Transient Temperature Conditions Research Articles

Characterization of thermoelectric generator modules: Numerical and analytical study on heat flow determination under transient temperature conditions

Characterization of thermoelectric generator modules: Numerical and analytical study on heat flow determination under transient temperature conditions

Elucidating the role of Cr migration in Ni-Cr exposed to molten FLiNaK via multiscale characterization

Structural materials used in nuclear reactor environments are subjected to coupled extremes such as high temperature, irradiation, and corrosion which act in concert to degrade their functional performance. Connecting alloy microstructure such as grain boundaries, and accumulating point defects with corrosion attack and pore morphology is critical to understanding underlying mechanisms. We uncover the compositional variations and morphology at multiple length scales in corrosion-damaged Ni-Cr alloy after exposure to oxidants in molten fluoride salts. A complex network of dense corrosion pores is detected by surface-level SEM observations. The corrosion pores take on a 1-dimensional morphology and are enriched with Ni and depleted of Cr 1–5 µm from the pore surface. STEM-EDS and 4D-STEM strain maps acquired simultaneously highlight the local variations in composition and structure of a ≤ 200 nm Cr-rich layer identified from a cross-section taken at the bottom of an isolated corrosion pore between the Ni-Cr alloy matrix and the embedded salt. However, the absence of an observed interface between the Ni-Cr alloy matrix and the FCC-structured Cr-rich layer suggests that Cr plating from the salt did not transpire. These findings support a proposed Cr lattice diffusion mechanism rather than Cr-precipitation from the salt to accommodate temperature transient conditions during sample cooling. Through the development of a 1D phase field model, these results are rationalized by formation energies for the Ni- and Cr-oxidation into the molten salt. This study reveals the locally altered microstructure caused by high temperature corrosion in non-steady-state molten salt nuclear reactor environments.

Thermal analysis of 4-phase 8/6 SRM for EV application

This article provides a comprehensive analysis of the thermal characteristics of a 4-phase 8/6 switching reluctance motor (SRM) designed for use in an e-rickshaw (3-wheeler) application. The determination of core and copper losses is achieved through electromagnetic analysis using Finite Element Analysis (FEA). The analysis is conducted via MOTORCAD, a multiphysics design software. This work includes the examination of both static and transient temperature conditions. Static analysis entails the estimation of losses by taking into account the motor's maximum current and operating the motor under steady-state conditions. Transient analysis involves the examination of two separate scenarios. One possesses a simple transient characteristic, while the other possesses a distinct duty cycle. The losses obtained from the electromagnetic analysis are used as the input for the simple transient thermal analysis. During transient analysis involving the duty cycle, losses are assigned to certain operating conditions, such as changes in the operating speed of the motor. This study employs the Lumped Parameter Thermal Network (LPTN), as well as 3D and 2D FEA techniques to conduct thermal analysis. The findings were compared and subsequently given in the article. The findings produced from the LPTN and 3D FEA approaches demonstrate a strong correlation. The motor's maximum temperature is limited to 180 °C. The findings indicate that the highest temperature, both under static and transient conditions, is below the maximum attainable value.

Effect of temperature on tribofilm growth and the lubrication of the piston ring-cylinder liner system in two-stroke marine engines

This study is an optimized extension based on the authors’ previous research on the tribo-chemical reaction under constant temperature field of two-stroke internal combustion engines (ICEs). It establishes a coupled analysis model that considers the tribo-chemical reactions, dynamic contact, and interface lubrication of the piston ring-cylinder liner (PRCL) system under transient temperature conditions. In this study, for the first time, the prediction of the tribofilm thickness and its influence on the surface micro-topography (the comprehensive roughness) are coupled in the working temperature field of the PRCL system, forming an effective model framework and providing a model basis and analytical basis for subsequent research. This study findings reveal that by incorporating temperature and tribofilm into the simulation model, the average friction deviation throughout the stroke decreases from 8.92% to 0.93% when compared to experimental results. Moreover, the deviation during the combustion regime reduces from 39.56% to 7.34%. The proposed coupled model provides a valuable tool for the evaluation of lubrication performance of the PRCL system and supports the analysis software forward design in two-stroke ICEs.

Experimental and Numerical Simulation of Effects of High Temperature on RC Frame Infilled with Sandwich Panel

This study investigated the structural behavior of reinforced concrete (RC) frames infilled with masonry walls and polyurethane (PU) sandwich wall panels at elevated temperatures. This study aims to assess the influence of temperature on the stiffness and load-carrying capacity of infilled frames, optimize the thickness of the sandwich wall panel, and compare the performance of masonry and sandwich infill systems. Analytical investigations were conducted using finite element analysis software (ABAQUS) to simulate the behavior of the frames at elevated temperatures and consider various configurations of skin thickness for PU sandwich panels. Experimental tests were performed to validate the analytical results. The frames were subjected to transient temperature conditions and uniform unit loads to evaluate their response. Experimental tests were conducted on RC frames infilled with masonry and sandwich-wall panels at elevated temperatures. The frames were subjected to static loading, and their deformations and failure modes were observed. The analytical study revealed that an increase in the skin thickness of the sandwich panel improved its temperature resistance, stress-withstanding ability, and displacement. A skin thickness of 0.45 mm was determined to be the optimal choice considering stress levels and economic factors. The infilled frame with the sandwich wall panel exhibited a 19.22% higher initial stiffness than the masonry wall panel in the experimental tests. The ultimate load-carrying capacity decreased by 17.86% in the infilled sandwich wall panel frame compared to the masonry infill system. The study provides valuable insights into the behavior of RC frames infilled with masonry walls and sandwich wall panels under elevated temperatures. The optimized thickness of the PU sandwich panel was determined by balancing the thermal resistance and the structural performance. The infilled frames with sandwich wall panels exhibited enhanced stiffness but slightly reduced ultimate load-carrying capacity compared with the masonry infill. These findings contribute to the understanding of thermal effects on building structures and can aid in the design and construction of more resilient and efficient buildings in the future. Doi: 10.28991/CEJ-2024-010-01-018 Full Text: PDF

Empirical and mechanistic transient fission gas release model for high-burnup LOCA conditions

In response to the nuclear industry desire to extend burnup beyond current licensing practices, the US Nuclear Regulatory Commission (NRC) released a research information letter (RIL) that provides a basis for analyzing fuel fragmentation, relocation, and dispersal (FFRD) in light-water reactors. Of the five elements discussed, the most ambiguous is the significance of transient fission gas (FG) release (FGR) (tFGR) and its effects on fuel performance under loss-of-coolant accident conditions. In fresh fuel, FG migration and eventual release is primarily governed by diffusion-based mechanisms at higher temperatures (>1,000 °C). However, the mechanisms governing FGR changes as burnup increases. More recent research indicates that FGR increases as burnup increases, specifically under temperature transient conditions, and this release occurs at lower temperatures with a new release mechanism. This behavior has been attributed to microcracking in the fuel and is likely related to microstructure embrittlement with the presence of over pressurized FG bubbles. The NRC RIL outlines the complexity of the phenomenon and a need for a deeper understanding to adequately address FFRD for regulatory application. Therefore, this manuscript intends to summarize the publicly available tFGR data and discuss the observed dependencies (e.g., burnup, heating rate, sample geometry, terminal temperature). An empirical model has been developed and benchmarked against recently published experimental data. However, this empirical model is limited to conditions for which fitting data exist and, therefore, a high-level discussion is included to provide a roadmap for atomistically-informed multiscale modeling in conjunction with experimental data collection to develop a mechanistic tFGR model widely applicable to a broad range of nuclear fuel conditions at high burnup.

Temperature-based thermo-electric coupling maximum power point tracking algorithm for thermoelectric generation systems under transient conditions

The applications of thermoelectric generators (TEGs) are expanding from stable to complex environments. Traditional maximum power point tracking (MPPT) algorithms observe the electrical characteristics of TEG, and make judgments based on historical data. In a system with transient temperature conditions, the influence of system temperature on the electrical characteristics of TEG becomes the main effect, which confuses traditional algorithms and causes misjudgment. To address this issue, this paper proposes a temperature-based thermo-electric coupling MPPT (TTEC-MPPT) algorithm that considers temperature information during TEG operation. The algorithm uses Lagrange Interpolation Polynomial to predict the temperature difference of TEG and divides the disturbance step into two parts based on the temperature and algorithm. Experimental results show that the proposed algorithm outperforms four traditional algorithms and three sets of fixed pulse width modulation (PWM) conditions in five different cases, with an average power increase of 11.9211% and 20.1128% compared to traditional algorithms and fixed PWM respectively in transient cases. By considering the effect of temperature, the TTEC-MPPT algorithm has an advantage in dealing with complex transient temperature conditions compared to existing algorithms.

Development and verification of the mathematical modeling for gas-pressurizer system

The accurate simulation of the dynamic characteristics of a pressure control system (Pressurizer) has a significant role in industrial applications, especially in the nuclear industry. In this paper, the pressurizer (PRZ) used in the water process engineering and nuclear reactors are classified into three categories: Steam PRZ, Steam-gas PRZ, and Gas PRZ. Nowadays, steam PRZs are typically used in pressurized nuclear reactors. In return, due to the proper characteristics of gas PRZ, these systems are expected to be a suitable alternative for use in Small Modular Reactors (SMRs) and even other pressurized research reactors. However, there is a lack of literature about the context of the gas PRZ. As one of the works about gas PRZ, this paper suggests a mathematical model to predict the gas PRZ’s dynamic behavior and implements this framework in MATLAB software. This proposed model's performance has been evaluated and verified for two pressurized water test facilities, including the University of Wisconsin High-Pressure Critical Heat Flux (WHPCHF) facility and the Idaho National Laboratory (INL) facility as the base loops. Throughout this analysis, the suggested model performance during the temperature and pressure transient conditions are compared with the results of the PRZ modeled in the Aspen HYSYS software for both base loops. Also, the diagrams of PRZ mass inventory changes, liquid level inside the PRZ and pressure in both different test loops with different non-condensable gases (nitrogen and argon) show that the proposed mathematical model is in good agreement with the results by Aspen HYSYS. Therefore, this proposed mathematical model can suitably model the dynamic behavior of a gas PRZ. The proposed model can also be used to simulate gas PRZs control systems and the extension in studying about the modeling of these PRZs.

FEM Study of a Steel Corrugated Web Plate Girder Subjected to Fire

The main aim of this work is a computational nonlinear analysis of a high strength steel corrugated-web plate girder with a very detailed and realistic mesh including vertical ribs, all the fillet welds and supporting areas. The analysis is carried out to verify mechanical structural response under transient fire temperature conditions accounting for an efficiency and accuracy of three various transient coupled thermo-elastic models. All the resulting stress distributions, deformation modes and their time variations, critical loads and eigenfrequencies as well as failure times are compared in all these models. Nonlinearities include material, geometrical and contact phenomena up to the temperature fluctuations together with temperature-dependent constitutive relations for high strength steel. They result partially from steady state and transient experimental tests or from the additional designing rules included in Eurocodes. A fire scenario includes an application of the normative fire gas temperature curve on the bottom flange of the entire girder for a period of 180 minutes. It is computed using sequentially coupled thermo-elastic Finite Element Method analyses. These account for heat conductivity, radiation and convection. The FEM model consists of a combination of 3D hexahedral and tetrahedral solid finite elements and uses temperature-dependent material and physical parameters, whose values are taken after the experiments presented in Eurocodes. Numerical results presented here demonstrate a fundamental role of the lower flange in carrying fire loads according to this scenario and show a contribution of the ribs and of the welds to the strength of the entire structure.

A Critical Review of High Burnup Fuel Fragmentation, Relocation, and Dispersal under Loss-Of-Coolant Accident Conditions

High burnup fuel in excess of ~6268 GWd/MTU has been observed to severely fragment when subjected to temperature transient conditions as in a loss-of-coolant accident. In the event of cladding failure, the severely fragmented fuel can relocate into the balloon region and potentially disperse through the burst opening into the reactor’s primary system. This observation has led to implementation of several independent test programs designed to focus on various aspects of fuel fragmentation, relocation, and dispersal. The purpose of this review is to perform a critical, holistic assessment of fuel fragmentation, relocation, and dispersal under loss-of-coolant conditions to identify data gaps in the experimental data base. Phenomena have been identified and well defined through the various testing programs, and general agreement regarding the governing parameters (temperature, burnup, heating rate, cladding deformation, etc.) has been established. However, there is a significant data gap connecting research to commercial application. Furthermore, previous research attempted to evaluate the problem holistically, but has yet to provide a comprehensive understanding of the problem. Major identified data gaps consist of (1) a comprehensive understanding of pretransient fuel rod conditions (fuel temperature, fuel stress, rod internal pressures, microstructure, etc.), (2) definition of prototypic loss-of-coolant accident conditions (heating rate, fuel temperatures, fuel stress), (3) identification of the differences between nuclear and electrical integral loss-of-coolant accident tests, and connection of fuel rod performance (cladding ballooning, burst opening, potential relocation, fragmentation susceptibility, etc.) to fuel fragmentation, relocation, and dispersal severity. The content of this manuscript provides a clear path for connecting testing and data acquisition to commercial application by providing concrete means for filling data gaps and prioritized testing regimes.

Large anisotropic negative thermal expansion in Cu-TDPAT metal-organic framework: A combined in situ X-ray diffraction and DRIFTS study

Cu-TDPAT (H6TDPAT = 2,4,6-tris(3,5-dicarboxylphenylamino)-1,3,5-triazine), a stable nanoporous metal-organic framework with rht topology, has sparked broad interest as an adsorbent for several chemical separation processes. In this work, in situ synchrotron diffraction experiments followed by sequential LeBail refinements reveal that Cu-TDPAT shows unusually large anisotropic negative thermal expansion (NTE). The PASCal crystallography tool, used to analyze the magnitude of the NTE, reveals an average volumetric thermal expansion coefficient αv = −20.3 MK−1. This value is significantly higher than the one reported for Cu-BTC (also known as HKUST-1), which contains the same Cu-paddlewheel building unit, αv ≈ −12 MK−1. In situ synchrotron single crystal X-ray diffraction and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) were employed to shed light on the NTE mechanism. Using these two methods, we were able to elucidate the three main structural motions that are responsible for the NTE effect. The more pronounced NTE behavior of Cu-TDPAT is attributed to the lower symmetry combined with the more complex ligand structure when compared to Cu-BTC. The knowledge obtained in this work is important for understanding the behavior of the adsorbent under transient variable temperature conditions in fixed adsorption beds.

Elevated temperature characteristics of steel reinforcement incorporating threaded mechanical couplers

This paper presents an experimental study into the influence of elevated temperatures on the mechanical properties of hot-rolled steel reinforcement which is spliced using two alternative types of threaded couplers. The investigation includes tests performed under steady-state and transient elevated temperature conditions for reinforcement bars of 16 mm and 20 mm diameter. For comparison purposes, tests carried out under ambient conditions and for non-spliced reinforcement bars are also included in the study. After describing the experimental arrangement and instrumentation, including purpose-adapted digital image correlation techniques, a detailed account of the test results is given. In addition to offering a direct evaluation of the temperature-dependent stiffness and strength properties, the test results provide an assessment of the complete stress-strain response. The strain hardening and ductility properties are also determined as a function of temperature for both spliced and non-spliced specimens. It is shown that the presence of couplers typically influences the ductility characteristics of threaded splices at elevated temperature as a function of the type and geometry of the couplers, whilst the stiffness and strength properties are largely similar to those of their non-spliced counterparts. The performance characteristics obtained from the detailed test measurements are used within the discussions to highlight issues relevant for application in practice.

Modeling creep of steel under transient temperature conditions of fire

This paper presents a methodology for explicit modeling of the time-dependent behavior or creep of structural steel in the Abaqus finite element (FE) models under transient temperature conditions representative of building fires. In this methodology, available creep models based on conventional creep tests under constant or steady-state temperature conditions were used to predict the time-dependent or creep behavior of steel under variable or transient-state temperature conditions. Specifically, user-defined CREEP subroutines were created in Abaqus to define time-dependent or viscoplastic deformation of structural steel under changing temperatures. To demonstrate the robustness of the proposed methodology, the time-dependent behavior of structural steel at elevated temperatures was modeled under three distinct conditions. These were: steady-state temperature conditions, stepwise steady-state temperature conditions, and transient-state temperature conditions. This paper further presents and discusses the application of the methodology in studying the creep behavior of a shear tab connection assembly under the transient temperature conditions of a fire. Through this application, the importance of explicit consideration of creep in predicting the response of connection assemblies at different stages in the evolution of a structural-fire is also emphasized.

Mechanical properties of GFRP reinforcing bars at high temperatures

This paper presents experimental results of tensile strength tests on glass fibre reinforced polymer (GFRP) bars at high temperatures. These results are a part of a comprehensive study on characteristics of GFRP reinforcing bars from different manufacturers. To represent real construction practices, commonly used #5 GFRP reinforcing bars with nominal diameter of 16 mm are studied. The reinforcing bars are selected from three different manufacturers to study the potential differences of various products. Besides conventional steady-state temperature testing, tensile tests are conducted under transient temperature conditions. In transient tests, specimens are loaded before heat exposure. Temperature ranges from 25 to 500 °C are considered for the steady-state tests depending on the type of bar, and for the transient temperature tests, bars are loaded to between 25 and 70% of the bar’s strength at room temperature. The overall conclusion relating to fire performance of GFRP reinforced concrete members is that the three types of GFRP bars that are tested can retain the expected service stress level of 25% of their original tensile strength up to at least 400 °C, and this temperature can be used as the critical temperature in design.

Buildings with environmental quality management, part 2: Integration of hydronic heating/cooling with thermal mass

The quest for a sustainable built environment brought dramatic changes to architectural design because of the integrated design process. The integrated design process is the modern way to realize “performance architecture,” that is, design with a view to field performance. Integrated design process permits merging of concepts from passive-house designs, solar engineering, and an integration of the building enclosure with mechanical services. In part 1 of this series, the emergence of many new multi-functional materials was discussed. Yet, current innovation is guided by lessons from history. Thermal mass in heavy masonry buildings allowed periodic heating. The authors postulate integration of a hydronic heating system with the walls and the use of smart temperature control of the heating system to modify and optimize the thermal mass contribution. To use the mass of a building, one must accept transient temperature conditions where the indoor temperature varies but is confined by comfort requirements for both summer and winter conditions. On the other side, resiliency requirements dictate that in the absence of electricity the air temperature does not fall below about 12°C over a period of several hours. This requirement implies that summer cooling will likely be separated from the heating systems and that operation of a low-energy building is heavily dependent on the design of smart control systems. Analysis of control systems provided in this article for earth-to-air heat exchangers and cooling of houses with lightweight walls lead us to the requirements of separation between heating and ventilation and needs for different sources of fresh air. Finally, a new concept emerges.

Numerical calculation and experimental verification of the fictitious angular velocity for transient temperature impact on the fiber-optic gyroscope coil

Numerical simulation and experimental investigation of the effect of two types of quadrupole winding of fiber coil on the fictitious angular velocity of a fiber-optic gyroscope under transient temperature conditions are carried out. The coil is formed by winding optical fiber precovered with two protective-hardening layers on the cylindrical surface and its further fixation by compound. For experimental verification of the fictitious angular velocity, a special device was made, in which the fiber coil was held by rubber gaskets used to maximally exclude the transfer of mechanical loads from the body parts to the coil. A functional for the fictitious angular velocity is represented as a function of temperature and elastic strain rate in the fiber core. In the software ANSYS, a two-dimensional axisymmetric finite-element analog of a structurally inhomogeneous coil in the device is modeled. To verify the elastic strains under uniform thermal actions, the problem of stationary thermoelasticity was solved. With the Brillouin optical time domain analyizer, Brillouin frequencies shifts at two temperatures were established, and the distribution of strains was obtained. A comparison of the calculated and experimental strains made it possible to refine the Poisson's ratio of a weakly compressible primary coating. The solution of the transient thermal problem and temperature sensor readings allowed us to establish the heat-conductivity coefficient between the device and the moving air in the heat chamber. As an impact, we considered the heating of the environment at a rate of 1 °C/min, followed by a steady-state output. To find the temperature and strain fields for the functional of fictitious angular velocity, the unbound quasistationary thermoelasticity problem was solved. Tests were carried out with two types of winding of the coil. The experimental results showed satisfactory agreement with the calculated data.

Impact of acoustic forcing on soot evolution and temperature in ethylene-air flames

This combined numerical and experimental study assesses the transient coupling of soot formation, flame chemistry and fluid transport in ethylene-air coflow flames at acoustic forcing frequencies of 20 and 40 Hz. The measurements report soot volume fraction and flow velocity. For the computational analysis, the numerical code’s capability in modeling soot formation is first demonstrated in a steady coflow flame. Soot volume fraction and temperature measurements from different laboratories and optical techniques are used for validation. Then, acoustic forcing is applied to investigate the transient behavior of this multi-dimensional combustion problem. Forcing at different frequencies and amplitudes provokes very distinct transient soot, temperature, and flow conditions. The discussed steady ethylene-air flame is excited with 20 and 40 Hz, corresponding to Strouhal numbers of 0.23 and 0.46. For both frequencies, forcing amplitudes of 20, 50, and 60% are studied numerically and validated against measurements at 50%. With a start-up transient analysis, the computation time to reach a periodic state is evaluated and soot volume fraction predictions are then compared with the measurements. A reduction in maximum soot volume fraction for the increased forcing frequency is observed experimentally and numerically. The decrease in maximum soot volume fraction is explained by a residence time analysis revealing shorter maximum fluid parcel residence times for the 40 Hz than for the 20 Hz case. It is also found that at 40 Hz the transient evolution of maximum soot production and forced fuel velocity is almost synchronized, while for the 20 Hz case, a time lag of 32.5 ms is observed, corresponding to 65% of a full period.

The effect of oxidation-and-quenching process during a LOCA on the behavior of the oxidation and embrittlement of Zircaloy-4 cladding under reheating transients

ABSTRACTTwo-sided oxidation tests, ring compression tests and semi-integral quench tests on Zircaloy-4 cladding specimens were conducted under temperature transient conditions simulating a post-quench reheat transient in order to evaluate the effect of high-temperature oxidation and quenching during a loss-of-coolant accident (LOCA) on the behavior of the oxidation and embrittlement of the cladding under a loss of long-term core-cooling condition. Test specimens prepared from non-irradiated Zircaloy-4 cladding tube were oxidized at a temperature between 1173 and 1473 K in steam flow and quenched by soaking the specimen in room temperature water. Re-heating tests were performed on the specimens in steam flow at a temperature between 1173 and 1473 K. The suppression of oxide layer growth and weight gain was observed under certain reheating-after-quenching conditions. Nevertheless, it seemed that the temperature transients including quenching-and-reheating process did not significantly affect the embrittlement of cladding. It was found that the embrittlement behavior of cladding during the temperature transients including quenching-and-reheating process could be dealt with on the basis of the Equivalent Cladding Reacted (ECR) based on the Baker–Just correlation.

Unsteady-state human-body exergy consumption rate and its relation to subjective assessment of dynamic thermal environments

Few examples studied applicability of exergy analysis on human thermal comfort. These examples relate the human-body exergy consumption rate with subjectively obtained thermal sensation votes and had been based on steady-state calculation methods. However, humans are rarely exposed to steady-state thermal environments. Therefore, the first objective of the current paper was to compare a recently introduced unsteady-state model with previously used steady-state model using data obtained under both constant and transient temperature conditions. The second objective was to explore a relationship between the human-body exergy consumption rate and subjective assessment of thermal environment represented by thermal sensation as well as to extend the investigation towards thermal acceptability votes. Comparison of steady-state and unsteady-state model showed that results from both models were comparable when applied to data from environments with constant operative temperature. In contrast, when applied to data with temperature transients the prediction of particular models differed significantly and the unsteady-state model resulted in better prediction of mean skin temperature. The results of the present study confirmed previously indicated trends that lowest human body exergy consumption rate is associated with thermal sensation close to neutrality. Moreover, higher acceptability was in general associated with lower human body exergy consumption rate.

Thermomechanical Properties and Shape‐Memory Behavior of Bisphenol A Diacrylate‐Based Shape‐Memory Polymers

A series of acrylate‐based shape‐memory materials are synthesized from bisphenol A diacrylate monomers as crosslinking agents. Networks are synthesized by keeping constant the content of bisphenol A‐based crosslinking agent and systematically varying the content ratio of different monofunctional chain builder monomers. The implications of the structure of bisphenol A‐based monomers and the chemical structure and content of monofunctional monomers on thermomechanical properties are discussed. Thermomechanical properties are analyzed using dynamic mechanical analyses and mechanical properties are studied at room temperature and at the onset of the glass transition temperature. Shape‐memory performances under isothermal and transient temperature conditions are also carried out. Tensile tests show excellent values of stress at break up to 45 and 15 MPa at room and high temperature, respectively. The measurements show excellent shape recovery and shape fixity ratios, ≈95% and 97%, respectively. These materials also show very high recovery velocities under transient temperature conditions, up to 24% min−1, and very short recovery times, up to 1.5 s, under isothermal conditions in a water bath. The results confirm that networks synthesized from bisphenol A crosslinkers are promising shape‐memory materials.image