Element Stress Research Articles

Finite element stress analysis of dental cement application on endocrown and onlay restoration.

The aim of the study was to evaluate the influence of resin cement material types on tooth with endocrown and onlay restorations. The first molar was scanned using Micro-CT and underwent a modelling process to obtain the 3D model for computational simulation. Eight models were simulated in the current study with two loading conditions (720N vertical load and 200N oblique load), two types of restoration (onlay and endocrown restorations), and two resin cement variants (dual-cure resin cement and light-cure resin cement). The tooth with onlay restoration showed a significant stress reduction (up to 70%) when using light-cure resin cement compared to dual-cure resin cement. In contrast, types of cement did not affect stress distribution in the tooth with endocrown restoration. The current study found that dual-cure resin cement was preferable in Endocrown and Onlay restorations, due to dual-cure resin cement provided better bond strength compared to light-cure resin cement.

Three-dimensional finite element stress analysis of surface-mounted inlays in repairing pulp-penetrating non-carious cervical lesion of maxillary first premolar.

This study aimed to explore the stress distribution of surface-mounted inlays with two ceramic materials and different strategies for fiber post-restoration on pulp-penetrating non-carious cervical lesion in a maxillary first premolar to provide minimally invasive and reasonable restorative methods. The cone beam computed tomography data of the standard right upper first premolar were selected. Healthy control (HC) and defective control (DC) finite element models were established. Then, eight experimental models were established according to two different ceramic materials (IPS e.max CAD [LD] and Lava Ultimate [LU]) and different locations of fiber post (without fiber post [NP], fiber post in buccal root canal [B], fiber post in palatal root canal [P], fiber post in both root canals [BP]), namely, LDNP, LDB, LDP, LDBP, LUNP, LUB, LUP, and LUBP. Axial load F1 and lateral load F2 were applied. Maximum principal stress and displacement of the buccal tip were investigated using finite element analysis software. Then, the percentage change of the following indicators in each experimental group was analyzed: stress of defective tip with group DC, stress of enamel and dentine, and displacement of buccal tips with group HC. It was considered similar when the percentage change was less than 5%. LD and LU groups could effectively reduce the stress of the defective tip, but the decreasing amplitude in the former was greater than that of the latter. For the stress of surface-mounted inlays and resin adhesive layer, LD groups were higher than LU groups, and no significant difference in stress peak was found among different experimental groups in the same material. In addition, fiber posts in double root canals could significantly reduce buccal tip displacement. For pulp-penetrating non-carious cervical lesions, the restorative strategy of surface-mounted inlays could be applied. Compared with Lava Ultimate, IPS e.max CAD could better protect the defective tip tooth. Furthermore, fiber posts in double root canals could decrease overall deformation and increase the retention of surface-mounted inlays.

Effect Of Hardening On Germination And Seedling Characters Of Maize (Zea Mays L)

The ideal temperature is necessary for the maize crop to provide the highest harvest yield. Environmental stress elements such as abiotic and biotic stress factors are expected to intensify and become more widespread as a result of climate change. Drought, temperature, and salinity are the key factors affecting maize output globally. Various management practices may help in contributing tolerance to the plants against adverse environmental impact, and seed hardening is one among them. The experiment was conducted in the laboratory of Seed science and Technology, Department of Agriculture, Kalasalingam School of Agriculture and Horticulture, Krishnankoil, Tamil Nadu to study the effect of various hardening treatments in maize seeds. Maize seeds were hardened with the following chemicals at varying concentrations for 12 hours viz., T0 – Control, T1 – Distilled water, T2 – Boric acid (0.5%), T3 – Boric acid (1.0%), T4 – Boric acid (1.5%), T5 – KNO3 (0.5%), T6 – KNO3 (1.0%), T7 – KNO3 (1.5%), T8 – KH2PO4 (0.5%), T9 – KH2PO4 (1.0%) and T10 – KH2PO4 (1.5%). Significant differences were found between control and hardening treatments. Maximum germination percentage, shoot, and root length, seedling length, fresh and dry weight of the seedling vigor index were observed for the seeds treated with 1.5% KNO3. This experiment also showed the positive influence of KH2PO4 (1.5%) in various seedling characters followed by 1.5% KNO3. This study might help to improve the seedling character with the help of seed-hardening treatments to withstand adverse abiotic stress situations

Monitoring the technical state of load-bearing structures of the Luzhniki Stadium during reconstruction

Introduction. The paper presents the methods of reinforcing brick-and-stone structures, as well as monitoring of their strain capacity during the reconstruction of the Grand Sports Arena of Luzhniki Olympic Complex. The authors paid special attention to the methods for ensuring the preservation of front wall made of ceramic hollow stones.Aim. To ensure the reliability and stability of the wall of the Grand Sports Arena during the stadium reconstruction, in particular during the dismantling of the framework and stands.Materials and methods. The authors calculated the strain capacity (vertical deviation) of the framework of the stands at its dismantling stage and the wall stability, taking into account the framework fastening with rolled steel braces. The wall section taken for calculation at the first stage of dismantling stands consisted of several spans of 6 meters each. An extreme wind action was considered as the main stress factor that has the most severe impact on the front wall strain.Results. The calculations showed that the wind load on the system “front wall + 1 span of the stand framework” increases tensile and compressive stresses in the load-bearing elements by no more than 5–7% compared to the system “front wall + 2 spans of the stand framework”. Based on the calculations performed, only one span of the stand framework adjacent to the front wall was decided to retain. Monitoring of the structures strain confirmed the reliability and efficiency of the adopted solutions to strengthen the retained structures.Conclusion. Due to R&D support for the design and reconstruction of the Luzhniki Grand Sports Arena, complex issues arising in the process of reconstruction were efficiently solved. The principles of the Arena reconstruction can be applied to other similar facilities.

Explicit Method in the Seismic Assessment of Unreinforced Masonry Buildings through Plane Stress Elements

The complex nonlinear behaviour of unreinforced masonry (URM), along with the interaction between structural elements, still represents a challenge for the seismic assessment of existing URM buildings. A large variety of mathematical tools have been developed in the last decades to address the issue. The numerical work herein presented attempts to provide some insights into the use of FEM models to obtain reliable results from nonlinear dynamic analyses conducted with explicit methods. Through plane stress elements, two in-plane mechanisms were studied to identify optimal parameters for unreinforced masonry elements subjected to dynamic actions. The results were then compared with outcomes generated by an implicit solver. Subsequently, these parameters were used in nonlinear dynamic analyses on a building section for the seismic assessment in both unreinforced and reinforced conditions. The element type, hourglass control, damping, and bulk viscosity influence the dynamic response, mainly when the nonlinearities become larger. The hourglass control techniques employ a scaling factor to suppress the occurrence of spurious modes. Values ranging from 0.01 to 0.03 have shown effective results. When the stiffness-damping parameter for Rayleigh damping is of a similar order of magnitude or lower than the time increment without damping, the time increment remained in feasible ranges for performing analysis. Additionally, the bulk viscosity can stabilise the response without causing substantial alterations to the time increment if the values are under 1.00.

Prosedur Pemeriksaan MRI Lumbal pada Kasus Efusi Pleura Suspek Tuberkulosis

Background: Clinical vertebral tuberculosis (TB) occurs outside the lungs affecting the spine. It generally infects the spine in the lower thoracic and upper lumbar spine. MRI examination is performed on clinical vertebral TB patients to determine the degree of stress and changes in bone elements in the early stages of the disease. This study aims to analyze the lumbar MRI examination procedure in cases of suspected TB pleural effusion. Methods: This research was qualitative with a case study approach. Data collection was carried out at the Radiology Unit of Premier Bintaro Hospital with the methods of observation, interviews, and documentation. Data processing and analysis were carried out descriptively. Results: Lumbar MRI examination with suspected TB pleural effusion at the Radiology Unit of Premier Bintaro Hospital was not specially prepared, the patient was examined first through the patient checklist to avoid metal materials entering the examination room. Examination using the Non-Contrast Lumbar MRI protocol included of sagittal and coronal T2, sagittal T1, sagittal Short Tau Inverse Recovery (STIR), Myelography, Axial T2, and Axial T1. The results of the examination provided sufficient diagnostic information to indicate a vertebral TB lesion. Conclusions: The procedure for examining lumbar MRI in TB cases with suspected pleural effusion at the Radiology Unit of Premier Bintaro Hospital did not require special preparation, the examination protocol used was to provide TB clinical diagnostic information, the addition of Gadolinium contrast media could be an alternative choice.

Mineral elements and adiposity-related consequences in adolescents with intellectual disabilities

BackgroundPatients with intellectual disabilities are shown to have a limited capacity for cooperation, communication,and other biological consequences, which significantly require a specialized interest in healthcare professionals worldwide.AimIn this respect, the present study was designed to evaluate the levels mineral elements, and their correlation with oxidative stress markers and adiposity markers; leptin (L), adiponectin (A), and L/A ratio in adolescents with intellectual disabilities.MethodsA total of 350 schoolchildren aged (12–18 years) were randomly invited to participate in this prospective, observational study. Only 300 participants agreed to participate in this study. According to Intelligence quotients scores (IQ) measured by WISC-III, the participants were classified into two groups; the healthy control group (no = 180; IQ = 90–114); and the moderate intellectual disability (MID) group (no = 120; IQ = 35–49). Adiposity markers; body mass index (BMI), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), physical activity scores, adipokines biomarkers; leptin, adiponectin, L/A ratio, oxidative stress, and plasma mineral elements were evaluated by prevalidated questionnaires, inductively coupled plasma-mass spectrometry (ICP-MS), colorimetric, and immunoassay techniques.ResultsIntellectual disability of moderate type was reported in 40% of the studied populations most of them are men aged 12–18 years (66.6% for men vs. 33.3 for females). Obesity was shown to be associated with the degree of intellectual disability of the students. There was a significant (P = 0.001) increase in the BMI, WHR, and WHtR scores as obesity markers with poor physical activity (P = 0.01) in students with poor disability compared to healthy controls (HC). The levels of leptin (P = 0.001), adiponectin (P = 0.01), and L/A ratio (P = 0.01) as adiposity biomarkers were significantly increased in students with MID compared to healthy controls. Also, oxidative stress measured by malondialdehyde (MDA) (P = 0.01) and total antioxidant capacity (TAC) (P = 0.01) were significantly increased in students with MID compared to healthy control subjects. In addition, mineral elements were shown to be linked with intellectual disability. The data showed that the levels of Fe, Mn, Zn, Hg, Pb, Ca, Cr, Mg, and Ni significantly (P = 0.001) increased, and the levels of Al, Na, K, Cu, and Zn/Cu ratio significantly (P = 0.001) decreased in subjects with MID compared to healthy controls. Correlation analysis concluded that changes in mineral elements significantly correlated with adiposity markers, oxidative stress, and the scores of intellectual disability (WISC III-IQ score).ConclusionThe intellectual disability of moderate type (MID) was associated with abnormal changes in the levels of essential mineral elements and adipokines and increased levels of cellular oxidative stress. Thus, evaluating plasma mineral elements and adipokines levels could be a potential diagnostic parameter for diagnosing MID.

Failure characteristics and service life prediction of polycrystalline diamond compact (PDC) cutter under cyclic impact loading

This paper aims to investigate the cyclic impact damage characteristics and service life of PDC cutters under varying impact loadings, angles, and depths. Additionally, a life prediction model is established to predict the fatigue life of flat cutters, axe cutters, and triangular cutters. A customized impact test device was utilized to conduct the cyclic impact test, and a finite element model was calibrated based on the experiment result of flat PDC cutter. Then, the model was used to analyze the stress distribution in the axe and triangular cutters, respectively. By combining the experimental and numerical results, the S–N (Stress-Number of times) curve representing the fatigue failure of the PDC cutter substrate was established. Moreover, the fatigue life of different PDC cutters under impact loading was predicted by integrating the S–N curve with the results of finite element stress analysis. The findings indicate that triangular cutters exhibited the longest fatigue life, with a 30.36% increase compared to flat cutters, under an impact angle of 15°, an impact depth of 4 mm, and an impact loading of 7616N. Similarly, the fatigue life of axe cutters was 7.59% higher than that of flat cutters. These findings suggest that non-flat cutters have greater impact resistance and are more suitable for heterogeneous strata characterized by significant impact stress variations.

Functional characterization of the IGT gene family in wheat reveals conservation and variation in root architecture under drought condition

Plant architecture traits are a pivotal component in crop improvement and one of the key aspects of breeding programs for centuries. Among architecture traits, leaves and roots angle are most important whereas roots angle is considered to play a vital role in plant response to drought avoidance. Several genes regulating drought response reported in plants, such as LAZY1, Deeper Rooting 1 (DRO1), and Tiller angle control 1 (TAC1), belong to the IGT family. The wheat (Triticum aestivum L.) genome is complex because it consists of three subgenomes A, B, and D. A genome-wide (A, B, and D) identification and characterization of IGT family genes in wheat was reported in this study. A total of 12 IGT genes were identified and categorized based on phylogenetic reconstruction and gene structure analysis. These genes were distributed on chromosomes 2, 5, and 6 corresponding to the A, B, and D genomes of wheat. Most of the genes showed similar structures. Cis-regulatory elements in the promoter regions interpreted the presence of light, stress, development, and hormone-related elements. Five miRNAs (tae-miR9773, tae-miR531, tae-miR9678–3p, tae-miR9781, and tae-miR5049–3p) were predicted which target these TaIGT. Both the RNA-seq-based transcriptomic and real-time gene expression analysis suggested that all the genes are strongly expressed in roots, thus showing function conservation. 3D models and molecular docking of TaIGT were also carried out systematically, and binding patterns and the orientation of ligands in the active site of proteins were predicted. This study delves further into TaIGT genes and their expression patterns. The findings of this work are important for understanding the molecular control of root development and for future functional characterization of wheat root architecture genes. Key messageIGT gene family has not been identified and characterized and we identified 12 genes strongly expressing in roots. Furthermore, five miRNAs were predicted and could have a role in root conservation.

Development and Factorial Validation of an Instrument for Measuring Executive Stress among Nigerian Oil Company Workers in Rivers State, Nigeria

This study was designed to develop and factorially validate an instrument, Executive Stress Measurement Scale (ESMS) for measuring executive stress among Nigeria oil company workers in Rivers State. The study was instrumentation. Sample consisted of 120 executive workers. Four major constructs that constitute the elements of executive stress were identified. The four sub-scales are symptoms and main causes of executive stress, nature of job stress and work-load. 108 items drafted instrument was presented to two specialists and 5 experts for face validation. Ninety items survived the exercise. The 90 items were administered to executive workers in three Nigerian oil companies in Rivers State. Data collected from the field were subjected to factor analysis. 55 items after factor analysis were found to be well loaded. Cronbach alpha was used to determine the reliability of ESMS of 55 items. 0.89 reliability coefficients were obtained for the entire items and 0.86, 0.82, 0.81 and 0.70 for each factor. Further analysis was done to the data using factor analysis, correlation and t- test statistics. Validity of the ESMS is 0.80. Recommendations includes; that ESMS should be use by the Rivers State Education Commission, Directorate of Petroleum Resources, School Researchers, Oil Company Workers among others.

Optimal design of semi-rigid connection steel frame with infilled shear walls using dolphin echolocation algorithm

In this paper, the dolphin echolocation algorithm (DEA) was applied for optimization. Two different two-dimensional semi-rigid connection steel frames with infilled shear walls (SFIWs) were optimized to obtain the minimum weight with constraints on the element stresses and storey drift ratio according to the American Institute of Steel Construction (AISC) Load and Resistance Factor Design requirements. With the proposed method, the specific details of the infilled shear walls are not given during the design process, but are characterized by the lateral stiffness. The designer can decide which types of infilled shear walls are used according to the result obtained from the optimization. The infilled shear walls are modeled as braces with equivalent lateral stiffnesses, while the semi-rigid connections are used to obtain the practical behaviors of the SFIWs. The results demonstrate that the proposed method is suitable for optimizing semi-rigid connection steel frames with infilled shear walls.

The effect of the degree of cracking on the state of stress and cracks width in elements with restrained boundary conditions

AbstractA new and more precise model of cracking of reinforced concrete elements subjected to imposed strains is presented. A key question is how in the stress classic approach to take account of the effect of element relaxation (after each cracking episode) on cracks width reduction and other cracking criteria. Such a model would enable the calculation of the maximum cracks width depending on the cracking stage (i.e., the stage of cracks formation or that of stabilized cracks). This phenomenon is important particularly in semi‐massive structures in which the condition of watertightness must be fulfilled. The model has been validated based on the experimental studies available in the literature. For higher levels of strain the cracks widths have been found seriously underestimated after European standards (especially in elements with higher reinforcement ratio) while the calculations performed following the proposed model indicate proper estimation of cracks width.

A Reissner–Mindlin plate formulation using symmetric Hu-Zhang elements via polytopal transformations

In this work we develop new finite element discretisations of the shear-deformable Reissner–Mindlin plate problem based on the Hellinger–Reissner principle of symmetric stresses. Specifically, we use conforming Hu-Zhang elements to discretise the bending moments in the space of symmetric square integrable fields with a square integrable divergence M∈HZ⊂Hsym(Div). The latter results in highly accurate approximations of the bending moments M and in the rotation field being in the Lebesgue space ϕ∈[L2]2, such that the Kirchhoff–Love constraint can be satisfied for t→0. In order to preserve optimal convergence rates across all variables for the case t→0, we present an extension of the formulation using Raviart–Thomas elements for the shear stress q∈RT⊂H(div).We prove existence and uniqueness in the continuous setting and rely on exact complexes for inheritance of well-posedness in the discrete setting.This work introduces an efficient construction of the Hu-Zhang base functions on the reference element via the polytopal template methodology and Legendre polynomials, making it applicable to hp-FEM. The base functions on the reference element are then mapped to the physical element using novel polytopal transformations, which are suitable also for curved geometries.The robustness of the formulations and the construction of the Hu-Zhang element are tested for shear-locking, curved geometries and an L-shaped domain with a singularity in the bending moments M. Further, we compare the performance of the novel formulations with the primal-, MITC- and recently introduced TDNNS methods.

Analysis of the Tomato mTERF Gene Family and Study of the Stress Resistance Function of SLmTERF-13.

Mitochondrial transcription termination factor (mTERF) is a DNA-binding protein that is encoded by nuclear genes, ultimately functions in mitochondria and can affect gene expression. By combining with mitochondrial nucleic acids, mTERF regulates the replication, transcription and translation of mitochondrial genes and plays an important role in the response of plants to abiotic stress. However, there are few studies on mTERF genes in tomato, which limits the in-depth study and utilization of mTERF family genes in tomato stress resistance regulation. In this study, a total of 28 mTERF gene family members were obtained through genome-wide mining and identification of the tomato mTERF gene family. Bioinformatics analysis showed that all members of the family contained environmental stress or hormone response elements. Gene expression pattern analysis showed that the selected genes had different responses to drought, high salt and low temperature stress. Most of the genes played key roles under drought and salt stress, and the response patterns were more similar. The VIGS method was used to silence the SLmTERF13 gene, which was significantly upregulated under drought and salt stress, and it was found that the resistance ability of silenced plants was decreased under both kinds of stress, indicating that the SLmTERF13 gene was involved in the regulation of the tomato abiotic stress response. These results provide important insights for further evolutionary studies and contribute to a better understanding of the role of the mTERF genes in tomato growth and development and abiotic stress response, which will ultimately play a role in future studies of tomato gene function.

Identification of overloads on splined shafts by means of eddy current testing technology

For the development of resource-efficient machines, the availability of high-quality information about the actual loads that occur is a key prerequisite. By continuously monitoring the loads on the component, critical events can be detected, and thus component failure prevented. Future product generations can also be designed in a resource-saving way depending on the loads that actually occur. The information is most useful when it is obtained directly from the highly loaded areas of the component. In this study, a concept is presented that enables in-situ detection of mechanical overloads on splined shafts by eddy current techniques. Splined shaft connections are among the most heavily stressed machine elements in the drive train and are usually located centrally in the powertrain. To monitor mechanical overloads, a material-integrated sensor will be developed. The structural change that takes place in the sensor as a result of overloads can be monitored with the help of eddy current testing technology. To ensure permanent monitoring of the sensor area, a compact eddy current testing system has to be integrated into the component. This consists of a printed circuit board coil, an evaluation unit, a data transmission module and an energy-harvesting module. The measurement principle for the stainless steels employed is based on the microstructural transformation from metastable austenite to martensite when the material is stressed beyond a threshold value. The threshold at which the structural transformation occurs can individually be adjusted in the sensor area by a local laser heat treatment.

Formal Social Control and Mental Health: Ethnic Variation among Black Women

The present study uses elements of the social stress and intersectionality theories to examine associations between forms of criminal justice contact and mental health among African American and Afro-Caribbean women. While mass incarceration disproportionately targets, detains, and affects Black populations, the experiences and consequences of criminal justice contact for Black women remain understudied. Utilizing the National Survey of American Life ( n = 3,011), this study examined ethnic-stratified associations between criminal justice contact and three mental health indicators among Black women—psychological distress, self-rated mental health, and post-traumatic stress disorder (PTSD). We assessed justice contact based on any contact (i.e., direct contact and/or family member incarceration), and then disaggregated contact into direct (i.e., personally experienced negative police interactions, arrests, and incarceration) and familial incarceration. Findings showed that any contact as well as direct forms of contact were associated with higher psychological distress for African American women and odds of PTSD for both groups. Furthermore, negative police interactions and family member incarceration were associated with psychological distress for African American women, while only familial incarceration worsened self-rated mental health for Afro-Caribbean women. This study yields important insights for research at the intersection of gender-ethnic status, spillover outcomes of formal social control, and mental health stratification.

Characterizing experiential elements of early-life stress to inform resilience: Buffering effects of controllability and predictability and the importance of their timing.

Key theoretical frameworks have proposed that examining the impact of exposure to specific dimensions of stress at specific developmental periods is likely to yield important insight into processes of risk and resilience. Utilizing a sample of N = 549 young adults who provided a detailed retrospective history of their lifetime exposure to numerous dimensions of traumatic stress and ratings of their current trauma-related symptomatology via completion of an online survey, here we test whether an individual's perception of their lifetime stress as either controllable or predictable buffered the impact of exposure on trauma-related symptomatology assessed in adulthood. Further, we tested whether this moderation effect differed when evaluated in the context of early childhood, middle childhood, adolescence, and young adulthood stress. Consistent with hypotheses, results highlight both stressor controllability and stressor predictability as buffering the impact of traumatic stress exposure on trauma-related symptomatology and suggest that the potency of this buffering effect varies across unique developmental periods. Leveraging dimensional ratings of lifetime stress exposure to probe heterogeneity in outcomes following stress - and, critically, considering interactions between dimensions of exposure and the developmental period when stress occurred - is likely to yield increased understanding of risk and resilience following traumatic stress.

A mechanical HSA biosensor based on multi-field-coupling-mediated magnetic sensitization strategy

The conventional mechanical biosensor based on stress and electrical conversion can be an effective method to detect key human biomarkers for clinical diagnosis and early disease prevention. However, the applications of this type of biosensor are greatly limited due to their unsatisfactory sensitivity. In this work, a magnetic-sensitized (MS) mechanical biosensor based on multi-field coupling was developed for higher sensitivity, giving access to detect human serum albumin (HSA). Via introducing secondary magnetic antibodies labeled with magnetized Fe2O3 nanoparticles to the stress and electrical conversion element of the MS-biosensor, the multi-field coupling was realized based on stress, electricity, and magnetism. Under the action of the magnetic field, the magnetic force of the secondary magnetic antibody and the stress of antigen-antibody binding jointly drove and enhanced the deformation of the MS-biosensor, amplifying the electrical signal, and realizing magnetic sensitization. The HSA was detected by the MS-biosensor at a range of 0–80 μg/mL with a limit of detection (LOD) of 0.14 μg/mL, demonstrating the high performance of the MS-biosensor. Moreover, the MS-biosensor showed high selectivity, specificity, and stability, indicating that the magnetic sensitization strategy of the MS-biosensor was significant for the clinical application of mechanical biosensors.

Finite Element Simulation and Stress Analysis of Gas Turbine Blade Due to Centrifugal Force

Gas turbine always consider one of the most important system in the modern engineering applications, because it has continuous ability to generate electric power. In gas turbines the major portion of performance dependency lies upon turbine blade design ,the blades are considered one of the important and expensive parts in the gas turbines , where the blades of first stage from failure . Most studies indicate that 50% of failure and breakage accidents cannot be accurately determined due to the large number of variables .The blades of the gas turbine suffer from tensile stresses due to centrifugal forces resulting from the high rotational speed and because of the loading of dense gasses at a high temperature and speed ,as the centrifugal force is one of the problems that the designer of the turbine blades faces , as the designer aims to reduce stresses within the permissible limit . The current work is concerns with study and analysis of the stresses at the first stage blades in Al Mosul power station at Mosul city, AUTOCAD which is computer program has been an efficient software to draw and specify blade dimensions at the exact measurement, as well as the ANSYS 21 software program was also used as an effective tool in determining the stresses and deformation under the influence of centrifugal force. As the blade was considered root bound in all direction (X, Y and Z) and adding the special mechanical properties of (INCONEL738 alloy), After conducting a stress analysis in the program, it was found that the stress values of the posterior and anterior edge of the blade root region were high and these results were validated with the results carried out by some studies that dealing with study and analysis of the blades at the first stages in turbine stations. The static and modal analysis of the turbine blade is being considered. To analyze these aspects, the blade is represented using the 3D-Solid Brick element. The blade's geometric model is created by generating and then extruding them to form a solid model. An analytical approach is utilized to estimate the centrifugal forces. The objective of this presented work is to investigate the impact of mechanical analysis on the structure of gas turbine blades. The findings indicate lower levels of mechanical stress.

Investigation of Auxetic Structural Deformation Behavior of PBAT Polymers Using Process and Finite Element Simulation.

The current work investigates the auxetic tensile deformation behavior of the inversehoneycomb structure with 5 × 5 cells made of biodegradable poly(butylene adipate-coterephthalate) (PBAT). Fused deposition modeling, an additive manufacturing method, was used to produce such specimens. Residual stress (RS) and warpage, more or less, always exist in such specimens due to their layer-by-layer fabrication, i.e., repeated heating and cooling. The RS influences the auxetic deformation behavior, but its measurement is challenging due to its very fine structure. Instead, the finite-element (FE)-based process simulation realized using an ABAQUS plug-in numerically predicts the RS and warpage. The predicted warpage shows a negligibly slight deviation compared to the design topology. This process simulation also provides the temperature evolution of a small-volume material, revealing the effects of local cyclic heating and cooling. The achieved RS serves as the initial condition for the FE model used to investigate the auxetic tensile behavior. With the outcomes from FE calculation without consideration of the RS, the effect of the RS on the deformation behavior is discussed for the global force-displacement curve, the structural Poisson's ratio evolution, the deformed structural status, the stress distribution, and the evolution, where the first three and the warpage are also compared with the experimental results. Furthermore, the FE simulation can easily provide the global stress-strain flow curve with the total stress calculated from the elemental stresses.