Article
Polymer Science
Abdelrasoul Gadelmoula, Saleh Ahmed Aldahash
Summary: The study investigates the tribological properties of glass bead-filled PA12 composite materials manufactured by the SLS process. The orientation of build layers relative to the sliding plane is found to determine the dominant wear pattern and wear rate.
Article
Chemistry, Physical
Russell A. Rowe, Ali Tajyar, Michael Munther, Kurt E. Johanns, Paul G. Allison, Kasra Momeni, Keivan Davami
Summary: Research on surface mechanical properties and deformation behavior of nickel-based superalloys, such as Inconel 625, using nanoindentation technique revealed that the initial pop-in load during serrated plastic flow increases with temperature due to the formation of strengthening precipitates. The size of serrations and dislocation nucleation also show a trend with changing temperature.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Polymer Science
Michael J. Imburgia, Jessica L. Faust, Johan Ospina Buitrago, Rachael E. Enfield, Joseph D. Roy-Mayhew
Summary: This study investigates the effects of UV and water-spray exposure on the mechanical properties of an additively manufactured polyamide 6 blend. The study found that exposed samples maintained their strength while the impact strength increased. Additionally, the use of coatings preserved mechanical properties and improved the appearance.
Article
Materials Science, Ceramics
Bo Yang, Jaehun Cho, Xin Li Phuah, Haiyan Wang, Xinghang Zhang
Summary: This study successfully fabricated a complex gear-shaped part with high density and wear resistance using additive manufacturing and flash sintering techniques. The research demonstrates the efficiency of flash sintering technique in producing complex-shaped parts.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2021)
Article
Engineering, Mechanical
A. Panerai, A. Canegrati, L. M. Martulli, M. Kostovic, G. Rollo, A. Sorrentino, M. Carboni, A. Bernasconi
Summary: Additive manufacturing of Short Fibre Reinforced Polymers (SFRPs) combines good mechanical properties with high design flexibility. Fatigue tests were performed on SFRP specimens with different raster orientations. The results showed thermal and mechanical fatigue regimes. The fatigue behavior of this material was found to be dominated by the polyamide matrix.
INTERNATIONAL JOURNAL OF FATIGUE
(2023)
Article
Materials Science, Multidisciplinary
R. Roszak, D. Schob, I Sagradov, K. Kotecki, H. Sparr, Ph Maasch, R. Franke, M. Ziegenhorn
Summary: The study analyzed the temperature dependent material and damage behavior of additively manufactured polyamide 12, concluding that the Chaboche material model and Gurson-Tvergaard-Needleman damage model are suitable for simulating material and damage behavior.
MECHANICS OF MATERIALS
(2021)
Article
Materials Science, Characterization & Testing
Todd C. Henry, Terrence E. Johnson, Robert A. Haynes, Albert Tran
Summary: Additive manufacturing technologies can produce structures with complex geometry, but they are sensitive to stress concentrations which can reduce overall strength and fatigue performance. The study presented a topology optimization process for designing a beam subjected to loading, successfully reducing material volume and mass while decreasing stress concentrations. Experimental results showed that vertical members typically failed due to buckling and material yielding under fatigue loading.
JOURNAL OF TESTING AND EVALUATION
(2021)
Article
Engineering, Aerospace
Sebastian-Marian Zaharia, Mihai Alin Pop, George Razvan Buican, Lucia-Antoneta Chicos, Valentin Marian Stamate, Ionut Stelian Pascariu, Camil Lancea
Summary: Metallic additive manufacturing technology is increasingly being used by aviation companies to manufacture prototypes or components with complex geometric shapes, which are then tested and put into operation. This paper presents the design, fabrication, and testing of the mechanical performance of A6 steel specimens made through a selective laser sintering process, with maximum three-point bending strength of 983.6 MPa and maximum tensile strength of 398.6 MPa.
Article
Engineering, Mechanical
Dan Ioan Stoia, Liviu Marsavina, Emanoil Linul
Summary: The paper presents experimental investigations on fracture properties of polyamide PA2200 samples obtained by selective laser sintering. The results show that defects significantly affect the material properties, and introducing different percentages of defects can directly impact the material's absorbed energy. When determining fracture properties, the presence of geometrical defects needs to be considered.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2021)
Article
Engineering, Mechanical
Andrea Avanzini, Davide Battini, Stefano Pandini
Summary: Static, fatigue and notch sensitivity tests were performed on MJF-PA12 specimens, and fracture surfaces were comparatively analyzed. The results showed that MJF-PA12 exhibited static and fatigue properties comparable to conventional PA12. The sharp notch reduced static strength and fatigue life, while the blunt notch had limited impact on fatigue strength.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Materials Science, Ceramics
Sarah Boardman, Corinne E. E. Packard
Summary: Lithography-based ceramic manufacturing (LCM) faces challenges in achieving full density due to the use of slurries with low solids loading. In addition, the current literature lacks consensus on heat treatments for reaching full densities. This study investigated the influence of varying debinding and sintering parameters on the density, microstructure, and flexural strength of LCM-formed alumina. The results showed that removing bisque-fire and fine-tuning sintering parameters can produce LCM alumina parts with full densities and high flexural strengths comparable to traditionally processed alumina.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2023)
Article
Engineering, Aerospace
Yasutaka Satou, Hiroshi Furuya, Shoko Kaida, Tomoyuki Miyashita
Summary: This paper addresses the accurate prediction of the releasing and deploying behaviors of a creased space membrane. Experimental and finite element analysis results indicate that the opening angle of the crease increases with elapsed time after release due to stress relaxation. An analytical model is proposed to predict the releasing behavior, which shows good agreement with experimental results. Viscosity is considered important in predicting the releasing behavior of the space membrane.
Article
Engineering, Manufacturing
Jia-Ning Zhu, Zhaoying Ding, Evgenii Borisov, Xiyu Yao, Johannes C. Brouwer, Anatoly Popovich, Marcel Hermans, Vera Popovich
Summary: Through spark plasma sintering (SPS) method, directional cracks in [001] textured L-PBF NiTi shape memory alloy were successfully repaired, resulting in improved mechanical properties and superelasticity, addressing the limitations of hot cracking.
VIRTUAL AND PHYSICAL PROTOTYPING
(2023)
Article
Polymer Science
Luoyu Roy Xu, Qinglin Wang, Yinxu Ni, Gonghe Zhang, Fenghua Liu, Xiaodong Zheng, Yang Liu
Summary: As the use of additively manufactured materials in load-bearing structures increases, strength research becomes crucial. However, there is limited research on the shear strength measurements of additively manufactured polymers. This study proposes a new approach that combines experimental and numerical investigation to measure interlayer shear strength, focusing on FDM and SLS-made polyamide (PA12) specimens.
Article
Automation & Control Systems
Maximilian Kroenert, Thomas Josef Schuster, Felix Zimmer, Jens Holtmannspoetter
Summary: This study investigated the effect of specimen build orientation on the mechanical properties of selective laser-sintered polyamide 12. The results showed that the build orientation has no significant influence on the long-term creep behavior at high stresses, but it does affect the viscoelastic strain at low stresses.
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
(2022)
Article
Instruments & Instrumentation
Saeid Hedayatrasa, Mathias Kersemans
Summary: The intra-cellular wave dynamics of a water jetted phononic plate were experimentally investigated using high-resolution three-dimensional scanning laser Doppler vibrometry. The study focused on the vibrational behavior around the ultra-wide bandgap of the plate and validated the attenuation and resonance of both symmetric and antisymmetric wave modes. The results demonstrated the effective excitation of symmetric modes through mode conversion.
SMART MATERIALS AND STRUCTURES
(2022)
Article
Construction & Building Technology
Saeid Hedayatrasa, Gaetan Poelman, Joost Segers, Wim Van Paepegem, Mathias Kersemans
Summary: The study introduces the concept of phase inversion in thermographic inspection to decouple the AC component and filter second-order nonlinearities from the thermal response. The effectiveness of this phase inversion thermography (PIT) is theoretically substantiated and verified by finite element simulation. PIT robustly resolves the transient excitation and systematically decouples an AC response equivalent to the thermal response to an ideally linear and bipolar excitation.
STRUCTURAL CONTROL & HEALTH MONITORING
(2022)
Article
Engineering, Multidisciplinary
Vahid Yaghoubi, Liangliang Cheng, Wim Van Paepegem, Mathias Kersemans
Summary: Using vibration data and pattern recognition methods together is a common fault detection strategy for structures. This study proposes a deep learning framework, called CNN-DST, which combines convolutional neural networks and Dempster-Shafer theory to automate the feature extraction, selection, and classification processes. The proposed framework achieves a high prediction accuracy of 97.19% in classifying turbine blades with different types and severities of damage and shows robustness against measurement noise.
STRUCTURAL HEALTH MONITORING-AN INTERNATIONAL JOURNAL
(2022)
Article
Engineering, Multidisciplinary
Liangliang Cheng, Vahid Yaghoubi, Wim Van Paepegem, Mathias Kersemans
Summary: This paper proposes a novel Integrated Interval Mahalanobis Classification System (IIMCS) to accurately classify turbine blades based on vibrational response data with measurement uncertainty.
STRUCTURAL HEALTH MONITORING-AN INTERNATIONAL JOURNAL
(2023)
Article
Mechanics
Adil Han Orta, Mathias Kersemans, Koen Van Den Abeele
Summary: This study critically compares various commonly used models for calculating complex wavenumbers in viscoelastic orthotropic multi-layer materials. The accuracy and computational efficiency of these models are analyzed for material characterization. A comparative analysis is also performed on the through thickness displacement fields in the solid medium.
COMPOSITE STRUCTURES
(2022)
Article
Chemistry, Analytical
Adil Han Orta, Mathias Kersemans, Koen Van den Abeele
Summary: This study investigates the effect of using the in-plane and out-of-plane components of the recorded vibration velocity in the inverse determination of stiffness parameters in scanning laser Doppler vibrometry. The results show that accounting for the in-plane component leads to a more accurate and robust determination of the stiffness parameters.
Article
Engineering, Multidisciplinary
Gaetan Poelman, Saeid Hedayatrasa, Wim Van Paepegem, Mathias Kersemans
Summary: This paper introduces an improved infrared thermography method for detecting defects in woven fabric composites. The k-space filtering technique is applied to automatically decompose the thermographic image into a structured thermal background image related to the weave pattern, and a residual image representing other features (such as defects). The proposed method demonstrates enhanced performance in defect detection and sizing.
COMPOSITES PART B-ENGINEERING
(2023)
Article
Engineering, Multidisciplinary
Adil Han Orta, Jasper De Boer, Mathias Kersemans, Celine Vens, Koen Van Den Abeele
Summary: In this study, the elastic stiffness parameters of orthotropic plates are identified using a multilayer perceptron algorithm and guided wavefield data. A large training dataset is created using a semi-analytical finite element model, and the influence of training dataset size and signal-to-noise ratio on the inference outcome is examined. The performance of the multilayer perceptron-based method is validated on a numerical dataset and applied to experimental data from a multilayered glass-fiber reinforced polyamide 6 composite plate. The results of the multilayer perceptron-based method are compared with a traditional inversion algorithm, showing a difference of less than 0.5%.
Article
Engineering, Mechanical
Adil Han Orta, Mathias Kersemans, Nicolaas Bernardus Roozen, Koen Van Den Abeele
Summary: A two-stage inversion scheme is proposed to determine the complex-valued stiffness properties of orthotropic viscoelastic plates using their 3D surface velocity response. The hybrid TLS-ESPRIT and IWC method is used to extract the complex-valued wavenumber-frequency pairs corresponding to relevant Lamb wave and shear horizontal plate waves. Particle swarm optimization is employed to inversely determine the plate's orthotropic viscoelastic properties. Numerical simulations and experimental measurements validate the accuracy of the proposed method, showing a close agreement with the target values.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2023)
Article
Materials Science, Characterization & Testing
Xiaoyu Yang, Mathias Kersemans
Summary: This study investigates the use of pulse-echo ultrasound testing in different frequency ranges to characterize the in-plane fiber angle distribution and ply stacking sequence in a multi-layer composite laminate. Minimization of the Mumford-Shah functional is performed as an edge-preserving smoothing procedure for the recorded ultrasound dataset, followed by the application of a Gabor Filter-based Information Diagram approach to extract a 3D tomographic image of the fiber angles.
NDT & E INTERNATIONAL
(2023)
Article
Materials Science, Characterization & Testing
Zongfei Tong, Saeid Hedayatrasa, Liangliang Cheng, Cuixiang Pei, Zhenmao Chen, Shejuan Xie, Mathias Kersemans
Summary: This paper proposes a parametrized 3D finite element (FE) framework for simulating optical infrared thermographic inspection of multi-layer anisotropic media and generating a large-scale virtual dataset. The interface element is introduced for simulating various defect types, and non-uniform heating conditions and a stochastic morphology generator are used for realistic simulation. The trained Faster-RCNN model demonstrates excellent performance on experimental thermographic data.
NDT & E INTERNATIONAL
(2023)
Article
Polymer Science
Pei Hao, Siebe W. F. Spronk, Ruben D. B. Sevenois, Wim van Paepegem, Francisco A. Gilabert
Summary: The nonlinear behaviour of FRPC in transverse loading is mainly induced by the constituent polymer matrix, which is rate- and temperature-dependent. This paper presents a test setup to provide robust stress-strain measurements for FRPC at high strain rates. The micro- and macroscopic thermomechanical response of CF/PR520 and CF/PEEK systems are analyzed, showing excessive strain localization and discussing the differences between thermoplastic and thermoset matrices.
Article
Engineering, Mechanical
Saeid Hedayatrasa, Wim Van Paepegem, Mathias Kersemans
Summary: The technique of thermal wave radar or pulse compression thermography, which utilizes a broadband modulated excitation signal and its cross-correlation with the thermal response, is widely used in active infrared thermography for defect characterization. However, the distortion of the thermal response due to heat diffusion affects the efficiency of cross-correlation analysis, especially for deep defects or materials with different thermal diffusivity. To overcome this issue, diffusion-compensated correlation analysis (DCCA) thermal signal is proposed, using a frequency-modulated sweep signal as an excitation waveform. DCCA can accurately analyze the thermal response in the presence of measurement noise, and can directly map the corresponding depth or diffusivity based on a library of template thermal responses. The performance of DCCA is analytically substantiated and verified through simulations and experiments on carbon fiber reinforced polymer plates, showing its superiority over thermal wave radar. The technique has potential for thermographic inspection of materials with artificial defects.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2023)
Article
Engineering, Mechanical
Xiaoyu Yang, Mathias Kersemans
Summary: This paper proposes a C-scan imaging technique in the spectral ripple frequency domain, which improves the evaluation of complex and distributed defects in multilayer heterogeneous materials. The method processes the full A-scan signal without time gate, making it suitable for curved or tilted parts. It has been successfully demonstrated on carbon fiber reinforced polymer laminates with barely visible impact damage, showing its capability to resolve neighboring delaminations and small defects.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2023)
Article
Materials Science, Characterization & Testing
Zongfei Tong, Liangliang Cheng, Shejuan Xie, Mathias Kersemans
Summary: Infrared thermography (IRT) is a promising technique for defect detection in various materials. This study proposes an object detection algorithm based on Faster R-CNN for efficient extraction of defect features from IRT images. A virtual thermographic dataset for composite materials was constructed using a parameterized 3D finite element simulator. The deep learning framework trained on this dataset achieved high performance in the automated thermographic inspection of composite parts.
NDT & E INTERNATIONAL
(2023)
