Stiffness Distribution Research Articles

Seismic vulnerability analysis of irregular and regular structures using fragility curve

The demand for innovative and visually appealing building designs according to specific desires or needs has led to many structures being built with irregularities. High-rise buildings with structural irregularities are at a higher risk of collapse during an earthquake if they are not designed and constructed properly according to existing regulations. Some buildings have non-uniform floor heights, which can lead to uneven distribution of stiffness throughout the structure vertically. Excessive height of one floor compared to the floor above it can potentially create an excessive soft story. Evaluating and assessing seismic vulnerability of structures is a major issue in earthquake-resistant design. This study discusses an analytical model for developing fragility curves by evaluating the seismic performance of a structure. The objective of this research is to determine and compare the estimated fragility levels of structures subjected to seismic loads between irregular structures with soft story irregularities and regular structures. Based on the results and discussion, it can be concluded that irregular structures (with soft story irregularities) have higher fragility levels compared to regular structures in both the x and y directions.

A Numerical Approach to Predict the Flexural Response of Simply Supported Nonhomogeneous and Non-Slender Graded Beams

In recent years, one promising avenue to optimize material design is the development of functionally graded materials (FGMs), which represent a new generation of composites with tailored mechanical properties. These properties vary continuously according to a function-law, allowing FGMs to mitigate issues like interfacial debonding and stress concentration. Accordingly, this study focuses on simulating the mechanical behavior of simply supported FGM non-slender beams under bending using finite element modeling (FEM). The numerical procedure and the loading setup as well as the implementation the power-law function which governs the stiffness distribution of the used metal and ceramic materials are explicitly presented. In addition, an optimal mesh size is determined for the modeled FGM beams. The numerical results show the effect of material exponent index and beam span ration on displacements and stresses distributions. The validated FEM-tool developed in this work provides a reliable means for estimating the elastic flexural response of non-slender graded beams under bending.

Comparative 3D finite element analysis of intramedullary fixation versus locking plate fixation in calcaneal fractures using micro-CT image technology

ObjectiveCalcaneal fracture fixation remains a challenging procedure in orthopedics, with computational tools increasingly aiding in the optimization of preoperative planning. To compare the biomechanical stability of intramedullary fixation and locking plate fixation for Sanders II and III calcaneal fractures by three-dimensional (3D) finite element analysis and to provide a theoretical basis for clinical application.MethodsThe Computed Tomography (CT) images were segmented using Mimics software (Materialise NV, Belgium) to identify the region of interest based on threshold segmentation. The 3D morphology was reconstructed using Mimics 10.01 software. Subsequently, Geomagic2012 software (3D Systems, USA) was employed to remove noise points, sharp corners, and scattered points, achieving a smooth surface map. This map was saved in Initial Graphics Exchange Specification (IGES) format and imported into Solidworks (Dassault Systèmes, France) for model assembly and volume model construction. A three-dimensional finite element model of Sanders II/III, calcaneal fractures with intramedullary fixation and locking plate fixation, was established and analyzed by linear finite element analysis. The forced displacement, stiffness, and stress distribution of the two fixation methods were calculated. In addition, the three-dimensional model was tested using a compression mechanical experiment.ResultsComparing fixation methods for Sander II and III fractures, the force-displacement curve of the intramedullary nail group aligned more closely with standards. Under axial compression, bone stress was highest with the Sanders II locking plate and lowest with the intramedullary nail. Across models, the intramedullary nail consistently exhibited slightly higher stress than the locking plate. The intramedullary nailing group model of the overall stiffness was slightly greater than the locking plate. By comparing the compressive mechanical test performance of the two fixation methods, it was found that the plate fixation group had an abnormal load until 7092.895 N, which was 1.5 times more than the load of the intramedullary nail.ConclusionBoth intramedullary fixation and locking plate fixation for Sanders II and III calcaneal fractures have certain biomechanical stability, and locking plate fixation has potential application value in clinical practice.

Haptiknit: Distributed stiffness knitting for wearable haptics.

Haptic devices typically rely on rigid actuators and bulky power supply systems, limiting wearability. Soft materials improve comfort, but careful distribution of stiffness is required to ground actuation forces and enable load transfer to the skin. We present Haptiknit, an approach in which soft, wearable, knit textiles with embedded pneumatic actuators enable programmable haptic display. By integrating pneumatic actuators within high- and low-stiffness machine-knit layers, each actuator can transmit 40 newtons in force with a bandwidth of 14.5 hertz. We demonstrate the concept with an adjustable sleeve for the forearm coupled to an untethered pneumatic control system that conveys a diverse array of social touch signals. We assessed the sleeve's performance for discriminative and affective touch in a three-part user study and compared our results with those of prior electromagnetically actuated approaches. Haptiknit improves touch localization compared with vibrotactile stimulation and communicates social touch cues with fewer actuators than pneumatic textiles that do not invoke distributed stiffness. The Haptiknit sleeve resulted in similar recognition of social touch gestures compared to a voice-coil array but represented a more portable and comfortable form factor.

Design and analysis of one-pad gas foil bearing with three-part gas film produced by adjusting the length of sliding beams

The one-pad sliding-beam gas foil bearing is studied in this paper. The size of the multiple sliding beams in the bearing is adjusted, which results in dividing the gas film pressure into three parts. The finite element mesh of the bottom foil is established based on rectangle and triangle elements, and the finite element model of sliding beams is established based on the plate element with five degrees of freedom. The separation and friction of the foils are considered, and the model of the foils is established based on minimum potential energy theorem and Newton–Raphson method. The mechanical model of the bearing is finally established by fluid-solid interaction. The calculation scheme is programmed by MATLAB, and the reliability of the model is verified by experiments. The numerical results show that with the increase of preload or the decrease of nominal clearance, the gas film pressure is divided into three parts gradually. Compared with the three-pad structure, the bearing in this paper has better bearing capacity. With nominal clearance being 30 µm, the maximum bearing capacity is obtained with a preload of 10 µm, and the maximum direct damping is obtained with a preload of 20 µm. A proper layout of sliding beams can improve the bearing capacity, but it could also weaken the dynamic performance. The variation of the initial bending stiffness distribution of sliding beams has little impact on the dynamic performance, but it can significantly affect the bearing capacity. When the stiffness of sliding beams of axial middle face is larger than that of the end face, the bearing capacity is obviously improved.

Study on the parameters of steel plate reinforcement rib-deck crack considering local stress disturbances

Local reinforcement will change the local stiffness distribution of the component, causing perturbation effects on the local stress of the fatigue detail. Only considering the reinforcement effect may lead to excessive strengthening and induce new fatigue-prone points. For the fatigue detail of the rib-deck weld, steel plate reinforcement test and numerical simulations were conducted. The stress changes of the deck weld toe and weld root before and after reinforcement were analyzed. The influence of parameters such as steel plate length, thickness, and width on the reinforcement effect of the weld toe crack and local stress disturbance was discussed, and reasonable parameters were recommended. The results show that after the cracking of the weld toe, the stress concentration locations at the weld toe and weld root of the deck shift from the center of the specimen to the crack tip. Steel plate reinforcement can effectively restrain the crack propagation, but can lead to an increase in the stress at the deck weld root within the reinforced area. A good reinforcement effect can be achieved while the steel plate covers the crack, and further increasing the steel plate length has limited improvement on the reinforcement effect but reduces the adverse effect of steel plate reinforcement on the stress of the deck weld root. Increasing the steel plate width will increase the adverse effect of steel plate reinforcement on the deck weld root stress, and it is recommended to use steel plates with a length greater than 120 mm and a length-to-width ratio greater than 4 for reinforcement. Increasing the width of the steel plate has a relatively small effect on the reinforcement effect and the stress at the deck weld root, and steel plates with the same thickness as the deck are recommended.

On the Finite Element Modeling of Metal/Ceramic Functionally Graded Beams Subjected to Non-Uniform Static Bending

Currently, several approaches focused on the optimization of materials design and solutions to respond to the ecological and economic concerns through the development of novel materials and structures. In this connection, functionally graded materials (FGM) known as a new generation of composites with optimized mechanical properties which vary according to a continuous function-law to avoid interfacial debonding and stresses concentration were largely investigated. Accordingly, the main purpose of this work is to advocate a new way to simulate the mechanical behavior of simply supported FGM beams submitted to non-uniform static bending through a finite element modeling (FEM). The power-law function which governs the stiffness distribution of the used metal and ceramic materials are explicitly presented. In addition, a mesh sensitivity was established to assess the optimal mesh size of the modeled FGM based-beams. The simulation outcomes presented in the form stress and strain cartographies were correlated with a good agreement to the analytical results from the literature in term of qualitative and quantitative validations.

Optomagnetic Micromirror Arrays for Mapping Large Area Stiffness Distributions of Biomimetic Materials.

A new device termed "Optomagnetic Micromirror Arrays" (OMA) is demonstrated capable of mapping the stiffness distribution of biomimetic materials across a 5.1 mm × 7.2 mm field of view with cellular resolution. The OMA device comprises an array of 50000 magnetic micromirrors with optical grating structures embedded beneath an elastic PDMS film, with biomimetic materials affixed on top. Illumination of a broadband white light beam onto these micromirrors results in the reflection of microscale rainbow light rays on each micromirror. When a magnetic field is applied, it causes each micromirror to tilt differently depending on the local stiffness of the biomimetic materials. Through imaging these micromirrors with low N.A. optics, a specific narrow band of reflection light rays from each micromirror is captured. Changing a micromirror's tilt angle also alters the color spectrum it reflects back to the imaging system and the color of the micromirror image it represents. As a result, OMA can infer the local stiffness of the biomimetic materials through the color change detected on each micromirror. OMA offers the potential for high-throughput stiffness mapping at the tissue-level while maintaining spatial resolution at the cellular level.

A non-classical computational method for modelling functionally graded porous planar media using micropolar theory

The current study proposes a computational-based method to employ the non-classical micropolar continuum for modelling plates with in-plane functionally graded porosities. Initially, a homogenisation method is developed to derive the micropolar parameters of porous heterogenous plates based on strain energy equivalence in various designed deformations simulated via finite element analysis. The modelling procedure is further augmented to accommodate structures with functionally graded porosities. The established method offers an effective framework for studying the mechanical behaviour of porous plates with various porosity distributions and a wide range of aspect ratios. Results indicate that the micropolar theory-based modelling surpasses traditional Cauchy theory in accurately predicting the stiffness and displacement distribution of the FG porous structures. The novelty of this study lies in the integration of micropolar theory with the homogenisation of graded porosity patterns, offering enhanced predictions for materials with microstructural features. Additionally, a custom finite element formulation is developed in COMSOL to implement micropolar elasticity, significantly improving the computational efficiency to account for complex geometry, loading, and boundary conditions. To show the applicability of the method, the modelling is used to design a dental implant with its functional property mimicking that of the natural bone to avoid stress-shielding while ensuring proper occlusivity.

Application value of strain elastography in testicular injury assessment after torsion.

To evaluate the capability of strain elastography (SE) in assessing the degree of testicular injury after torsion. In total, 50 rabbits were divided into four groups according to different degrees of testicular torsion (TT) at 0°, 180°, 360°, and 720°. For each animal, according to the tissue stiffness distribution, an SE score and strain ratio (SR) were obtained. With the histopathological results as the reference, the correlation coefficients of the apoptotic index and SE score or SR were calculated, and the receiver operating characteristic (ROC) curves were created to assess the capability of SE in assessing the degree of testicular injury. A significant positive correlation was found between the apoptotic index and SE score, as well as the SR, with corresponding correlation coefficients of 0.70 (<0.001) and 0.68 (P = 0.001), respectively. The areas under the ROC curves (AUCs) of the SE score and SR for identifying ischemia/hypoxia injury were found to be 0.81 (95% CI, 0.71-0.93) and 0.73 (95% CI, 0.60-0.86), respectively. For identifying irreversible damage, the AUCs were 0.69 (95% CI, 0.56-0.83) and 0.71 (95% CI, 0.59-0.84) for the SE score and SR, respectively. SE scores exhibited good diagnostic capability for detecting ischemia/hypoxia injury after TT. In early identification of severe injury/necrosis following TT, SE demonstrated some value but was not ideal.

A new concept reduced scale aeroelastic model of the four-cable suspension bridge with truss girder and its validation

The accuracy of the aeroelastic model or truss girders has consistently been a decisive factor influencing the results of full-bridge aeroelastic wind tunnel tests. A novel design approach, termed the Multi-Spine Frame System, is introduced for the reduced-scale model of the stiffening girder. This system incorporates multiple spines, thinner beams and columns to minimize aerodynamic interference while accurately simulating overall stiffness, mass, and constraints. The design procedure is formulated as an optimization problem with the objective of optimizing the low-order natural frequencies (lateral bending, vertical bending, and torsion) of the aeroelastic model. Pattern search method and penalty functions are employed to identify a locally optimal solution that satisfies engineering applications for this optimization problem. This design method is applied to an actual project involving a four-cable suspension bridge with a truss girder, and the test results demonstrate the accuracy of this approach in simulating the dynamic characteristics of the aeroelastic model. Corresponding wind tunnel tests on flutter instability, as well as numerical multi-modal flutter analysis, are conducted to analyze the critical flutter speed, vibration shapes, and frequencies of this bridge. Furthermore, the impact of deviation in structural mode shapes and natural frequencies on flutter instability is investigated using ten design schemes achieved by altering boundary conditions, mass distributions, and stiffness distributions, were examined. Significant differences in critical flutter speed (up to 9%) are observed due to deviations in mode shapes, emphasizing the necessity of considering modal frequencies and other modal information, such as mode shapes, in aeroelastic model design. This approach contributes to the advancement of aeroelastic model design for bridges with truss girders by introducing an effective system and an optimization method, providing a basis for future studies on wind instability and structural dynamics and also underscores the importance of accurate mode shape representation in flutter analysis.

Assessment of Hoisting Conveyance Guiding Forces Based on Field Acceleration Measurements and Numerical Simulation

Shafts play a key role in the operation of mining plants. They connect underground excavations with the surface and provide the ability to transport people, equipment, and raw materials. The nature of the dynamic interaction of a conveyance moving at a significant speed along deformed guide rails is complex, and the method of assessing the interaction of hoisting conveyances with shaft steelwork, despite ongoing research, still requires further understanding and improvement. Misalignments of the guide rails and conveyance movements transverse to the shaft axis induce impact (guiding) forces, which are the key design parameters of shaft steelwork. The reliable assessment of guiding forces allows the design of safe and economical steelworks and the assessment of their structural safety during operation under deformations and corrosive deterioration. Determining the value of guiding forces requires their field measurements or the use of approximate empirical formulas. Both methods have their limitations—measurement is expensive and interferes with normal shaft operation, while empirical formulas are subject to high error due to the lack of consideration of many structural details specific to each shaft that significantly affect the behavior of the system. This study presents a new method for using a relatively simple-to-implement measurement of hoisting conveyance acceleration to assess guiding forces. A finite element model of the skip and steelwork was built, and simulations of the conveyance interaction with the structure were carried out. A strong relationship between the sliding plate’s impact point location and the guiding force was found. Extreme values of the guiding force were observed in the vicinity of the bunton connection. The study showed that reducing the skip load mass does not affect the force value. Simplified methods of calculating the moments of inertia of the hoisting conveyance significantly overestimate the code-based values of the guiding forces. The presented method considers the actual stiffness and mass distribution of hoisting conveyance and, therefore, allows for a more accurate estimation of the guiding forces and the transport of larger loads. This data-driven approach allows for the continuous monitoring of the guiding forces, the adjustments of the hoisting parameters, the rational planning of repairs, and a reduction in the replacement of corroded shaft steelwork.

Modal modification based analysis of seismic performance of the Jiufeng Temple Ancient Masonry Pagoda

Based on detailed data collected on-site, including structural construction, cross-sectional dimensions, and material properties, this paper establishes a refined three-dimensional solid initial numerical model (INM) of the Jiufeng Temple Ancient Masonry Pagoda using the ABAQUS finite element software. On the basis of the measured modal characteristics (frequency, vibration mode, and damping ratio) of the ancient masonry pagoda, a modified numerical model (MNM) was obtained by adjusting the key parameters (damping ratio, Rayleigh damping coefficients, elastic modulus, and material density) of the initial numerical model. Based on the modified numerical model, five actual strong earthquake records were input to calculate the seismic response of the ancient masonry pagoda. The seismic failure mechanism of the ancient masonry pagoda, as well as the distribution characteristics of the principal tensile stress and seismic weak-layers were analyzed. The results indicate that the stiffness and mass distribution of the ancient masonry pagoda are consistent along its height, and the deformation at the top of the ancient masonry pagoda is significant under seismic action. The results obtained from the initial numerical model are more conservative, with the maximum storey drift being 19 %, 40 %, and 27 % larger than those of the modified numerical model under minor earthquakes (with a 63 % probability of exceedance in 50 years, also called frequently occurring earthquakes), moderate earthquakes (with a 10 % probability of exceedance in 50 years), and major earthquakes (with a 2 % probability of exceedance in 50 years, also called rarely occurring earthquakes), respectively. Under the action of major earthquakes, the upper portion of the Jiufeng Temple ancient masonry Pagoda, particularly above the 9th floor, may suffer severe damage. The 10th, 11th, and 12th floors are identified as the weak-layers of the ancient masonry pagoda, and the weak-layers determination from the modified numerical model are consistent with the results of standard calculations. The method proposed in this paper can provide technical support for the seismic protection of ancient masonry pagodas.

Stiffness increase and homogenization by coupled robots

This article presents the explanation of higher than expected increase of stiffness of coupled robots in some geometric configurations against its expected simple addition. This phenomenon was named the vault principle for robots. In order to achieve that and to explore fully the consequences it was necessary to develop a new method for robot stiffness analysis. Single serial robot is compared with two serial robots mutually connected. Connected (coupled) robots are analyzed in five various topological configurations. The end effector stiffness field is evaluated at particular points of intersections of workspaces of five topological configurations in order to preserve the objectivity of the comparison. The new method for robot stiffness analysis is based on the evaluation of minimum/maximum values of principal axes of stiffness distribution determined by the singular value decomposition. The manimum/maximum values across the workspace are processed by average/median and used for computing homogeneity factor. It is a new integral criterion for robot topology configuration judgment. The direct implications of these findings are relevant to high-precision milling applications in cooperative robotic setups.

The investigation of nonlinear dynamic characteristics of spur gear with angular misalignment error based on an improved dynamic model

Angular misalignment error is a prevalent occurrence in gear systems, mainly caused by manufacturing and installation errors in gearbox components. This significantly impacts the meshing characteristics of the system, making it necessary to carry out the nonlinear dynamic analysis of spur gear pairs with angular misalignment errors. In this study, a meshing stiffness model for a spur gear pair with angular misalignment error is established based on the Load Teeth Contact Analysis (LTCA) method. The effect of misalignment errors on the distribution of tooth surface stiffness are analyzed. Additionally, an improved dynamic model considering angular misalignment errors and variable backlash along the tooth width direction was proposed based on the lumped mass method and the slicing method. The effects of angular misalignment errors parallel and perpendicular to the meshing plane on the nonlinear dynamics of the system were studied. Frequency domain diagrams, Poincaré diagrams, and bifurcation diagrams were employed to comprehensively analyze the nonlinear characteristics of the system. The results indicate that with light loads, the system experiences a sequence of periodic and chaotic motions as θa increases, eventually returning to periodic motion. Conversely, θv shows minimal influence on the gear backlash, with the system exhibiting periodic motion when θv is small. As θv increases, the system transitions to chaotic motion before ultimately returning to periodic motion. Under heavy load conditions, as θa increases, the system transitions gradually from chaotic to periodic motion. However, regardless of the variations in θv, the system consistently remains in periodic motion.

Characterizing machine tool spatial stiffness and predicting accuracy

As a typical precision machine, the machine tool has complex structure and changeable working conditions, which leads to huge calculation data and low analysis efficiency when using traditional finite element method to obtain stiffness information. General test methods often have discrete values and cannot obtain stiffness information comprehensively and systematically. In this paper, a method for characterizing the stiffness of machine tool processing space based on multi-body system topology is proposed. Based on the matrix condensation theory, a method for constructing the equivalent condensation model of the stiffness of machine tool components is proposed. The stiffness characterization model of the components is established by using the stiffness equivalent condensation method. Based on the multi-body system theory, the stiffness distribution model of machine tool machining space is established, which can quickly and intuitively characterize the machining stiffness information of machine tool. Finally, based on the stiffness distribution model of the machining space of the machine tool, the machining accuracy of the S-shaped test specimen is predicted. Combined with the experimental analysis, the measurement results are consistent with the prediction results. The accuracy, feasibility, and effectiveness of the stiffness distribution model of machine tool machining space are verified.

A Comparative Study on Seismic Behaviour of Plan Irregular Buildings

Abstract: Asymmetrical plan irregularities occur when the horizontal layout of a building is non uniform or unsymmetrical in one or more axes. These irregularities may arise from variations in building shape, size, or configuration, leading to nonuniform distribution of mass, stiffness, or load paths throughout the structure. Considering equivalent static analysis (ESA) and response spectrum analysis (RSA) as per IS 1893-Part 1 (2016) considering seismic zones III, structure with square shaped plan performs better than the other shaped models (viz. T, L, H and Plus shapes) with least values of storey displacement and storey drift ratio, and also with higher value of storey stiffness. Thus, square plan shaped structure is seismically more resistant than T, L, H and Plus shaped structures.

Proportional distribution pattern and modal principle of tuned viscous mass dampers for multi-degree-of-freedom structures

A tuned viscous mass damper (TVMD) is an inerter-based damper that has been adopted in several high-rise buildings in earthquake-prone Japan recently to protect the structures from seismic-induced vibrations. However, as a TVMD contains a mass element, it adds degrees of freedom to the controlled structure, making the system’s eigenmodes complex. Inspired by the Rayleigh damping matrix, this study proposes a mass-proportionally distributed TVMD (MPD-TVMD) system, which enhances the efficiency of TVMD utilization compared to the previously proposed stiffness-proportionally distributed TVMD (SPD-TVMD) system. It is theoretically proven in this study that when the arrangements of the TVMDs are proportional to the stiffness or mass distribution of the primary structure, the equations of motion of a TVMD controlled shear building can be decomposed into the eigenmodes of the uncontrolled structure. This modal principle allows structural engineers to estimate the response of the controlled structure by understanding the modal characteristics of the uncontrolled system, which is highly beneficial for preliminary design decisions and the retrofitting of existing structures. Furthermore, given that the damping properties at each story level are typically adjusted by the number of dampers installed, it is often unrealistic in practical design to maintain strict proportionality in damper distribution. Through numerical examples, this study demonstrates that TVMD systems with realistic distribution patterns that are slightly different from a strictly proportional distribution can still perform as effectively as strictly proportional systems, providing a comprehensive design basis for the application of inerter-based damper in practical engineering.

Fabrication of a flexible inner prosthetic socket via the FGM technique

Purpose The purpose of this study was to fabricate a flexible inner socket with enhanced stiffness and hardness distribution by using the functional gradient method (FGM). The FGM technique can improve the comfort and flexibility of amputees through the use of a socket that is built via the direct method. Design/methodology/approach Six flexible inner socket samples were fabricated with varying weight fractions of rice husk ash-to-silicone rubber. The tensile strength and hardness of each sample were assessed. Then, numerical analyses were conducted using SOLIDWORKS software to evaluate the pressure distribution on the inner and outer layers of the flexible socket. Findings The hardness and stiffness of the fabricated flexible inner socket gradually increased with the weight ratio of rice husk ash-to-silicone rubber, so when it was in contact with the skin, it approximated the stiffness and hardness of the skin to ensure comfort, and when reaching a higher value in the socket contact layer, it prevented penetration through the flexible inner socket. In addition, the pressure distribution at the external layer of the flexible inner socket has improved. Research limitations/implications A budget of US$500 limited the research to create a flexible inner socket that keeps the socket from penetrating the skin. Practical implications The FGM technique created a flexible inner socket that balances hardness and stiffness to ensure comfort and prevent wounds for its users, lower limb amputees. The commercial value resides in the accessibility of a secure and comfortable flexible inner socket for amputees worldwide, enabling them to overcome the issue of excessive stiffness typically associated with sockets made using the direct method. Originality/value This study introduces the use of FGM to fabricate a flexible inner prosthetic socket with enhanced stiffness and hardness distribution. The approach of using varying weight fractions of rice husk ash-to-silicone rubber to improve the comfort and flexibility of prosthetic sockets is a novel contribution to the field. Given the high stiffness of flexible internal sockets and their ability to maintain flexibility in the part in contact with the skin, such sockets manufactured using this method prevent pain and skin ulcers that previously occurred when sockets are manufactured via the direct method.

Early crack resistance and life cycle assessment of seawater-mixed sintered sludge cement paste

Due to the accelerating effect of chloride and sulfate on the hydration of clinker, seawater-mixed cement (SC) paste is more prone to brittle cracking. Herein, this research systematically investigates the early crack resistance of seawater-mixed sintered sludge cement (SSSC) paste based on splitting tensile test and restrained squared eccentric ring test. The microstructure characteristics characterized by mercury intrusion porosimetry and scanning electron microscopy are combined to reveal the enhancement mechanism of sintered sludge ash (SSA) on SC paste, and a life cycle assessment is conducted around its carbon footprint. The results indicate that the SSA incorporation causes a continuous increase of 24.4 % in the splitting tensile strength of SSSC paste. Meanwhile, the digital image correlation technology accurately captures the strain and displacement fields composed of crack propagation, which tends to be symmetrically distributed and reduces the crack width by 30 %. During the inhomogeneous restrained shrinkage process, as the SSA increases, the crack deviation of the SSSC paste first magnifies and then reduces, the crack width decreases, and the cracking time extends. The pozzolanic activity of SSA is more active in SC paste, which significantly promotes the secondary accumulation of C-S-H and the increase of gel pore volume. This effectively reduces the risk of brittle cracking caused by uneven distribution of paste stiffness due to hydration acceleration during seawater mixing. In addition, replacing 50 % cement with SSA only results in a total of 4.1 % carbon emissions in SSSC paste and a 47.8 % reduction in global warming potential from sludge transportation to activation treatment, demonstrating significant environmental advantages.