling |  |
| 2. | Pisarski D., Jankowski Ł., Decentralized modular semi-active controller for suppression of vibrations and energy harvesting, JOURNAL OF SOUND AND VIBRATION, ISSN: 0022-460X, DOI: 10.1016/j.jsv.2024.118339, Vol.577, pp.118339-1-118339-20, 2024Pisarski D., Jankowski Ł., Decentralized modular semi-active controller for suppression of vibrations and energy harvesting, JOURNAL OF SOUND AND VIBRATION, ISSN: 0022-460X, DOI: 10.1016/j.jsv.2024.118339, Vol.577, pp.118339-1-118339-20, 2024Abstract:
The study investigates the problem of decentralized semi-active control of free vibration. The control scheme is designed for implementation in a modular controller architecture, where a collection of subcontrollers is employed, with each subcontroller being associated with a subsystem that represents a component of the vibrating structure. Each subcontroller uses state feedback from adjacent subsystem sensors to perform vibration suppression and energy harvesting using a switching control law. Furthermore, the assumption is made that neighbouring subcontrollers exchange information collaboratively to estimate the effects of coupling forces, achieving control efficiency comparable to that of a centralized approach. The effectiveness of the proposed approach is demonstrated on a modular suspension platform equipped with semi-active dampers and electromagnetic energy harvesters. The approach is evaluated under various free vibration scenarios, encompassing faulty measurement conditions, and is compared to passive and heuristic state-feedback control strategies. The results confirm that the proposed method attains a superior control performance, independent of the degree of decentralization in the adopted controller architecture, rendering it a viable solution for addressing large-scale semi-active control problems. Keywords:
Vibration control,Energy harvesting,Adaptive control,Semi-active control,Decentralized controller |  |
| 3. | Tauzowski P., Błachowski B., Lógó J., Optimal topologies considering fatigue with reliability constraint, Advances in Engineering Software, ISSN: 0965-9978, DOI: 10.1016/j.advengsoft.2023.103590, Vol.189, pp.1-12, 2024Tauzowski P., Błachowski B., Lógó J., Optimal topologies considering fatigue with reliability constraint, Advances in Engineering Software, ISSN: 0965-9978, DOI: 10.1016/j.advengsoft.2023.103590, Vol.189, pp.1-12, 2024Abstract:
This paper addresses a challenging engineering problem that combines stress-limited topology optimization, reliability analysis, and plasticity-based low-cycle fatigue. Each of these issues represents a complex problem on its own, necessitating significant computational effort. In this study, we propose a novel approach that integrates safety assessment into the topology optimization process while considering the number of cycles for low-cycle fatigue. Our method employs a linear approximation of the performance function for safety control, incorporating the number of failure cycles within a complex, multi-level load program. The methodology is validated through real experiments, using a finite element model with cubic shape functions that yield nearly identical results between numerical and experimental outcomes in the case of fatigue-resistant design for a bi-axially tensioned structural joint. Keywords:
Topology optimization, stress constraints, Reliability analysis, low-cycle fatigue, fatigueplasticity | |
| 4. | Kowalczyk-Gajewska K., Maj M., Bieniek K., Majewski M., Opiela K.C., Zieliński T.G., Cubic elasticity of porous materials produced by additive manufacturing: experimental analyses, numerical and mean-field modelling, ARCHIVES OF CIVIL AND MECHANICAL ENGINEERING, ISSN: 1644-9665, DOI: 10.1007/s43452-023-00843-z, Vol.24, pp.34-1-34-22, 2024Kowalczyk-Gajewska K., Maj M., Bieniek K., Majewski M., Opiela K.C., Zieliński T.G., Cubic elasticity of porous materials produced by additive manufacturing: experimental analyses, numerical and mean-field modelling, ARCHIVES OF CIVIL AND MECHANICAL ENGINEERING, ISSN: 1644-9665, DOI: 10.1007/s43452-023-00843-z, Vol.24, pp.34-1-34-22, 2024Abstract:
Although the elastic properties of porous materials depend mainly on the volume fraction of pores, the details of pore distribution within the material representative volume are also important and may be the subject of optimisation. To study their effect, experimental analyses were performed on samples made of a polymer material with a predefined distribution of spherical voids, but with various porosities due to different pore sizes. Three types of pore distribution with cubic symmetry were considered and the results of experimental analyses were confronted with mean-field estimates and numerical calculations. The mean-field ‘cluster’ model is used in which the mutual interactions between each of the two pores in the predefined volume are considered. As a result, the geometry of pore distribution is reflected in the anisotropic effective properties. The samples were produced using a 3D printing technique and tested in the regime of small strain to assess the elastic stiffness. The digital image correlation method was used to measure material response under compression. As a reference, the solid samples were also 3D printed and tested to evaluate the polymer matrix stiffness. The anisotropy of the elastic response of porous samples related to the arrangement of voids was assessed. Young’s moduli measured for the additively manufactured samples complied satisfactorily with modelling predictions for low and moderate pore sizes, while only qualitatively for larger porosities. Thus, the low-cost additive manufacturing techniques may be considered rather as preliminary tools to prototype porous materials and test mean-field approaches, while for the quantitative and detailed model validation, more accurate additive printing techniques should be considered. Research paves the way for using these computationally efficient models in optimising the microstructure of heterogeneous materials and composites. Keywords:
Pore configuration, Anisotropy, Elasticity, Micro-mechanics, Additive manufacturing | |
