Dynamic Finite Element Analysis Research Articles

Biomechanics of calcaneus impacted by talus: a dynamic finite element analysis

This paper aimed to investigate the biomechanical changes during the talus impact with the calcaneus at varying velocities. Various three-dimensional reconstruction software was utilized to construct a finite element model that consisted of the talus, calcaneus, and ligaments. The explicit dynamics method was used to explore the process of the talus impacting on the calcaneus. The velocity of impact was altered from 5 m/s to 10 m/s with a 1 m/s interval. Stress readings were collected from the posterior, intermediate, and anterior subtalar articular (PSA, ISA, ASA), calcaneocubic articular (CA), Gissane Angle (GA), calcaneal base (BC), medial wall (MW), and lateral wall (LW) of the calcaneus. The changes in the amount and distribution of stress in the different regions of the calcaneus that varied with velocity were analysed. The model was validated through comparison with findings from the existing literature. During the process of impact between the talus and calcaneus, the stress in the PSA reached its peak first. Notably, stress was concentrated mainly in the PSA, ASA, MW, and LW of the calcaneus. At varying impact velocities of the talus, the mean maximum stress of the PSA, LW, CA, BA, and MW exhibited statistically significant differences (P values were 0.024, 0.004, <0.001, <0.001, and 0.001, respectively). However, the mean maximum stress of the ISA, ASA, and GA was not statistically significant (P values were 0.289, 0.213, and 0.087, respectively). In comparison with the velocity at 5 m/s, the mean maximum stress increases in each region of the calcaneus at a velocity of 10 m/s were as follows: PSA 73.81%, ISA 7.11%, ASA 63.57%, GA 89.10%, LW 140.16%, CA 140.58%, BC 137.67%, MW 135.99%. The regions of stress concentration were altered, and the magnitude and sequence of peak stress in the calcaneus also varied according to the velocity of the talus during impact. In conclusion, the velocity of the talus during impact had a significant influence on the magnitude and distribution of stress within the calcaneus, which was a crucial factor in the development of calcaneal fractures. It was possible that the magnitude and sequence of stress peaks played a vital role in determining the emergence of fracture patterns.

Numerical modeling of ice–seabed interaction in layered soil: stiff over soft clay

This study presents a numerical investigation of free field ice gouging in layered cohesive seabeds comprising stiff over soft clay. A three-dimensional, half-space, dynamic large deformation finite element analysis was conducted using the Coupled Eulerian Lagrangian approach. To simulate the seabed, a Tresca soil model with the strain rate and strain-softening effects was coded into a user subroutine. The accuracy of the model was verified by comparing its results with those of published experimental studies. Additionally, a comprehensive parametric study was conducted to examine the effect of various ice gouging scenarios and seabed soil parameters on the subgouge soil deformation and the ice keel reaction forces. Our findings revealed that an interactive response occurs between the soil layers and the ice keel that may cause the peak subgouge soil deformation and keel reaction magnitudes to differ from those observed under uniform soil condition. The developed model was found to be an efficient tool for free field ice gouging analysis in cohesive layered seabeds.

An efficient equivalent static methodology for simulating electronic packages subjected to resonant vibrations

Modeling of electronic packages under vibrations is quite an interesting and important problem. The Finite element method (FEM) is the most common tool that is used in simulating the vibration-induced deformations and stresses of electronics. Therefore, this paper aims to present an equivalent static solution, instead of the dynamic solution, to simulate this mechanical problem. Towards this goal, the mathematical derivation of the equivalent static loading is thoroughly discussed. This analytical derived solution is then validated with the results of experimentally acquired data and with dynamic finite element analysis (FEA) simulations in terms of the board transverse deflections and solder array stresses. The validation study showed great agreement with all solutions. The validity of this approach is certified through a case study. Thus, the use of the equivalent static loading method is highly recommended as, unlike dynamic analysis, it allows for the crucial inclusion of the nonlinear mechanical properties of the solder interconnects in computationally effective simulations.

Numerical Simulation of a Barge Impact on Bridges with Different Configurations of Pile Group Foundations

Three-dimensional finite element dynamic analyses were conducted to evaluate the effect of barge impact of different speeds on the lateral performance of three pile group (PG) configurations (vertical, battered, mixed) in terms of peak lateral displacement, peak shear force, lateral stiffness of PGs, and contribution of piles and pier columns to the total resisting force. The concrete material was modeled using the Concrete Damaged Plasticity model. The clay behavior was described using the Modified Cam Clay model; while the sand was modeled using the Drucker Prager model. The results showed that the vertical PG had the lowest lateral stiffness; while the battered and mixed PGs had closely larger stiffness, which allowed the development of larger impact force and pile cap displacement in vertical PG as compared to other PGs. The results of shear force showed that the foundation contributed up to 82% of the total lateral force in battered and mixed PGs. The results also showed that in vertical PG, the first row had slightly higher percentage of lateral force compared to other rows; while in battered PG, the load percentage was evenly distributed between rows. A contrast performance was observed for mixed PG. The results of bending moment (BM) showed that the piles in vertical PG had notably higher BM than the piles in other PGs due to larger pile cap displacement. In all PGs, the piles in the edge column had higher BM ratio, with the leading row (L) had the highest BM ratio (69–72%) in all PGs.

Design of a novel end-effector for robotic bud thinning of Agaricus bisporus mushrooms

Removing some of the overly dense buds of Agaricus bisporus in factory-cultivated mushroom beds through a process called bud thinning, as required by agronomy, can improve the top-grade product rate and yield and reduce the waste of production costs. At present, however, the only manual way to complete the bud thinning process is time-consuming and labor-intensive, which limits the development of the Agaricus bisporus industry. Robotic bud thinning is an optimal alternative to this issue. In this paper, firstly, a novel mechanized bud thinning mode is proposed based on the growth characteristics of bud emergence along with a dynamic finite element analysis of swing and lifting subprocesses to validate the separation mechanism. Secondly, a swing force and angle acquisition system is established to analyze the dynamic process by which the bud detaches from the substrate, followed by confirming the required swing force and angle of 0.96–2.81 N and 6.6–18.6°, respectively. Thirdly, a new end-effector for bud thinning is designed, including the steering, separation, and removal mechanisms. Furthermore, the airflow suction structure of the removal mechanism is improved via CFD analysis along with improved flow velocity and the magnitude of negative pressure, resulting in a removal success rate of 96.7 %. A robotic bud thinning test bench with the designed bud thinning end-effector was built, and the experimental results showed that the bud thinning end-effector offered a success rate of 91.7 % and an average single mushroom bud thinning time of 6.2 s, which shows the effectiveness and feasibility of this method. The designed end-effector has high potential for integration into a robot to support the bud thinning process of Agaricus bisporus in factory mushroom production.

Abstract 662: A Novel Approach To Understanding Geometric Remodeling Of Surgically Created Arteriovenous Fistulas

Objectives: Failure of arteriovenous fistulas (AVF) for dialysis access remains a persistent problem. The reason for failure is largely unknown. Computational models of AVF have not been validated in parallel with animal experiments. We propose a computational AVF model that predicts venous geometric remodeling. We hypothesize that remodeling may precede AVF failure. Methods: First, we use a validated murine AVF model to define the parameters and boundary conditions for our computational model. Anesthetized mice undergo laparotomy and aortocaval puncture. Ultrasound confirms AVF patency, flow velocities, and vessel geometry throughout the aorta and inferior vena cava (IVC). In vivo CT angiography scans are segmented using 3D software (Simpleware ScanIP) to establish global geometry. We use this geometry to build a simplified geometric model which is then imported into a fluid dynamics simulation (Xflow) and finite element analysis software (Abaqus). Findings: Segmentations of in vivo CT scans establish the global geometry of the AVF (Fig 1a). A fluid dynamics model replicates flow through the fistula (Fig 1b). The model depicts the wall pressure being highest in the artery and around the fistula connection. A computational dynamics model predicts deformation and venous remodeling after pressurization of the system (Fig 1c). Conclusions: This is the first in vivo-computational model of AVF geometry. Our results indicate elevated wall pressure at the level of the fistula leads to venous deformation as hypothesized. These results can be used to predict how the underlying anastomotic geometry may impact anastomotic stress, stenosis, and injury, and may help define anatomic parameters that could optimize AVF durability. Future experiments involving models using the in vivo geometry itself, higher resolution micro CT images, and histologic staining of the vessel wall will provide insight into the deformation mechanisms around these observed areas of remodeling.

Vibration Serviceability Evaluation of a Single Span Steel–Concrete Composite Foot Bridge under Dynamic Pedestrian Loadings Considering Moving Mass Effect

In this paper, we present the analysis results on the vibration serviceability of a pedestrian bridge considering the effect of pedestrian moving mass inertia. Using dynamic finite element analysis, we considered different walking scenarios, including pedestrian density, walking speed, random walking, and synchronized walking, to analyze the acceleration response of a 40m long single-span bridge with a steel composite box cross section. We showed that the equivalent fixed mass analysis method did not significantly differ from the moving mass analysis in the random walk scenario and a wider frequency excitation band may be useful to consider when evaluating vibration serviceability in a random walk scenario.

Analysis of a Steel Structure Considering Bracing System under Lateral Loading Condition Using Tekla Structures: A Review

The rapidly developing world, in construction industry software’s are used today is the urgent necessity of the moment in order to match the peace of infrastructural development. The main objective of the study is checking the computability of results. The analysis and design of Reinforced Concrete structures and steel structure is a final stage in the construction industry to deliver the projects within the estimated time and within the budget. Analysis and design tasks are not an easy matter of fact. Especially specialized software’s are used such as Robot structural Analysis, MIDAS Gen, SAP2000, STAAD PRO, ETABS, TEKLA Structural designer, S-Frame and so on. Key Word: Geometry, Structure, Analysis, Shear force, Storey Displacement, Deflection, Seismic analysis, Finite element analysis, Torsion, Static and Dynamic analysis.

Dynamic finite element analysis of hip replacement edge loading: Balancing precision and run time in a challenging model

An important aspect in evaluating the resilience of hip replacement designs is testing their performance under adverse conditions that cause edge loading of the acetabular liner. The representation of edge loading conditions in finite element models is computationally challenging due to the changing contact locations, need for fine meshes, and dynamic nature of the system.In this study, a combined mesh and mass-scaling sensitivity study was performed to identify an appropriate compromise between convergence and solution time of explicit finite element analysis in investigating edge loading in hip replacement devices. The optimised model was then used to conduct a sensitivity test investigating the effect of different hip simulator features (the mass of the translating fixture and mediolateral spring damping) on the plastic strain in the acetabular liner. Finally, the effect of multiple loading cycles on the progressive accumulation of plastic strain was then also examined using the optimised model.A modelling approach was developed which provides an effective compromise between mass-scaling effects and mesh refinement for a solution time per cycle of less than 1 h. This ‘Recommended Mesh’ model underestimated the plastic strains by less than 10%, compared to a ‘Best Estimate’ model with a run time of ∼190 h. Starting with this model setup would therefore significantly reduce any new model development time while also allowing the flexibility to incorporate additional complexities as required. The polyethylene liner plastic strain was found to be sensitive to the simulator mass and damping (doubling the mass or damping had a similar magnitude effect to doubling the swing phase load) and these should ideally be described in future experimental studies. The majority of the plastic strain (99%) accumulated within the first three load cycles.

PRE-CLINICAL TESTING AND FINITE ELEMENT SIMULATIONS OF ORTHOPAEDIC IMPACTION INSTRUMENTS USED IN SEATING OF IMPLANTS

Orthopaedic impaction-instruments are used to drive implants into the bone of the patient. Pre-clinical experimental testing protocols and computer models of those are used to assess robustness and functional efficiency of such instruments. This generally involves impaction of the instrument mounted on a substrate that should represent the mechanics of the patient. In this study, the effects of the substrate on stressing of the impaction-instruments were investigated using dynamic finite element analysis. Model results were compared with experimental data from lab protocols, which have been derived to recreate the mechanics of cadaveric implantations, which represent clinical conditions.FEA models of selected experimental protocols were created in which a simplified instrument was impacted on substrates with varying material properties and boundary conditions. After impaction, the instrument settled into a modal vibration which then decayed over time. The resulting axial strain data from the computational model was compared to strain-gauge data collected from experimental measurements. Strain signal amplitude, frequency and decay were compared. The damping-ratio was derived from the decay of the strain signal.The computational model slightly over-predicted the initial experimental strain amplitudes in all cases, but the frequency of the cyclic strain signals matched. However, the model underestimated the experimentally measured rate of signal decay. Inclusion of implant seating and soft-tissue conditions had little effect on decay.Clinical failures of impaction-instruments may be related to multiple fatigue cycles for each impaction and should be modelled accurately to allow failure prediction. Any soft substrate results in an impedance mismatch at the instrument interface, which reflects the pressure wave and causes vibration with a frequency related to the speed-of-sound in the instrument, and its geometry. While this could be accurately modelled computationally, signal decay was underestimated. Further experimental quantification of energy losses will be important to understand vibration decay.

Wind Turbine Blade-Tip Optimization: A Systemic Computational Approach

Curved bladelets on wind turbine blades play an important role in improving the performance and efficiency of wind turbines. Implementing such features on the tip of wind turbine blades can improve their overall aerodynamic characteristics by reducing turbulence and loading without hindering lift generation and overall efficiency, thus leading to increased energy capture and reduced costs over the life of the turbine. Subjecting the integrated blade tip to optimization procedures can maximize its beneficial contribution to the assembly in general. Within this context, a systemic workflow is proposed for the optimization of a curved bladelet implemented on a wind turbine blade. The approach receives input in the form of an initial tip geometry and performs improvements in two distinct stages. Firstly, shape optimization is performed directly on the outer shape to enhance its aerodynamic properties. Subsequently, the topology of its interior structure is refined to decrease its mass while retaining its improved airflow characteristics. The proposed workflow aims to approach blade tip optimization holistically, both in terms of aerodynamic performance and structural capabilities; is computationally validated via fluid dynamics studies and finite element analysis to evaluate the performance augmentation achieved through it; and is further coupled with additive manufacturing for the production of prototype parts, benefiting from the manufacturing flexibility offered by digital fabrication technologies. The optimized bladelet model presented an approximate 30% improvement in the torque generated on it, while maintaining only 70% of its original mass, effectively contributing to a 0.81% increase to the total torque generated by the blade, consequently confirming the effectiveness of the proposed methodology.

A CFD-FEA Method for Hydroelastic Analysis of Floating Structures

The so-called large multi-body floating offshore structure is a new type of offshore structure with a huge and extremely flat deck area, which has a promising prospect as a floating port and also in applications in the area of marine space exploitation. Due to its unique structural form, the hydrodynamic and structural response characteristics are very complex. Specifically, due to the instantaneous position variation in the body surface, the nonlinearity of the free surface, the interactions between floating bodies, and the elastic deformation of floating bodies, the nonlinear factors are significant and cannot be neglected. For these kinds of problems, methods based on CFD-FEA (computation fluid dynamics–finite element analysis) coupling simulation have significant advantages over traditional methods. In the present paper, the hydrodynamic and structural response characteristics of a large multi-body floating offshore structure are studied using a CFD-FEA method, and the results are compared with those obtained by the potential-flow-based commercial code SESAM/WADAM, and a three-dimensional nonlinear hydroelastic analysis commercial code COMPASS-WALCS-NE. The comparison and the analysis of the results show that the CFD-FEA method presented in this study can well simulate the behavior of the hydroelastic responses of flexible floating structures and has the potential to capture complex nonlinear behaviors.

Finite Element and Multibody Dynamics Analysis of a Ball Mill Glass Crusher

Recycling and sustainability constitute a major challenge to preserve human life quality and ensure a good standard of living for future generations. Like other recyclable waste products, glass waste can be a major problem if it is not recycled. When glass waste is turned into powder, environmental impacts are minimized by reducing or eliminating the dependency on landfills. Within this context, the objective of this work is to design a low-cost glass crusher machine that can be acquired by individuals. For this purpose, a glass crusher machine based on the ball mill concept is designed to transform glass waste into powder of 2 mm particle size. The main enhanced features of this machine with respect to state-of-the-art designs are the continuous feed aspect and the powder discharge technique. The design methodology consisted of mathematical modeling coupled with numerical simulations to ensure a safe and functioning design. This was achieved via different types of simulations using SolidWorks: static stress analysis, free vibration analysis, and motion study. Finally, a market study shows that a breakeven period is reached after a period of 5 months.

Seismic performance of mat-founded building clusters on liquefiable soils treated with ground densification

Current guidelines for evaluating the performance of ground densification as a liquefaction countermeasure near buildings are based on free-field conditions or, at best, consider one structure experiencing soil-structure interaction (SSI) in isolation. However, in urban areas, where structures are constructed in close vicinity of each other, structure-soil-structure interaction in liquefiable deposits near two (SSSI2) or multiple (≥3) buildings in a cluster (SSSI3+) has been shown as consequential on key engineering demand parameters (EDPs), particularly differential settlement. Furthermore, the potential tradeoffs associated with ground improvement in urban settings, considering SSSI2 and SSSI3+, are currently not well understood or defined. In this paper, three-dimensional (3D), fully-coupled, nonlinear, dynamic finite element analyses are first validated with centrifuge models of SSI and SSSI2, including ground densification. These models are subsequently used to explore the influence of building arrangement (two adjacent structures and four structures in a square block) and spacing on key EDPs for mitigated structures undergoing SSSI2 and SSSI3+ compared to that under isolated SSI. For the conditions evaluated, it is shown that both SSSI2 and SSSI3+ could reduce the average settlement of mitigated structures compared to SSI at building spacings (S) > 0.5Wfnd (where Wfnd is the foundation width), particularly in larger clusters experiencing SSSI3+. On the other hand, both SSSI2 and SSSI3+ amplified the permanent tilt of the mitigated structures compared to SSI at S < 0.5Wfnd. The impact of these interactions on tilt reduced at larger spacings. A limited, subsequent numerical sensitivity study showed that pulse-like input motions together with the stress and flow-path bias introduced by SSSI2 and SSSI3+ can increase the uneven accumulation of soil strains below the mitigated structures compared to cases experiencing SSI or the same building clusters subject to non-pulse-like motions. This led to a greater amplification in tilt of mitigated structures experiencing SSSI2 and SSSI3+ at shorter spacings under the selected pulse-like motions. Overall, the results point to the importance of considering the impact of building cluster arrangement, spacing, soil and structural properties, and ground motion characteristics in the design of ground improvement in urban settings.

Seismic response of concrete bridge of Lanzhou-Xinjiang high-speed railway under the near-fault strong earthquake

The MS6.9 earthquake in Menyuan, Qinghai, on January 8, 2022 caused severe damage to Sulphur Gully Bridge of Lanzhou-Xinjiang high-speed railway. In this paper, a two-dimensional numerical model of the structure and site soil is established with Sulphur Gully Bridge as the research object, and finite element dynamic time analysis is used to study the dynamic response characteristics of the box girder, pier, pile foundation and site of Sulphur Gully Bridge under ground motion loads. The results show that the peak acceleration in the pile and bridge superstructure system as a whole decreases linearly with height, the horizontal peak displacement of the bridge pile-superstructure system decreases linearly with height, and the peak displacement of the soil site as a whole gradually decays linearly as it is amplified farther from the bridge, and the horizontal peak displacement in the direction of the source is smaller than that of the site further away; the difference between the vertical peak displacement and the horizontal peak displacement is the difference between the vertical peak displacement and the horizontal peak displacement is about 5–13.6 times; the vertical peak displacement of the middle of the bridge pier and the pile changes very little as the height decreases, and the vertical peak displacement of the soil layer site as a whole gradually decays as the distance from the bridge is enlarged; the ground motion frequency of the bridge is mainly concentrated in 1–10 Hz, and the main frequency is distributed in 2 Hz, the peak Fourier spectrum of ground motion in the pile-superstructure system tends to decrease as the height decreases, and the peak Fourier spectrum of ground motion is the relationship is: box girder > abutment > soil site > pile; the relationship between the peak of ground motion energy spectrum of bridge is: pile > soil site > abutment > box girder.

Different Conical Angle Connection of Implant and Abutment Behavior: A Static and Dynamic Load Test and Finite Element Analysis Study.

Dental implants are artificial dental roots anchoring prosthetic restorations to replace natural teeth. Dental implant systems may have different tapered conical connections. Our research focused on the mechanical examination of implant-superstructure connections. Thirty-five samples with 5 different cone angles (24°, 35°, 55°, 75°, and 90°) were tested for static and dynamic loads, carried out by a mechanical fatigue testing machine. Fixing screws were fixed with a torque of 35 Ncm before measurements. For static loading, samples were loaded with a force of 500 N in 20 s. For dynamic loading, the samples were loaded for 15,000 cycles with a force of 250 ± 150 N. In both cases, the compression resulting from load and reverse torque was examined. At the highest compression load of the static tests, a significant difference (p = 0.021) was found for each cone angle group. Following dynamic loading, significant differences (p < 0.001) for the reverse torques of the fixing screw were also shown. Static and dynamic results showed a similar trend: under the same loading conditions, changing the cone angle-which determines the relationship between the implant and the abutment-had led to significant differences in the loosening of the fixing screw. In conclusion, the greater the angle of the implant-superstructure connection, the smaller the screw loosening due to loading, which may have considerable effects on the long-term, safe operation of the dental prosthesis.

Stochastic Dynamic Response and Long-Term Settlement Performance of Superstructure–Underground Tunnel–Soil Systems Subjected to Subway-Traffic Excitation

The vibration impact force from the long-term operation of a subway affects the comfort of the residents living above the superstructure and the long-term settlement deformation of the tunnel foundation. A method for evaluating the dynamic responses of superstructure–tunnel systems is important, especially because of the randomness of vibration impact force. The coupling effect of the randomness of train-vibration excitation and the nonlinearity of the geotechnical properties that are subjected to dynamic action leads to challenges in the evaluation of the performance of superstructure–underground tunnel–soil systems under train vibration. In this study, a stochastic dynamic model of subway vibration-load excitation was established; then, the time histories of samples with rich probability characteristics in the same set system were generated. According to the nonlinear dynamic finite element analysis, several nonlinear dynamic responses of the deterministic superstructure–tunnel soil-foundation system were obtained. Finally, the probabilistic performance evolution of the superstructure–tunnel soil-foundation system was obtained by integrating the first-passage and probability density evolution theories, and the long-term deformation performance of the tunnel foundation was evaluated using time-varying reliability. This study presents a novel probabilistic method and a more objective performance index for the dynamic performance assessment of superstructure–underground tunnel–soil systems that are subjected to subway-traffic excitation.

Wavenumber unwrapping for the automated analysis of SASW measurements

Depending upon the surface wave methods, the measured surface wave velocities are either normal mode velocities or apparent velocities. The “apparent” surface wave velocity corresponds to the superposed mode combining the available normal modes. The spectral-analysis-of-surface-waves (SASW) method measures the apparent surface wave velocities. However, these velocities render SASW analyses complicated because of the mode jumps induced by several wave groups. To alleviate such complications, this study introduced a beamforming technique and produced information on unwrapped wavenumber, which is vital in unwrapping the phase spectrum in SASW analyses. Additionally, incoming wave directions filtered out multiple reflections and irrelevant seismic events to retain only the surface waves directly propagating from the source. The proposed wavenumber unwrapping technique was verified using field applications, dynamic finite element analysis, and synthetic waveforms. Notably, an optimal beamforming technique was established using four geophones, making the proposed method highly practical and reducing the hardware requirements. Hopefully, the proposed analysis technique provides SASW practitioners with a more comfortable and more reliable environment in utilizing the SASW technique.

A simplified three-dimensional constitutive model for seismic modeling of dense sands

Dense sands subjected to earthquake shaking may not liquefy but experience differential settlements that can cause damage or limit the serviceability of overlying structures and utilities. Such settlements can be estimated using stress and/or strain based empirical models in conjunction with one-dimensional site response analyses utilizing normalized modulus reduction and damping curves and uni-directional ground shaking. Multi-directional effects are incorporated through applying additional factors. In contrast, there are limited number of studies on the three-dimensional (3-D) modeling of shear induced seismic response of sands. In this study, a simplified, mean stress-dependent constitutive model (termed I-soil) is presented for dense sands. The model adopts the framework of a class of multi-dimensional distributed-element models for cyclic plasticity applications. I-soil extends this framework for soil applications by adding non-Masing un/reloading rules and simplified shear induced volumetric response formulation. The shear response parameters can be calibrated using shear wave velocity, widely used normalized modulus reduction and damping curves. The shear induced volumetric response is calibrated using cyclic direct simple shear tests. Default values for model parameters and dynamic curves are proposed. The resulting model was implemented in a dynamic finite-element analysis platform, LS-DYNA. It is shown that simulations can capture the seismic shear and volumetric behavior of saturated sands measured under partially drained conditions in dynamic centrifuge tests.

The preliminary thermo–mechanical design, simulation and optimization, of LAD onboard the eXTP space mission

The eXTP (enhanced X-ray Timing and Polarimetry) mission is a major project of the Chinese Academy of Sciences (CAS) and China National Space Administration (CNSA) currently performing a phase B study and proposed for a launch in 2027. The eXTP scientific payload envisages a suite of instruments offering unprecedented simultaneous wide-band X-ray timing and polarimetry sensitivity. A large European consortium is contributing to the eXTP study and it is expected to provide key hardware elements, including the Large Area Detector (LAD) composed of 40 modules for a total effective area of 3.0 m2 at 6.0 keV. In this paper, we describe the preliminary study that led to the design solutions adopted for the most important thermo-mechanical drivers of the LAD Module, which have been elaborated and used for the demonstration of compliance to the system requirements at spacecraft level. We report in particular the mechanical design for the Module and its components, the thermal analysis for each range temperature of the worst cases (coldest case) with the evaluation of the thermoelastic deformation of a reduced module and the results of a campaign of static and dynamic finite element analysis of a simplified parametric model with an accurate mesh processing and the preliminary optimization of the critical components.