Methods In Structural Dynamics Research Articles

PSDM: A parametrized structural dynamic modeling method based on digital twin for performance prediction

Digital twin (DT) technology is a powerful tool that accurately represents physical entities and provides real-time monitoring and reliability analysis capabilities for decision-makers and managers. However, modeling complex systems in structural health monitoring using DTs can be repetitive and tedious with existing approaches. To address these issues, we propose a new approach called the Parametrized Structural Dynamic Modeling(PSDM) method. This approach effectively parametrizes dynamic systems in structural health monitoring by leveraging Proper Orthogonal Decomposition (POD) to represent and analyze complex structural behaviors. It also incorporates model reduction and kernel functions. By integrating physics-based insights and advanced modeling methodologies, the PSDM method aims to bridge the gap between the physical and digital domains, enabling accurate and efficient analysis of complex structural systems. To verify its accuracy and efficiency, we apply the PSDM method to two engineering cases: the wing cantilever beam and the telehandler boom. The results demonstrate that the online computational cost of the PSDM method is lower than Finite Element Methods (FEM), thereby improving the computational efficiency of DT modeling technology for complex-large structures. Thus, this research presents a feasible method for implementing structural reliability analysis for engineering equipment.

Calculation Method for Structural Dynamics of Material Ropeway under Startup and Shutdown Conditions with Single Concentrated Loads and Distributed Multiple Loads

In light of the unique structural features of material ropeway of transmission line, this paper presents a calculation method for the structural dynamics of material ropeway when subjected to single concentrated loads and distributed multiple loads. Taking into account the geometric nonlinearity and significant flexible deformation features of carrying rope and pulling rope in material ropeways, a finite mass point method is utilized for theoretical derivation to investigate the effects of varying load weights and speeds on tension fluctuations in carrying rope and pulling rope during the startup and shutdown processes. The results indicate that the proposed method can accurately calculate the tension and structural variations in carrying rope and pulling rope of multi-span material ropeway when subjected to single concentrated loads and distributed multiple loads. This method not only satisfies the requirements for transmission line engineering applications but also offers insights into the safe utilization of material ropeway of transmission line.

Comparative Study of Soft In-Plane and Stiff In-Plane Tiltrotor Blade Aerodynamics in Conversion Flight, Using CFD-CSD Coupling Approach

Tiltrotors permit aircrafts to operate vertically with lift, yet convert to ordinary forward flight with thrust. The challenge is to design a tiltrotor blade yielding maximum lift and thrust that converts smoothly without losing integrity or efficiency. The two types of blades, soft in-plane and stiff in-plane—the designation depending on the value of the blade’s natural lag frequency—exhibit different structural responses under the same flight conditions, differently affecting the aerodynamics of the blades, especially in the complex aerodynamic environment of conversion flight where the aerodynamic differences are significant. This phase of flight is not deeply researched, nor is the analytical coupling method much used. To study the influence of blade type on aerodynamics during conversion, models suitable for the conversion flight simulation are established for the application of coupled computational fluid dynamics and computational structural dynamics (CFD-CSD) methods. Each method is implemented with well-accepted techniques (the Unsteady Reynolds-Averaged Navier–Stokes (URANS) equations, the Reverse Overset Assembly Technique (ROAT), and the Timoshenko beam model. To improve the solving efficiency, a loose coupling strategy is used in constructing the two-way coupled model. The XV-15 tiltrotor is used for verification. The aeroelastic simulation of soft in-plane and stiff in-plane blades in conversion flight indicates an impactful role on the modal shapes, with a significant difference in the third flap modal shapes for the XV-15 rotor. However, the effect on aerodynamic performance is relatively small. In the first half of the flight conversion, the thrust of stiff in-plane blades is larger than that of soft in-plane blades, but in the last half, the influence of structural characteristics on aerodynamic performance is negligible and the thrust of the blades tends to be equal.

Aeroelastic reduced-order modeling for efficient static aeroelastic analysis considering geometric nonlinearity

The computational fluid dynamic/computational structural dynamic (CFD/CSD) coupling method plays an important role in static aeroelastic problems accounting for structural geometric nonlinearity. However, a huge computational burden comes from the CFD simulation, which also dominates the computational cost of the CFD/CSD coupling method. Therefore, this paper presents a reduced-order framework for steady aerodynamics to replace the CFD simulation, which is then coupled with the CSD solver for efficient static aeroelastic analysis considering geometric nonlinearity. Results first show that the proposed approach is capable of accurately predicting the surface pressure distribution of a high-aspect-ratio wing in its rigid undeformed shape at different Mach numbers and angles of attack, with at most a 2.5% relative error compared to CFD simulation. In addition, the geometrically nonlinear structure, a seminal benchmark without a tip slender body, is simulated by a three-dimensional open-source finite element solver coupled with either the CFD solver or the proposed reduced-order models (ROMs). The results demonstrate that the proposed ROM/CSD coupling approach can reflect the deformation and surface pressure distribution at static aeroelastic equilibrium with high accuracy and efficiency, thereby reducing the total computational cost at least five times while maintaining reasonable accuracy.

Structural Dynamics Analysis of ATPS Parachute using Nonlinear Finite Element method

A computational structural dynamics method based on the nonlinear finite element (NFE) model is developed for simulating the dynamic response of parachutes. Numerical simulation results for benchmark cases and ASTM parachute inflation demonstrate the advantages of the proposed method in terms of comparable accuracy, perfect convergence, superior algorithmic stability, and stronger ability to handle highly nonlinear equations. Compared with the existing numerical methods used in parachute simulation, the proposed method can capture the more real mechanical behaviour of parachute by introducing the nonlinear factors in the physical model involved into the governing equation entirely, then using the nonlinear theory to build the calculation model, last solving the equivalent linear equations.

Combination of Optimal Three-Step Composite Time Integration Method with Multi-Point Iterative Methods for Geometric Nonlinear Structural Dynamics

This study focuses on solving the geometric nonlinear dynamic equations of structures using the multi-point iterative methods within the optimal three-step composite time integration method (OTCTIM). The OTCTIM, initially devised for linear dynamic systems, is now proposed to encompass nonlinear dynamic systems in such a way that the semi-static nonlinear equations in time sub-steps can be solved using multi-point methods. The Weerakoon–Fernando method (WFM), Homeier method (HM), Jarrat method (JM), and Darvishi–Barati method (DBM) have been extended as multi-point solvers for nonlinear equations in OTCTIM, which exhibit a higher convergence order than the Newton–Raphson method (NRM), without requiring the calculation of second and higher derivatives. Several structural examples were solved to examine the performance of these methods in the OTCTIM approach. The results demonstrated that the multi-point iterative methods outperform NRM (in terms of the number of iterations) within the OTCTIM for geometric nonlinear structural dynamics and, among the multi-point methods, the JM and DBM converged with fewer number of iterations and lower error levels. Furthermore, it has been observed that when solving nonlinear dynamic equations for structures with a high number of degrees of freedom, the incorporation of the DBM into the OTCTIM mitigates the convergence iterations and the average elapsed time for iterative sub-steps.

Optimal implicit single-step time integration methods with equivalence to the second-order-type linear multistep methods for structural dynamics: Accuracy analysis based on an analytical framework

This paper presents a comprehensive study of the second-order-type time integration methods family encompassing the linear multistep (LMS) methods, the single-step methods, and the LMS equivalent single-step methods for structural dynamics. An analytical accuracy framework for algorithm design, convergence, and optimization is developed, where the obstacles encountered in algorithms construction, convergence accuracy, algorithms equivalence, accuracy measurement, and accuracy optimization in traditional accuracy frameworks are well addressed. Rigorous accuracy analysis successively to the second-order-type LMS (LMS2) methods, the single-step methods, and the LMS2 equivalent single-step methods aims to reveal optimal algorithms with desirable numerical properties. First, independent implicit algorithms including the velocity type and the acceleration type LMS2 methods except the displacement type ones are newly revealed in the LMS2 methods family with second-order convergence and A-stability, and three error constants that can play essential roles in the accuracy measurement and algorithm optimization are developed. Second, a single-step methods family where the displacement, velocity, and acceleration can achieve the same order of accuracy simultaneously is revealed in a generalized 16-parameters methods family, which contains numerous conventional single-step single-solve methods as subfamily methods. It is found that the unit consistent and non-consistent representations show a significant difference in the local truncation error, stability, and convergence performances. Third, a family of accuracy-improved single-step methods with algorithmic equivalence, which is stricter than the traditional spectral equivalence, to the LMS2 methods is revealed. It is clarified that the difference between the methods with equivalence can significantly influence their convergence accuracy, and the error constants concept of the LMS2 methods can be extended to the single-step method with algorithmic equivalence. Last, an algorithm optimization strategy is developed based on the error constants and the ultimate spectral radius, and an optimal single-step method with a single parameter to control the accuracy and numerical dissipation is revealed analytically without empirical assumptions. The optimal method is second-order accurate, unconditionally stable, overshooting acceptable, and equivalent to an optimal route between the Houbolt method and the trapezoidal rule, and its numerical performance is verified by the spectral accuracy and two numerical examples.

Fluid-induced vibration analysis of centrifugal pump including rotor system based on Computational Fluid Dynamics and Computational Structural Dynamics coupling approach

The flow-induced vibration of centrifugal pump under the effect of stator-rotor interaction are studied by Computational Fluid Dynamics method and Computational Structural Dynamics method based on the principle of one-way decomposition fluid-structure interaction. Firstly, the unsteady flow characteristics in centrifugal pump are studied by adopting the Computational Fluid Dynamics method, the numerical model of the whole flow field of the centrifugal pump is established, and the pulsating pressure characteristics of volute and impeller in the centrifugal pump are analyzed. The accuracy of the flow field modeling method and calculation method in this paper is verified by external characteristic test. Secondly, the vibration characteristic test of centrifugal pump is carried out, and the structural dynamic model and boundary conditions of centrifugal pump are verified and corrected in the modal test. Finally, the flow-induced excitation calculated by the flow field is simultaneously applied to the structural dynamics model of the centrifugal pump according to different transmission ways, and the flow-induced vibration of the whole centrifugal pump including the rotor system is calculated and analyzed by the Computational Structural Dynamics method in conjunction with rotor dynamics. Compared with the vibration test results, the validity of the flow-induced vibration calculation method of centrifugal pump in this paper is verified. The results show that under the influence of stator-rotor interaction effect, the blade passing frequency and shaft frequency are the main characteristic frequencies of pressure pulsation and dynamic response in the centrifugal pump.

Numerical simulation of seismically isolated buildings with friction pendulum bearings

Introduction. At present, in Tajikistan, buildings and structures are designed and constructed on the basis of passive methods of ensuring seismic resistance, which ultimately leads to an increase in stiffness and weight of structures and, accordingly, in seismic load. The present paper analyses seismic isolation of buildings provided by friction pendulum bearings. The dynamic model of the object under study is represented as a system consisting of a superstructure, substructure and seismic isolation.Aim. To contribute to the development of methods for analysis and evaluation of seismic isolation and earthquake protection of buildings and structures in order to justify the conditions for their effective application in earthquake-resistant construction on the territory of the Republic of Tajikistan.Materials and methods. The authors used methods of structural mechanics, structural dynamics, and numerical simulation. The research methodology involves mathematical modeling of the systems under consideration, numerical analysis, comparison of the obtained results with the available data. Experimental investigation was carried out on a building fragment model and a vibration platform.Results. The authors developed a mathematical model for investigating the stress-strain state of a building with friction pendulum bearings subjected to various external influences, including seismic ones. The differential equation system using successive approximations is transformed into a system of algebraic equations, which is solved at each time step. On the basis of the created algorithm, the authors developed a computer program in Fortran and obtained the numerical results of the dynamic calculation for a multistory building with friction pendulum bearings. The results from the action of an instantaneous impulse are obtained on the example of a 10-story frame building.Conclusions. The results show that the application of seismic isolation in the form of friction pendulum bearings leads to a significant reduction of internal forces in the support part, as well as to a reduction of velocity and acceleration in the upper part of the building compared to the model without seismic isolation bearings. At the same time, the deflections of both the lower and upper parts of the investigated object slightly increase.

Dynamic characteristics and response analysis of a new type of prefabricated fly ash foam concrete structure

Traditional structural dynamics methods for calculating the natural vibration period and mode shape of a structure are not ideal for structures with high natural frequencies. In particular, when buildings are subjected to seismic waves of predominant periods, they will resonate and cause more severe damage. This phenomenon disregards the effect of damping on a structure. The major parameter that considers energy dissipation in structures is the damping ratio. However, no good method for directly calculating the damping ratio is currently available. To address this issue, this study proposes a calculation method for natural vibration period and mode (damping method) that considers damping. It calculates the structural damping ratio by using an energy method and then applies structural dynamics and ABAQUS to verify the results. Finally, ABAQUS is used to study the dynamic response of the new prefabricated fly ash foam concrete structure under the action of two natural waves, and one artificial wave at different fortification intensities. The results show that the influence of damping on the natural vibration period and shape value of the structure is within 9.0%. The damping ratio of this structure is 0.059. The maximum interlayer displacement of the structure under the action of bidirectional seismic waves is 25.3 mm. The maximum interlayer displacement angle is 1/493, the torsional displacement ratio is 1.28, and the minimum interlayer shear force is 609 kN. All the calculation results meet the design requirements of “no collapse under strong earthquakes.”

Stochastic spectral cell method for structural dynamics and wave propagations

AbstractThe spectral element method when enriched with the concept of fictitious domain constitutes the spectral cell method which is appropriately able to model geometrically complicated problems by simplifying the mesh generation. In this paper, we propose a new computational framework called stochastic spectral cell method (SSCM) as a stochastic development of the spectral cell method for uncertainty quantification applied to structural dynamics and wave propagations. The stochastic form of spectral cell method has not been developed yet. Hence, the SSCM is a novel stochastic method comprising the advantages of spectral cell method for computational mechanics considering the geometrical complexity resulting from computer‐aided design. The SSCM is established by incorporating the polynomial chaos and Karhunen‐Loève expansions for the uncertainty quantification, and the interpolation functions of spectral elements for the spatial discretization. In the SSCM, the numerical solution of the Fredholm integral equation of the second kind required in Karhunen‐Loève expansion is obtained using the spectral cell method. The use of Cartesian mesh, diagonal mass matrix, and higher order interpolation functions of spectral elements for stochastic dynamic analysis lead to desirable computational efficiency and accuracy of the SSCM. The capability, effectiveness, and accuracy of the proposed SSCM are demonstrated with several numerical examples of wave propagation as well as dynamic analysis of structures.

A generalized elastic coordinate method for unconstrained structural dynamics

A generalized elastic coordinate method (GECM) is proposed for the vibrational (elastic) response analysis of unconstrained structural dynamics. Firstly, the generalized rigid body and elastic coordinates are defined to describe the overall motion of a discrete unconstrained structure. Secondly, the corresponding equations of motion for generalized elastic coordinates are established with a tiny computational cost, and the stiffness matrix is still sparse. Finally, the elastic deformation in physical space can be exactly caught by the proposed equations of motion after determining the rigid body modes and the coordinate system of the rigid body motion. Different from directly solving the original semi-positive definite system in physical space, in which the overall displacement can only obtain, and the direct modal projection, the modal truncation error problem can be effectively overcome based on the established positive definite system when the modal order reduction is carried out. In light of this, the modal truncation error correction of the elastic displacement for the transient time domain and steady-state frequency domain of unconstrained structures is directly realized, summed the above as GECM, and the validity and practicability are illustrated through the numerical examples.

THE MODEL OF ASSESSMENT OF GOODS EXPORTS OF UKRAINE TO THE WORLD INTEGRATION ASSOCIATIONS

Foreign trade is an important factor of economic growth and development of open economies. At the same time, the analysis of the state of foreign trade operations is becoming methodologically more complex due to the increase in the number of indicators used and the appearance of new ones. They allow not only to examine the effectiveness of the state trade policy, the set of goods and trade partners, but also to get an idea of the structure of the economy, the level of its development and competitiveness, as well as to assess the quality of the export and import baskets from the point of view of economic growth prospects. Therefore, it is advisable to use models of commodity export valuation, which determines the relevance of the chosen topic. The subject of the study is the methods and models of commodity export evaluation. The purpose of the article is the formation of a model for the evaluation of Ukraine's commodity exports to the integration associations of the world and its approval. Methodology. The theoretical and methodological basis of the conducted research is the dialectical method of cognition, the principles of system analysis and synthesis, statistical processing of information. The methods of structural dynamics were used for the analysis of statistical indicators of commodity exports for 2016-2020; the method of constant market share – for the evaluation of changes in commodity exports of Ukraine for the period under consideration; the method of scientific abstraction is used for the generalization of the obtained results and the formation of conclusions; the graphic method – for the visual presentation of the obtained research results. Results. The article proposes a model for assessing Ukraine's commodity exports to the world integration associations, the main component of which is the constant market share method (CMS analysis). This model is easy to use and allows a qualitative assessment of changes in Ukraine's commodity exports. Approval of the model and assessment of changes in commodity exports of Ukraine was carried out on the international statistical database UNCTADstat for 2016-2020. The data are aggregated into groups according to the Standard International Trade Classification (SITC). The following trading partners have been selected for the CMS analysis: EU-27, ASEAN+3, CIS and REST OF THE WORLD. The obtained results make it possible to assess the state of Ukraine's commodity exports and the level of its competitiveness in foreign markets. Practical implications. The practical implications are related to the possibility of using the proposed model for the evaluation of commodity exports, using various options for the classification of goods and integration associations – partners of the exporting country. Value / originality. The originality lies in the development of a model for the assessment of Ukraine's commodity exports to the world integration associations based on the Constant Market Share (CMS) method, which allows to determine to what extent exports change with the growth of the competitiveness of the goods of the exporting country.

Geometrically Nonlinear Flutter Analysis Based on CFD/CSD Methods and Wind Tunnel Experimental Verification

This study presents a high-speed geometrically nonlinear flutter analysis calculation method based on the high-precision computational fluid dynamics/computational structural dynamics methods. In the proposed method, the aerodynamic simulation was conducted based on computational fluid dynamics, and the structural model was established using the nonlinear finite element model and tangential stiffness matrix. First, the equilibrium position was obtained using the nonlinear static aeroelastic iteration. Second, the structural modal under a steady aerodynamic load was extracted. Finally, the generalized displacement time curve was obtained by coupling the unsteady aerodynamics and linearized structure motion equations. Moreover, if the flutter is not at a critical state, the incoming flow dynamic pressure needs to be changed, and the above steps must be repeated until the vibration amplitude are equal. Furthermore, the high-speed geometrically nonlinear flutter of the wing-body assembly model with a high-aspect ratio was investigated, and the correctness of the method was verified using high-speed wind tunnel experiments. The results showed that the geometric nonlinearity of the large deformation of the wing caused in-plane bending to become a key factor in flutter characteristics and significantly decreased the dynamic pressure and frequency of the nonlinear flutter compared to those of the linear flutter.

Towards a Unified Single Analysis Framework Embedded with Multiple Spatial and Time Discretized Methods for Linear Structural Dynamics

We propose a novel computational framework that is capable of employing different time integration algorithms and different space discretized methods such as the Finite Element Method, particle methods, and other spatial methods on a single body sub-divided into multiple subdomains. This is in conjunction with implementing the well known Generalized Single Step Single Solve (GS4) family of algorithms which encompass the entire scope of Linear Multistep algorithms that have been developed over the past 50 years or so and are second order accurate into the Differential Algebraic Equation framework. In the current state of technology, the coupling of altogether different time integration algorithms has been limited to the same family of algorithms such as the Newmark methods and the coupling of different algorithms usually has resulted in reduced accuracy in one or more variables including the Lagrange multiplier. However, the robustness and versatility of the GS4 with its ability to accurately account for the numerical shifts in various time schemes it encompasses, overcomes such barriers and allows a wide variety of arbitrary implicit-implicit, implicit-explicit, and explicit-explicit pairing of the various time schemes while maintaining the second order accuracy in time for not only all primary variables such as displacement, velocity and acceleration but also the Lagrange multipliers used for coupling the subdomains. By selecting an appropriate spatial method and time scheme on the area with localized phenomena contrary to utilizing a single process on the entire body, the proposed work has the potential to better capture the physics of a given simulation. The method is validated by solving 2D problems for the linear second order systems with various combination of spatial methods and time schemes with great flexibility. The accuracy and efficacy of the present work have not yet been seen in the current field, and it has shown significant promise in its capabilities and effectiveness for general linear dynamics through numerical examples.

Retraction Note: An Implicit Unconditionally Stable Integration Method for Nonlinear Structural Dynamics and Earthquake Engineering Problems

Retraction Note: An Implicit Unconditionally Stable Integration Method for Nonlinear Structural Dynamics and Earthquake Engineering Problems

An harmonic equivalent excitation method for random vibration response

Many loads on engineering structures had obvious randomness, such as earthquakes, wind, sea waves, uneven pavement, etc. The calculation and analysis of random vibration were complicated and inefficient, which has perplexed the development of engineering technology for a long time. To solve the above problems, this paper proposed a harmonic equivalent excitation method for structural random vibration analysis. The excitation force of multi-frequency action in continuous time interval was converted into harmonic excitation force with the same effect as superposition excitation in each discrete time interval by a harmonic equivalent method. The frequency and amplitude of harmonic excitation force in discrete-time intervals were calculated, which were then taken as the deterministic load input of the structure. The response of the structure was calculated by the conventional structural dynamic analysis method. Finally, the harmonic equivalent excitation method was used to analyze random pavement excitation and its application in the control of time-delay vibration reduction. The results show that the harmonic equivalent excitation method simplifies the calculation form of random vibration analysis without reducing the accuracy, and provides an effective method for analyzing random vibration in the engineering field.

RETRACTED ARTICLE: An Implicit Unconditionally Stable Integration Method for Nonlinear Structural Dynamics and Earthquake Engineering Problems

A novel time integration procedure is designed in order to solve the differential equation of motion of dynamics and earthquake engineering problems. The procedure is constituted on the principle of impulse-momentum, leading to a lesser number of assumed fields. The algorithmic properties of the procedure are determined by stability and accuracy analyses. Overshooting tendency, which is not related to stability and accuracy characteristic of a method, and order of accuracy are also examined. It is displayed that the new method is unconditionally stable and non-dissipative. Also, the numerical dispersion of the proposed algorithm appears to be much less than the commonly used integration methods. The method has no tendency to overshoot both the displacement and velocity response solutions. Its order of accuracy is around four as compared to two of the other methods considered in the study. A few numerical examples consisting of both single and multi-degree of freedom systems with linear and nonlinear characteristics are performed to see the overall behavior of the method in various practical problems. The numerical results of the proposed method obtained from these examples coincide well with the simulated exact results.

Aerodynamic shape optimization using a time spectral coupled adjoint for nonlinear aeroelastic problems

In this work, prediction of flutter and Limit Cycle Oscillations (LCO) for the aircraft wing has been carried out using a coupled, time spectral computational fluid dynamics (CFD) and computational structural dynamics (CSD) method. Flutter related shape design has also been carried out using a coupled, adjoint based sensitivity analysis framework. A discrete adjoint solver was developed in time-spectral form to calculate coupled sensitivity of the dynamic aeroelastic motion. The total structural energy was constrained at different levels to determine the flutter onset conditions or different LCO solutions. Compared to the time-marching approach, the time-spectral method not only enables faster convergence for unsteady problems, but also leads to significant improvement in implementation of adjoint based sensitivity analysis. Unlike the time-marching approach, there is no high memory requirement for time-spectral approach. The proposed method was applied to a pitch-plunge airfoil section at transonic flight conditions. The flutter and LCO results showed great agreements with time-marching results. The adjoint based sensitivity values were validated by finite difference based results, showing great agreement with errors less than 2%. Finally, aerodynamic shape optimization was carried out with the design objective of maximizing the flutter velocity, with and without constraint on the drag coefficient, respectively. Significant increase in flutter boundary velocity was observed in both cases.

Toward Simulation of Fe(II) Low-Spin → High-Spin Photoswitching by Synergistic Spin-Vibronic Dynamics.

A new theoretical approach is presented and applied for the simulation of Fe(II) low-spin (LS, singlet, t2g6eg0) → high-spin (HS, quintet, t2g4eg2) photoswitching dynamics of the octahedral model complex [Fe(NCH)6]2+. The utilized synergistic methodology heavily exploits the strengths of complementary electronic structure and spin-vibronic dynamics methods. Specifically, we perform 3D quantum dynamics (QD) and full-dimensional trajectory surface hopping (TSH, in conjunction with a linear vibronic coupling model), with the modes for QD selected by TSH. We follow a hybrid approach which is based on the application of time-dependent density functional theory (TD-DFT) excited-state potential energy surfaces (PESs) and multiconfigurational second-order perturbation theory (CASPT2) spin–orbit couplings (SOCs). Our method delivers accurate singlet–triplet–quintet intersystem crossing (ISC) dynamics, as assessed by comparison to our recent high-level ab initio simulations and related time-resolved experimental data. Furthermore, we investigate the capability of our simulations to identify the location of ISCs. Finally, we assess the approximation of constant SOCs (calculated at the Franck–Condon geometry), whose validity has central importance for the combination of TD-DFT PESs and CASPT2 SOCs. This efficient methodology will have a key role in simulating LS → HS dynamics for more complicated cases, involving higher density of states and varying electronic character, as well as the analysis of ultrafast experiments.