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1

The influence of ball shot material on the surface properties of vibratory shot-peened parts

Skoczylas Agnieszka, Zaleski Kazimierz

Advances in Science and Technology. Research Journal

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2026

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Vol. 20, no. 2

515--528

EN

(VSP) process conducted with variable shot peening conditions. The variable parameters of the process were: ball material (100Cr6 and HS18-0-1) and vibratory shot peening time (t=1 min and t=15 min). Surface topography, surface roughness (3D parameters), surface microhardness, and residual stress were examined before and after the shot peening process. A multi-factor ANOVA analysis was performed for the surface roughness parameter Ra. For the C45 steel samples, the use of vibratory shot peening leads to increased surface roughness compared to that before shot peening. The 3D surface roughness parameters of 100Cr6 steel are lower after the vibratory shot peening process than before VSP. The effect of vibratory shot peening is increased microhardness, which is greater for the C45 grade of steel than for 100Cr6. After VSP, compressive residual stresses occur in the surface layer. The shot peening process conducted with the 100Cr6 shot produces surfaces with lower surface roughness than that obtained after shot peening with the HS18-0-1 shot, whatever the workpiece material and the time t. Regarding the physical properties of the surface layer (microhardness and residual stress), better results (a greater increase in the microhardness ΔHV and a higher absolute value of the compressive residual stress σ) were produced by the shot peening process conducted with HS18-0-1 balls.

2

Residual stresses in steel I‑sections after cold forming about strong axis

Marcinczak Krzysztof

Materiały Budowlane

|

2025

|

nr 5

32--39

EN

This article presents the issue of self stresses and the methods for determining them. Describes the methodology of using the hole drilling method to determine the residual stresses occurring in cold bended I beams to the strong axis. The results of a study of the residual stresses in a steel I beam made of S460M steel are presented. The resulting stress distributions are compared with theoretical models.

PL

W artykule omówiono zagadnienie naprężeń własnych oraz metody ich określania. Opisano metodę wykorzystania metody otworkowej do określenia naprężeń własnych występujących w dwuteownikach giętych na zimno względem silnej osi bezwładności. Przedstawiono wyniki badań naprężeń własnych w stalowej belce dwuteowej ze stali S460M. Otrzymane rozkłady naprężeń porównano z modelami teoretycznymi.

3

Modeling the point cold forming process of arch girders

Marcinczak Krzysztof

Materiały Budowlane

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2025

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nr 11

23--29

EN

This article discusses the issue of point cold bending of hot-rolled I-sections about weak axis. The residual stresses after the cold bending process were determined using numerical analyses. The results were obtained from a calibrated model based on experimental tests.

PL

W artykule omówiono zagadnienie dotyczące punktowego gięcia na zimno dwuteowych kształtowników gorącowalcowanych względem słabej osi bezwładności. Za pomocą analiz numerycznych wyznaczono naprężenia pozostałe po procesie gięcia na zimno. Wyniki uzyskano na podstawie skalibrowanego modelu otrzymanego z badań doświadczalnych.

4

Investigation of a vibratory stress relief system for hard-turned EN 31 components

Bhokare Pankaj, Vasistha Vishal

Engineering Transactions

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2025

|

Vol. 73, iss. 2

177--197

EN

This study examines the use of artificial neural networks (ANNs) to forecast and optimize residual stress and Brinell hardness in EN 31 components subjected to vibratory stress relief (VSR). The influence of important process parameters – amplitude, frequency, and time – was determined through comprehensive ANOVA analyses. According to the findings, residual stress and Brinell hardness are substantially influenced by amplitude, while frequency plays a crucial role in managing stress and hardness before VSR. The significance of time varied across different processes. The ANN model consistently demonstrated high predictive accuracy, achieving 99.82% for Brinell hardness after VSR, 98.27% for residual stress after VSR, 99.98% for Brinell hardness before VSR, and 98.20% for residual stress before VSR. Model performance was further improved through data transformation and normalization. A robust framework for optimizing VSR process parameters was established by integrating ANOVA and ANN, which enabled precise control over mechanical properties. This research emphasizes the potential of ANN in predictive modeling and process optimization in materials engineering, providing valuable insights for enhancing the performance and reliability of mechanical components through customized VSR processes.

5

Statistical evaluation of the measurement of residual stresses in the surface layer of CP1000 steel sheets using the magnetic Barkhausen noise and X-ray methods

Kliś Janusz, Nawrat Rafał, Olbrych Jakub, Węgrzyniak Michał, Szydło Damian, Toczek Grzegorz, Sozańska-Jędrasik Liwia

Computer Methods in Materials Science

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2025

|

Vol. 25, No. 1

15--30

EN

The paper presents an analysis of the possibility of measuring the residual stresses of metal sheets with the application of the so-called Barkhausen effect. The aim of the research was to compare the residual stress levels measured by two methods of multiphase steel sheets (ferritic-martensitic-bainitic) in grade HCT980C after flattening on a roller leveller in industrial conditions. The measurements were carried out using two methods: the Barkhausen effect method and the X-ray method. The paper describes in detail the methodology used for testing the measurement of residual stresses. The residual stress testing of sheets made of the CP1000 steel group was supplemented with tests of chemical composition, microstructure and mechanical properties (Re, Rm, A80, HRC hardness). In the analysis of the research results, elements of statistics were also used, in the form of ordinary correlation. The research results showed that in the case of sheets after flattening on a roller leveller in industrial conditions, it is possible to replace the commonly used and recognized, but labour-intensive X-ray method, with a simple, innovative and cheap to use method using the Barkhausen effect. Stress measurement using the Barkhausen effect has already been found to be applicable in the diagnostics of tracking changes in the stress value in the material in industrial pipelines, where access to the other measurement methods is difficult or even impossible. Currently, the measurement of stress in sheets by the magnetic method is introduced on the transverse cutting line when cutting the sheet metal from coils to metal sheets. The measurement of stresses in the production of steel sheets is important because the difference in stress between the top and bottom sides of the sheet has a significant effect on the flatness of manufactured metal sheets.

6

Influence of rivet material and squeeze force on the riveting process and residual stresses in riveted joints used in aircraft structures

Korbel Adam, Manitcaia Valeria, Machniewicz Tomasz

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2025

|

Vol. 73, nr 5

art. no. e154721

EN

The paper presents the results of experimental research and finite element analyses (FEA) on the impact of the aircraft rivet installation process and the type of rivet material on the geometric parameters of the driven rivet head, rivet hole expansion (relative interference), residual stresses in sheets, clamping stress and clamping force between sheets in three-row riveted lap joints, as well as linking the obtained results with observations of fatigue crack initiation sites in real riveted joints. The research was conducted for universal head rivets (MS20470AD5-5 and MS20615-5M5) with a shank diameter of 3.96 mm and a length of 7.94 mm, made of two materials, namely aluminium alloy (2117-T4) and nickel-copper alloy (Monel 400), used to join two AA2024-T3 sheets with a thickness of 1.0 mm and 1.6 mm. The experimental tests focused on determining the mechanical properties of sheet and rivet materials (using the digital image correlation DIC technique), geometric parameters of driven rivet heads, and rivet hole expansion, depending on the rivet material and the riveting force level. The results obtained from the numerical models revealed that at the same degree of rivet squeezing, rivets made of Monel 400 generate significantly higher negative residual stresses and residual clamping than rivets made of AA2117-T4, which will affect the contribution of friction to load transfer by a given rivet row and the fretting phenomenon in real riveted joints. The region of compressive residual hoop stress in sheets and the clamping force influence the fatigue crack initiation site and the crack path.

7

Analyzing the use of rigid- or elastic-plastic finite models for the simulating of cutting processes

Stupnytskyy Vadym, Prodanchuk Oleh, Dyshev Oleksand

Archive of Mechanical Engineering

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2025

|

LXXII, nr 1

131--152

EN

The simulation modeling of cutting processes represents a powerful scientific instrument for investigating stress-strain and thermodynamic processes in machined materials. Nevertheless, the principal obstacle to the extensive deployment of this scientific approach is inadequate precision of the resulting research outcomes. This is due to the complexity of formalizing the physical and mechanical forming pattern, considering all the dominant factors in building a high-quality cutting model. Additionally, there is a need for professional experience from the researcher to correctly describe the physical model of the material, as well as a logical selection of fracture criteria, among other factors. One of the most significant challenges in ensuring the accuracy of cutting modeling processes is formalization of the description of a rigidplastic or elasto-plastic FEA model for analyzing the behavior of materials during machining. The article presents a scientifically based argument for the practicality of using these techniques in simulation modeling systems. It also provides practical recommendations for researchers on constructing an accurate FEA simulation model in DEFORM 2D. The conclusions drawn from the analysis of simulation studies of cutting-induced residual stresses for heterogeneous materials are confirmed by experimental investigations.

8

Assessment of induced residual stresses and microstructure of Al/B4C/FA composite extruded by equal channel angular pressing

Irhayyim Tiba Qahtan, Gattmah Jabbar Qassim

Advances in Science and Technology. Research Journal

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2025

|

Vol. 19, no. 7

338--345

EN

This research evaluates the residual stresses and microstructure of rods fabricated from a hybrid aluminum matrix composite (Al1050/B4C/FA). The rod composite is subjected to various passes (cycles) using equal channel angular pressing (ECAP) at room temperature. Channel angles of 120° and 135° with pass numbers of 1P, 2P, 3P, 4P, 5P, and 6P are used to investigate the in-duced residual stresses (IRS) and examine the microstructure. The destructive cutting technique (CT) is employed to assess the state of IRS in the axial direction, and scanning electron micros-copy (SEM) is used to check the microstructure before and after severe plastic deformation (SPD). The results show that the values of residual stresses tend to increase due to the effects of SPD compared to the casting composite. As the ECAP cycles increase, the magnitudes of residu-al stresses start to change; the compressive state of residual stresses is near the rod surface, while the stresses are in tensile state near the center of the composite rod. The cycles of ECAP signifi-cantly impact the grain size reduction. The smallest grain size is observed at a die angle of 120° after 6 ECAP passes, measuring between 1 and 8 µm, while the grain size for the casted rods ranged from 4 to 15 µm.

9

On the Application of Laser Shock Peening as a Manufacturing and Repair Process to Improve the Fatigue Performance of Refill Friction Stir Spot-Welded AA2024-T3 Joints

Kashaev Nikolai, Mohr Tim, Keller Sören, Suhuddin Uceu Fuad Hasan, Klusemann Benjamin, Dorn Falk, Ventzke Volker

Fatigue of Aircraft Structures

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2024

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Iss.16

29--44

EN

The refill friction stir spot welding (refill FSSW) process is an innovative solid-state spot-welding method, which has evolved from the concept of friction stir welding. Compared to riveting, the process has the advantage of avoiding stress concentration by eliminating holes. In addition, weight can be saved compared to riveting as no additional material is needed. However, the fatigue strength of refill FSSW joints under cyclic loading is still not satisfactory. To address this challenge, laser shock peening (LSP) is investigated as an innovative residual stress engineering technique to improve the fatigue performance of refill FSSW AA2024-T3 joints. Two application scenarios are investigated, one investigating the LSP technique as a complementary manufacturing process to the refill FSSW technology, and the other investigating the LSP technique as a repair process for damaged joints. The fatigue test results showed that the application of the LSP treatment can significantly improve the fatigue behaviour of the refill FSSW overlap joints. In terms of Basquin fatigue strength, the LSP treatment resulted in an improvement by a factor of 1.51 and 2.82 for the one- and two-sided LSP-treated specimens, respectively. The life of specimens with refill FSSW joints that had been specifically pre-damaged by stopping the fatigue test at approximately 51%, 75% and 83% of the number of cycles to the Basquin fatigue strength, applying LSP treatment and continuing the fatigue test was also significantly extended. The results of this study show that LSP is a very effective technique for significantly extending the fatigue life of refill FSSW joints. Therefore, the combination of these two manufacturing processes, refill FSSW and LSP, represents a promising technology for industrial companies that require high fatigue performance for their structural components.

10

FEM Analysis of Residual Stresses in Welded Aluminum and Polyamide 6

Praski Marcin, Kowalczyk Piotr, Szumowski Radosław, Stankiewicz Karolina, Leski Andrzej

Fatigue of Aircraft Structures

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2024

|

Iss.16

57--74

EN

Thermoplastic composites enable weldable, recyclable aircraft structures, but thermal mismatch between metals and polymers can introduce detrimental residual stresses. This study develops a finite element method (FEM) framework to predict residual stress fields in resistance-welded joints between aluminum 7075 and carbon-fiber-reinforced polyamide 6 (PA6). Transient thermal analyses with multilinear, temperature-dependent properties were coupled to mechanical analyses; contact conditions transitioned from frictional to bonded at PA6 melting. Three thermal cycles (20°C→220°C→20°C, 20°C→240°C→20°C, 20°C→260°C→20°C) were examined to assess peak-temperature effects. The simulations show stress contours that decay with distance from the bond and reveal pronounced peaks in both normal and shear components at weld edges, consistent with shear-lag theory. Within the bonded interior, average stresses are relatively low, whereas edge concentrations identify likely sites for debonding or delamination initiation. The magnitude of residual stresses increases with thermal gradient, underscoring the need for parameter control during welding. The FEM outputs will be validated against uniaxial tension and three-point bending tests on welded specimens, with future work quantifying fatigue-life reduction under combined thermal and mechanical cycling. The results highlight mitigation priorities for bonded repairs and hybrid aerospace structures, including process-curve tuning (current/pressure/cooling) and edge-region design measures.

11

Modeling the thermo-mechanical response and phase changes in metallic additive manufacturing (MAM) processes using a dissipative phase-field model

Darabi Roya, Azinpour Erfan, Reis Ana, Sa de Jose Cesar

Computer Methods in Materials Science

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2024

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Vol. 24, No. 2

5--25

EN

Additive manufacturing (AM) has emerged as a highly promising manufacturing technique, offering unprecedented possibilities for creating complex geometries and functional structures. However, harnessing the full potential of AM requires the development of a robust computational framework capable of capturing the intricate multi-scale and multi-physics nature of the process. The constitutive and structural responses encountered in AM are particularly challenging to reproduce due to the complex behavior of the material involved. This research aims to address these challenges by presenting a comprehensive computational approach that incorporates a material model capable of accurately representing the behavior of different phases occurring during AM. To achieve this, the finite element method, using the Lagrangian framework in the implicit time scheme, is employed through the widely adopted ABAQUS software. Computational implementation is facilitated using the FORTRAN programming language. By employing weakly coupled thermal and mechanical constitutive equations, the framework enables the analysis of thermal stresses, strains, and displacements during realistic solidification processes, which inherently involve highly nonlinear constitutive relations. Through a series of numerical examples, the capabilities of the proposed model are demonstrated across various computational scales, particularly during the rapid melting and solidification phases. These simulations reveal the formation of residual stresses, which can lead to part distortion and have detrimental effects on the mechanical properties of the manufactured components. This research contributes to the advancement of additive manufacturing by providing a reliable computational tool that integrates the complex interplay between thermal and mechanical phenomena. The developed framework enhances our understanding of the AM process, offering valuable insights into the factors influencing the structural integrity and performance of additively manufactured parts.

12

Phase transformation effect on residual stress development in fusion welding of dissimilar stainless steels with different thickness

Dwibedi Swagat, Kumar Bikash, Bag Swarup

Archives of Civil and Mechanical Engineering

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2024

|

Vol. 24, no. 3

art. no. e148, 2024

EN

The residual stress creates deleterious effects on joint properties of dissimilar welding due to differential thermophysical properties and mechanical constraints of dissimilar thickness. Accounting of solid-state phase transformation (SSPT) through the understanding of solidification behavior enhances the prediction accuracy of residual stress. The characterization of microstructural features improves the fundamental understanding of the residual stress evaluation. An attempt is made to comprehend the dependence of heat input on phase transformation and its effect on the generation of compressive residual stress in dissimilar welding. Three distinct heat inputs of 52, 63, and 77 J/mm are considered in micro-plasma arc welding (µ-PAW) of SS316L and SS310 with thicknesses of 800 µm and 600 µm, respectively. The measurement of residual stress is performed using the X-ray diffraction (XRD) method. The variation of δferrite from 11.2 to 7.9% is analogous to the variation of average δferrite lath size from 412 to 1040 nm, where inter-dendritic spacing varies from ~ 10 µm to ~ 20 µm. The solidification mode is identified as ferritic-austenitic (FA), which results in the formation of skeletal and lathy δferrite structures. Electron Backscatter Diffraction (EBSD) results show an increase in heat input leads to an increase in low-angle grain boundaries that results in a rise in the residual stress value. The phase fraction and residual stresses are computed employing a finite element (FE) based thermal-metallurgical-mechanical (TMM) model including the effect of SSPT. The reasonable agreement between the computed and experimental measurements with a maximum error of ~ 8.5% in weld size, ~ 7.5% in peak temperature, ~ 16% in retained δferrite, ~ 17% in residual stress, and ~ 5% in distortion demonstrates the reliability of the developed model. A lower level of heat input (52 J/mm) allows the formation of a high amount of δferrite, which generates comparatively more compressive stress as a disparity in thermal expansion coefficient aids in the reduction of residual stress.

13

Microstructure, residual stress and mechanical properties of double carbides cermet coatings manufactured on AZ31 substrate by high velocity oxy‑fuel spraying

Jonda Ewa, Łatka Leszek, Godzierz Marcin, Olszowska Karolina, Tomiczek Anna

Archives of Civil and Mechanical Engineering

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2024

|

Vol. 24, no. 2

art. no. e61, 2024

EN

The study investigated the microstructures, residual stress and mechanical properties of double carbides cermet coatings manufactured on AZ31 magnesium alloy substrate by high-velocity oxy-fuel spraying (HVOF). The HVOF spraying was carried out using a JP 5000 TAFA spray system and the commercially available powder WC-20Cr3C2-7Ni was used to manufacture coatings. The variable process parameter was spray distance (320, 360 and 400 mm). The top surfaces of the manufactured coatings are typical for HVOF coatings and is relatively smooth. Nevertheless, some irregularities and voids are observed. All coatings exhibit dense structure with relatively low porosity level (below 3 vol. %) as well as a robust mechanical binding to the substrate which indicates high adhesion. More deep microstructure analysis carried out by TEM microscopy revealed two types of precipitation: WC hexagonal phase in the space group P-6m2 with irregular shape and size as well as Cr7C3 orthorhombic one, in the space group P nma with a rounded shape and regular size. Phase composition after the spraying process indicates the hexagonal WC phase as the main one. Additionally, two chromium carbides phases, Cr3C2 and Cr3C7 have been identified. A small peak of hexagonal W2C carbide was found as well. Analysis of residual stress showed that both components of linear stress for all deposited coatings have a compressive nature. The increasing spray distance caused an increase of the linear stress values, from – 72.7 up to – 131.5 MPa for δ11 and from – 57.2 up to – 112.2 MPa for δ22. Such values could suggest that thermal stress generated during coating deposition was also low. In the case of the shear stress the values are much lower than linear one, but with the same tendency, increasing with longer spray distance: 14.2, 21.0 and 32.2 MPa for 320, 360 and 400 mm, respectively. The obtained results of HIT show a slight influence on the spray distance. With the increasing spraying distance, the value of hardness decreasing: 12.96, 12.53 and 11.76 GPa according to SD equal to 320, 360 and 400 mm, respectively. Similar was in the case of the EIT values: 315, 309 and 304 GPa for 320, 360 and 400 mm, respectively. All values of the fracture toughness were in the range between 3.5 and 4.0 MPa m1/2, with little influece of the spray distance.

14

Influence of cryogenic-vibration compound field on the residual stress and forming accuracy during aluminum alloy forming

Li Cheng, Long Jinchuan, Wang Xinyun, Ning Bo, Li Desong, Feng Gang, Deng Lei, Tang Xuefeng

Archives of Civil and Mechanical Engineering

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2024

|

Vol. 24, no. 2

art. no. e136, 2024

EN

Aluminum alloy parts are widely used in aerospace and other fields due to their light weight and good corrosion resistance. However, during the forming process, uneven deformation can lead to high residual stresses and low forming accuracy in the parts, ultimately seriously affecting the subsequent service performance. In this study, the influence of the cryogenic-vibration compound field on the residual stresses, microstructural evolution, and forming accuracy were investigated based on the deep drawing experiment of aluminum alloy cylindrical parts. The results indicate that when compared to the absence of cryogenic and vibration, the compound field can reduce residual stresses in the parts by 22%, which is attributed to lower dislocation density and more uniform distribution of low-angle grain boundaries. The cryogenic environment can weaken the degree of dislocation entanglement in low-angle grain boundaries, meanwhile, the dislocations are easily dissociated and released under the vibration. The maximum sidewall thickness difference, the sidewall height difference, and the surface roughness decrease by 68, 69, and 52%, respectively, which is due to the uniform distribution of microstructure and the reduction of frictional resistance caused by the boiling liquid nitrogen. This study provides a new method for the forming of high-quality aluminum alloy parts.

15

Effect of Regular Shot Peening and Semi-Random Shot Peening Conditions on Selected Properties of the Surface Layer of Gray Cast Iron

Skoczylas Agnieszka, Zaleski Kazimierz

Advances in Science and Technology. Research Journal

|

2024

|

Vol. 18, no. 2

284--295

EN

Both dispersed and concentrated shot peening can be an effective method for the finishing of machine components. This work investigates the effect of two different shot peening (SP) processes conducted with the same technological parameters on selected properties of the surface layer of gray cast iron EN-GJL 250. Specifically, regular shot peening (RSP) and semi-random shot peening (SRSP) were investigated in the study. The results demonstrated that the surface quality of EN-GJL 250 samples was higher after RSP than after SRSP. The analyzed surface roughness parameters were lower after RSP than after SRSP, with the exception of the Rvk parameter. As a result of RSP, the analyzed roughness parameters increased from 5% to 62% in relation to their values after pre-treatment. The lowest values of the surface roughness parameters were obtained after RSP conduced with the impact energy E = 100 mJ, the distance between the dimples x = 0.3 mm, and the diameter of the shot peening element d = 14.3 mm. Assessment of the 3D surface topography showed significant differences in the formation of machining traces depending on the employed surface treatment. In RSP, the traces were arranged in a uniform manner, with the assumed step, whereas in SRSP the shot peening traces had no set pattern of orientation. The application of RSP and SRSP caused an increase in surface microhardness. The maximum surface microhardness was 75 HV0.5 for RSP and 98 HV0.5 for SRSP. Residual stresses were higher after SRSP than after RSP. Compressive residual stresses were induced in both types of shot peening process.

16

Numerical investigation of indentation-induced residual stresses and their effect on J-integral and crack propagation

Baltach Abdelghani, Khelil Foudil, Djebli Abdelkader, Benhamena Ali, Chaouch Mohamed Ikhlef, Bendouba Mostefa

Advances in Materials Science

|

2024

|

Vol. 24, nr 2(80)

21--34

EN

This work presents an analysis of the effect of ball indentation on fatigue crack growth. The main objective is to assess the effectiveness of indentation, particularly its influence on the J-integral, as a fracture criterion governing fracture toughness. Using the finite element method in Abaqus 6.14, we analyzed the residual stresses induced by indentation at different positions along the predicted line of crack propagation and calculated the J-integral. The results highlight that indentation at the crack tip position significantly reduces the J-integral compared to non-indented structures, demonstrating its potential to extend the lifespan of cracked components by delaying crack propagation. The findings underscore the practical application of ball indentation as a viable technique to retard crack growth, contributing to the longevity of cracked components and, consequently, structural integrity. This analysis revealed a crack propagation retardation gain of up to 56%.

17

Numerical modelling and simulation of the shear-slitting process of electrical steels

Bohdal Łukasz, Kułakowska Agnieszka, Kułakowski Marcin

Acta Mechanica et Automatica

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2024

|

Vol. 18, no. 2

341--351

EN

Despite the development of laser processing, the mechanical cutting process is still widely used in the formation of electric steels that are very sensitive to thermal phenomena. However, proper process control is difficult due to the large number of factors determining the quality of the products. As a result, the quality of the cut edge is characterised by the presence of burrs, the removal of which increases the production costs. Due to their magnetic properties, these materials should not be exposed to excessive stresses and deformations. The article presents the possibilities of predicting the characteristic features of the cut edge as well as stress distributions in this area. Original shear-slitting finite element method (FEM) models were developed, the results of which were verified experimentally. The proposed method based on stress triaxiality analysis enables precise analysis of stress states in the cutting zone and the boundaries of the slip fracture transition in the separating fracture, as well as determining the method of material cracking. Variable control factors such as cutting clearance, rake angle of the upper knife, and cutting speed were taken into account in the models. Parametric analysis of the process was carried out and it was determined how the process parameters should be selected in order to obtain the appropriate quality of the product. The developed analysis results can be useful on production lines for proper process control.

18

Correlation between printing parameters and residual stress in additive manufacturing: a numerical simulation approach

Alzyod Hussein, Ficzere Péter

Production Engineering Archives

|

2023

|

Vol. 29, Iss. 3

279-287

EN

Fused Deposition Modeling (FDM) is a widely used 3D printing technology that can create a diverse range of objects. However, achieving the desired mechanical properties of printed parts can be challenging due to various printing parameters. Residual stress is a critical issue in FDM, which can significantly impact the performance of printed parts. In this study, we used Digimat-AM software to conduct numerical simulations and predict residual stress in Acrylonitrile Butadiene Styrene (ABS) material printed using FDM. We varied six printing parameters, including printing temperature, printing speed, and infill percentage, with four values for each parameter. Our results showed that residual stress was positively correlated with printing temperature, printing speed, and infill percentage, and negatively correlated with layer thickness. Bed temperature did not have a significant effect on residual stress. Finally, using a concentric infill pattern produced the lowest residual stress. The methodology used in this study involved conducting numerical simulations with Digimat-AM software, which allowed us to accurately predict residual stress in FDM-printed ABS parts. The simulations were conducted by systematically varying six printing parameters, with four values for each parameter. The resulting data allowed us to identify correlations between residual stress and printing parameters, and to determine the optimal printing conditions for minimizing residual stress. Our findings contribute to the existing literature by providing insight into the relationship between residual stress and printing parameters in FDM. This information is important for designers and manufacturers who wish to optimize their FDM printing processes for improved part performance. Overall, our study highlights the importance of considering residual stress in FDM printing, and provides valuable information for optimizing the printing process to reduce residual stress in ABS parts.

19

Investigation of additive manufactured micro-lattice structures for defence applications

Shaik Ameer Malik, Reddy Bobbili Veera Siva, Sastry C. Chandrasekhara, Krishnaiah J., Ramakrishna B.

Materials Science Poland

|

2023

|

Vol. 41, No. 2

383--400

EN

This study investigates the blast mitigation capabilities of A286 steel micro-lattice structures produced through additive manufacturing. The research explores the effects of different manufacturing conditions, such as stress relief and heat treatment, on the mechanical properties and blast resistance of honeycomb and gyroid lattice structures in correlation with armour steel structures. Comprehensive evaluations, including surface morphology, corrosion resistance, and compressive residual stress analysis, reveal notable findings for micro-lattice structures. Micro-lattice structures demonstrated 57.23% higher corrosion resistance compared to conventional materials, presently available in the form of rolled homogeneous armour, medium hardness armour, and high-nitrogen steel. Additionally, honeycomb lattice structures exhibit compressive residual stresses of up to 581.90 MPa, providing significant advantages in blast mitigation potential. These results underscore the significance of lattice geometry, material microstructure, and residual stress in enhancing blast resistance. The research offers valuable insights into optimizing additive manufactured structures as an alternative modular solution for defence applications.

20

Study on the stress intensity factor of a compact specimen under the pre-compressed load condition

Wu Dongquan, Liu Zixiang, Li Dinghe, Zhang Zhiqiang, Chen Jianguo

Journal of Theoretical and Applied Mechanics

|

2023

|

Vol. 61 nr 1

37--47

EN

Structural components are often operated under combined stress conditions (primary and secondary stresses), but the stress levels generated by residual stress (or secondary stress) is hardly ever evaluated. Hence, stress intensity factors at the crack tips of a compact tension (CT) specimen under a pre-compressed load condition are analyzed using the finite element method. Then, the average residual stress intensity factor is calculated and analyzed. As the crack length α0/W increases, the average residual stresses σave/σ0 grows under the same pre-compression load. σave/σ0 increases rapidly at a low range of the pre-compression load but tends to a constant in a high range of the load. The distribution of the average residual stress intensity factors Kave and Κave/σ0 of the CT specimen with same crack length under different pre-compression loads have the same tendency. Additionally, the distribution of Κave and KFEM under different pre-compression loads are also similar. Nevertheless, Kave estimated by the average residual stress is too conservative and not accurate, and the method is complex, which depends on the analysis of simulation. Therefore, a simple method for calculating Mode I stress intensity factor K for this model is presented. A group of examples is presented to verify the accuracy of the method.