Deformation Capacity Research Articles

Numerical evaluation of the internal fracture mechanism of horizontal loop connections in precast elements under the influence of transverse reinforcement

AbstractThis study numerically evaluated the flexural capacity and fracture mechanism of precast reinforced concrete beams connected with in situ horizontal loop connections employing the three‐dimensional rigid body spring model (3D‐RBSM) for modeling of concrete and beam elements (BEs) for modeling of steel, respectively. The research analyzed the performance of continuous horizontal loop connections with and without transverse reinforcement, considering varying vertical spacing between loops and transverse steel ratios. The numerical model effectively captured the test load displacement relationships by incorporating the model parameters like Young's modulus, tensile strength, fracture energy, compressive strength, cohesion, and angle of internal friction for concrete along with mechanical properties of steel and revealed that loop joints without transverse reinforcement exhibited loop type failure. In contrast, specimens with transverse reinforcement improved the peak load and caused compression failure. It was discovered that transverse rebars on the continuous side of the joint experience more strain; particularly, the maximum strain occurred in the corner rebars within the curved sections of U‐rebars. Moreover, the increased vertical spacing between the loop rebars increased the diagonal crack propagation and demonstrated the loop‐type failure. Further, a larger circumferential area of transverse rebar offered greater bond strength and confinement to the concrete core and reproduced the maximum deformation capacity, ductility, and compression failure.

Compression performance of cross-shaped column of modular wall light steel concrete composite frame structure

This paper aims to investigate the compression mechanical properties of cross-shaped column of modular wall light steel concrete composite frame structure (referred to as LSC-CSC) and establish the calculation method of compressive bearing capacity. Nine groups of full-length columns were tested under axial loading and eccentric loading, considering three parameters: length, eccentricity and steel thickness. The experiment revealed that the LSC-CSC had high vertical bearing capacity and deformation capacity. The failure of specimens was mainly caused by the crushing of the concrete and the buckling of the steel skeleton. On the basis of the test, 20 refined FE models were established to carry out the multi-parameter analysis. The results show that the peak bearing capacity increases as the eccentricity, concrete strength and steel thickness increase. The value range of the parameters is given. The thickness of steel ranges from 2.5 mm to 3.5 mm, the concrete strength should not exceed C50 and the slenderness ratio should not exceed 36.32. Finally, the compression bearing capacity calculation formula of LSC-CSC is proposed, and the reliability of the formula is verified by comparing formula calculation results with test results, whose maximum error is within 15 %.

Punching failure and analytical model for rectangular flat slabs with equal flexural capacities in orthogonal directions

Despite the practical use of rectangular flat slabs with equal flexural capacities in orthogonal directions, their punching behavior has not been addressed. In this paper, the mechanical behavior of such slabs under varying tensile reinforcement ratios and plan dimensions has been investigated, using nonlinear finite element analysis in ABAQUS. Initially, the numerical model of the interior slab-column connection under static vertical loads was developed and thoroughly verified using 20 symmetrical and 9 asymmetrical specimens, covering wide variations in various parameters. Subsequently, parametric studies were conducted on rectangular slabs with equal flexural capacities in both directions, utilizing 54 simulations. The results indicated that the slab aspect ratio strongly affected the load-rotation curves, tensile reinforcement stress, cracking patterns, and shear forces in both directions, as well as their symmetry, despite being designed with equal flexural capacities in orthogonal directions. A novel approach, derived from the critical shear crack theory (CSCT), was developed for this slab type and then compared with existing models. It is noted that the ACI code cannot accurately predict the punching capacity. Although the EN1992–1-1 (2023), MC2010, and CSCT models accurately predict punching capacity, especially when the MC2010 and CSCT models account for two directional rotations, they lack in predicting deformation capacity. However, the proposed model offers accurate predictions for punching and deformation capacities. Its innovations include refining the load-rotation equation, validating the CSCT failure criterion, and quantifying the non-uniform shear force between orthogonal directions.

Experimental research and numerical simulation of a modular composite steel frame structure

Corrugated steel plates are widely used in modular structures because they can serve as enclosure components of the modular structures and provide a high lateral resistance to their modules. To meet the structural and functional requirements of a large ground floor bay of a modular structure, such as a modular building, a modular frame structure is often used on the first floor of the structure, and then a modular composite structure with an upper corrugated steel plate and a lower frame structure is formed. The seismic performance and a simplified analysis model of such the modular composite structure with the vertical bolted inter-module connection (MCS) were studied. A full-scale quasistatic test was conducted on the two-storey plane MCS, and the load-displacement curve, failure mode, deformation mode, strain response, and ductility of the structure were obtained. The test results showed that the failure mode of the MCS was related to the formation of a plastic hinge at the end of the floor beam of its lower frame structure and that an opening gap was present in the bolted inter-module connection region. The results also revealed that the bearing capacity of the structure had remained unchanged as the inter-storey drift ratio reached 0.04rad and that the structure had a ductility coefficient > 4.0 along with an excellent plastic deformation capacity. A refined finite element (FE) model of the MCS was established, and the numerical simulation results pertaining to the failure mode and load displacement curve of the MCS agreed well with the corresponding experimental results. The force transfer mechanism of the bolted inter-module connection in the MCS was confirmed through the verified FE model. A simplified analysis model of the MCS was also established based on the stiffness of the corrugated plates and the effective length of the corner fittings of the bolted inter-module connections. The bearing capacity of the MCS obtained by the simplified FE modeling is compared with that obtained by the experiment, and the error is within 6%. The simplified analysis model can provide a basis for the design of such the MCS.

Research on a New High-Damping Viscoelastic Damper: Development, Experiment and Modeling

Viscoelastic (VE) dampers are promising control devices for mitigating the vibration of structures. The performance of these dampers depends on the energy dissipation and deformation capability of VE materials. This paper aims to develop a VE damper with high damping to improve the energy dissipation performance of existing dampers. A new VE material with high damping was developed and tested for its shear mechanical properties. A total response control viscoelastic (TRC-VE) damper was designed and manufactured using the new high-damping VE material. The performance of the TRC-VE damper was comprehensively investigated in terms of strain, frequency and size dependence. A five-element shear mechanical model was proposed to simulate the shear mechanical behavior of the TRC-VE damper. Results indicated that the TRC-VE damper has remarkable energy dissipation and excellent deformation capacities. The five-element shear mechanical model can accurately simulate the shear mechanical properties of the new high-damping TRC-VE damper.

Experimental and formula deduction on the mechanical performance of Fang in Dou-Gong of Song dynasty

In Song dynasty, Dou-Gong construction techniques, Tou-Xin-Zao and Ji-Xin-Zao, varied by the number of Fang connecting to the exterior. This study examines the impact of Fang connections on the mechanical characteristics of Dou-Gong. Six full-scale models were constructed and subjected to quasi-static loading tests in the horizontal Beam and Fang directions under vertical load. The hysteresis behavior, deformation, and stiffness variations were obtained and analyzed. The test results revealed the hysteresis curve of Dou-Gong developed into a flat shape, with good deformation recovery ability and seismic performance. Beam-direction loading led to brittle failure, with Dou-Gong having fewer Fang experiencing bearing capacity loss and those with more Fang succumbing to overturning. Beam-direction stiffness rose by approximately 29% as the number of connecting Fang increased. Fang-direction loading induced ductile failure, predominantly characterized by overturning. Notably, Fang-direction stiffness remained largely unchanged by the varying number of connecting Fang. Dou-Gong slip deformation ratio decreased by 5 -10% as the number of Fang increased. Furthermore, Fang-direction exhibited about 10% greater slip deformation capacity than the Beam-direction. Based on the force transfer mechanism of Dou-Gong components, a stiffness formula for the elastic stage of Dou-Gong in the Beam-direction and Fang-direction was established and validated against experimental data.

Seismic Drift Estimates of Corroded Piers: A Multihazard Approach Utilizing 3D‐IDA Analysis With Time Stamps Considering Climate Change Effects

ABSTRACTThe compounding effect of seismicity, exposure to corrosion, and climate change in regions such as North America pose significant challenges for bridge design engineers, as the multihazards impact on the seismic performance of bridge structural systems remains underexplored. While drift ratio is the most widely used parameter in probabilistic seismic demand assessment, existing models predominantly concentrate on seismic intensity levels, overlooking the increase in demand and the reduced deformation capacity, both being affected by corrosion‐induced damage and climate change. Therefore, developing an evaluation framework for the multihazard seismic vulnerability of deficient bridges is an emerging priority in the field. To address this need, a methodology is proposed here that uses data collected from field inspections to quantify the accumulation of historic corrosion damage and forecast future corrosion propagation. Climate change scenarios derived from future climate forecast models are used to project the temperature and relative humidity changes up to the year 2100; the rate of reinforcement corrosion is quantified based on these scenarios. Utilizing incremental dynamic analysis (IDA) across a projected timeline, expressions are derived for the time evolution of drift demand in existing reinforced concrete circular piers over the lifetime of the bridge. By using these results, drift demand expressions are derived for different climate change scenarios. The influence of design parameters (e.g., concrete cover, chloride diffusion coefficient, and aging factor) on the drift demands is evaluated using Monte Carlo simulation. The proposed expressions serve as a benchmark for bridge engineers to study the seismic performance of bridge structures in multihazard environments.

Study on Damage Characteristics and Failure Patterns of Sandstone Under Temperature–Water Interactions

In modern tunnel construction, complex environments with high geothermal gradients and abundant groundwater are frequently encountered. To investigate the damage and failure mechanisms of sandstone under the combined effects of temperature and water, uniaxial compression tests were conducted on sandstone at different temperatures (25 °C, 55 °C, 85 °C, and 95 °C) and soaking durations (0.5 h, 1 h, and 3 h). The acoustic emission (AE) signals and energy evolution during the damage and failure processes were analyzed, revealing the damage characteristics and failure mechanisms of sandstone. The results indicate the following: (1) As the temperature increases, under the 3 h condition, the water content of sandstone is highest at 55 °C, reaching 3.01%, and the thermal expansion effect of sandstone is not obvious. Under the conditions of 85 °C and 95 °C, the thermal expansion effect leads to a decrease in the water content, enhances the water absorption softening effect, increases the plastic deformation capacity of sandstone, and weakens its brittle failure capacity. (2) When soaked for 0.5 h and 1 h, the maximum acoustic emission ring count and maximum acoustic emission energy of sandstone increase initially, then decrease, and subsequently increase again as the temperature rises, while the cumulative acoustic emission ring count gradually increases with temperature. Under the 3 h soaking condition, the maximum ring count, maximum energy, and cumulative ring count of sandstone at all temperatures show a consistent increasing trend with temperature. (3) The increase in soaking time reduced the damage variable of sandstone, with the largest reduction of 54.17% under the 3 h condition. At different temperatures, the damage variable of sandstone was smallest at 55 °C, only 0.33. (4) Sandstone primarily experiences tensile failure under different temperatures and soaking times. The extension of soaking time promotes the development of shear cracks, while the increase in temperature can effectively promote the expansion of tensile cracks. The research results provide certain theoretical references for the damage and failure of surrounding rock in modern tunnel construction.

Seismic Behavior of Damaged Ancient Timber Buildings: Multi-Scale Finite Element Model, Performance Degradation, and Experimental Verification

ABSTRACT This paper presents a multi-scale modeling methodology for predicting the hysteretic behaviors of damaged ancient timber joints as well as the global seismic behavior of damaged ancient timber structures. The mortise and tenon (M-T) joint and column foot (C-F) joint, as the key load-bearing components of the structure, were modeled using detailed solid elements. Timber components that were large in size and not easily damaged were simulated using beam element. The interface connection between the detailed elements and beam elements was achieved using the displacement coordination method. The detailed and the multi-scale finite element models (FEMs) for M-T and C-F joints were established using the ABAQUS. The hysteretic curves, failure modes, and computing efficiency of two types of FEMs were compared. The feasibility of interface connection method of the multi-scale FEM was validated through cyclic loading test results of the joints. Based on the verified multi-scale interface connection method, detailed and multi-scale dynamic analysis models for a hall-type ancient timber building were developed using the ABAQUS, and validated through shaking table tests in terms of their dynamic characteristics and responses. Additionally, parametric analyses were performed to investigate the effects of the gaps between the mortise and tenon, as well as damage to the C-F joint, on the seismic behavior of ancient timber buildings. Degradation formulas for the key parameters of seismic behavior for damaged ancient timber structure were established. It is found that the model predictions were in good agreement with the test results. Under minor earthquakes, damage to M-T and C-F joints had negligible effects on the overall deformation capacity of the structure. However, under moderate earthquakes, a damage degree of 0.3 in the M-T joint resulted in a 6.20% reduction in the maximum inter-layer drift ratio of the Dou-Gong story, while the maximum inter-layer drift ratio of the column-frame story increased by 8.33%. With a damage degree of 0.52 in the C-F joint, the maximum inter-layer drift ratio of the Dou-Gong story and the column-frame story of the structure reduced 17.92% and 12.50%, respectively.

Assessment of the fracture properties of mortars reinforced with synthetic fibers

AbstractThis paper investigates the post‐cracking behavior of mortars reinforced with synthetic polypropylene fibers. To three series of mortars, normal strength (NSM), high strength (HSM), and high strength with fly ash (HSMFA), short and long, was introduced at 0.6% and 1% by volume, respectively. Pre‐notched 4 × 4 × 16 cm were used for 3‐point flexural tests, and the digital image correlation (DIC) method was employed to assess the load‐CMOD curves. Based on the experimental curves, a tri‐linear stress‐crack opening (σ‐w) relationship was used to develop an analytical model for the Mode I crack propagation, and the inverse analysis method was applied to optimize the model's parameters. The obtained parameters were compared to the fib MC2010 characteristic values related to serviceability and ultimate limit states. The results show that short fiber‐reinforced mortars exhibit a softening behavior regardless of the fiber dosage after a rapid drop once the tensile strength has been achieved. The three mortars incorporating long fiber reinforcement exhibit a very high deformation capacity and hardening behavior. For NSM, fibers appear to be more effective than HSM and HSMFA. All materials achieve the ultimate fracture opening of 2.5 mm, as defined by the fib MC2010, except 0.6% long fiber‐reinforced HSMFA. Compared to the reference mixture (mixture without fibers), adding synthetic fibers to the mortar did not exhibit a significant environmental and health impact.

Assessment of corrosion attack morphology on reinforced concrete structures exposed to chlorides

AbstractChloride‐induced corrosion of the reinforcement steel is the main degradation mechanism for reinforced concrete, considerably affecting the load and deformation capacity of structures. Despite its importance, there is limited knowledge about the morphology of corrosion attacks and accordingly, relatively crude assumptions are generally made when considering corrosion in structural analyses. Improved understanding could reduce maintenance costs and extend the service life of structures. This study presents a systematic documentation and analysis of more than 600 corrosion attack morphologies, both from observations on actual engineering structures and from laboratory specimens (X‐ray computed tomography data from previous studies). Findings reveal that corrosion attacks—regardless of age, concrete type, or whether occurring in structures or laboratory specimens—without exception grow laterally and longitudinally along the reinforcement bar, rather than in depth. This shallow morphology deviates from the conventional description of pitting corrosion in the literature. Therefore, we propose using the term ‘corrosion attack’ instead of ‘corrosion pit’ for better differentiation. We discuss different mechanism that may lead to this growth pattern. Moreover, implications for the consideration of corrosion in structural analysis are assessed. A comprehensive database of the documented corrosion attacks is provided to enhance existing service life models, offering substantial data for probabilistic modeling of input parameters.

Freeze-thaw Effect on the mechanical properties of different wood species: impact of moisture content variations, microscopic morphology, and thermal modification in a selected species

This study investigates changes in the mechanical qualities (such as the deformation capacity, compressive strength, and compressive stiffness) of structural timber due to freezing and thawing cycles. Ten (10) specimens, including nine (9) distinct wood species, were assessed, with one from a thermally modified version of a specific species. The findings indicated that by the end of 60 full freeze-thaw cycles, the mechanical qualities had generally deteriorated for all wood species; however, the rate of reduction in these properties varied depending on the type of wood. The maximum reduction of the deformation capacity was evaluated as 16.2% for Iroko, and the lowest was 0.1% for Mahogany. Again, an average decrease of 29.5% was observed in the stiffness of Mahogany, while the least change in the stiffness was 4% for Soft Maple wood. To expound on the possible changes in the wood surface profile and fibers during freeze and thaw cycles of 20, 40, and 60, a scanning electron microscope (SEM) analysis was also conducted. It was observed that the overall fiber density variation, due to the distribution of developed cracks and pores, accounts for the different responses in each complete set of cycles. Some of the wood species showed a progressive decrease in the fiber density from 0 to 60 freeze-thaw cycles, while others exhibited some surging effects. This explains the possibility of some of the wood’s mechanical properties increasing between cycles of freeze-thaw action (before finally reducing). For the first time, the impact of prior thermal treatment on the freeze-thaw resistance of wood was also investigated. It was seen that thermally modified Red Oak showed improved resistance to freeze-thaw in terms of compressive stiffness when compared to untreated Red Oak. However, the deformation capacity and compressive strength declined in the thermally modified wood compared to the untreated wood.

Calcium aluminate cement based high early strength engineered cementitious composites with recycled artificial flaws

Engineered Cementitious Composites (ECC) is an ideal repair material due to its high durability and ductility. However, providing ECC with high early strength is challenging since strength and ductility, which are key to crack-free repair, are also interdependent. Thus, it is necessary to use artificial flaws in order to keep the ductility at reasonable levels while increasing the strength. This study uses calcium aluminate cement, a non-portland cement, as the primary binder to attain the early strength in the production of high early strength ECC for the first time. Besides, expanded glass and crumb rubber, both made by recycling waste materials, were included as artificial flaws to enhance ductility. The performance of designed high early strength ECC was assessed through mechanical, abrasion, shrinkage and non-destructive tests and compared with high early strength portland cement based ECC. It is revealed that a minimum compressive strength of 28.9 MPa and flexural strength of 7.1 MPa could be attained even at the age of as early as 6 hours after casting. Nevertheless, deformation capacities were significantly improved after 24 hours following the casting by the use of both artificial flaws. In addition, acceptable drying shrinkage and abrasion resistance values were obtained.

Strain penetration effects on lateral strength and deformation capacity of U-shaped walls

Strain penetration effects on lateral strength and deformation capacity of U-shaped walls

Seismic performance enhancement of brick masonry walls by retrofitting with nominal RC bands: a study of diagonal compression tests

In-plane performance of un-reinforced brick masonry (URBM), retrofitted with nominal Reinforced Concrete (RC) bands, was investigated under diagonal compression tests using full-scale and half-scale specimens. The retrofitting technique is cost-effective, reliable, simple, easily implementable, and minimally intrusive. Six URBM wall specimens (three full-scale and three half-scale) served as control specimens, and similarly, six (three full-scale and three half-scale) were retrofitted with RC bands. All specimens were tested under diagonal compression in a computer-controlled servo-hydraulic universal testing machine using displacement-controlled scheme. Data on applied force and corresponding wall displacements were recorded. Responses of retrofitted specimens were compared with control specimens in terms of strength, deformation capacity, and failure patterns. Retrofitted specimens exhibited progressive damage due to ductile failure, showing a significantly increased deformation capacity and providing sufficient warning time before collapse. However, control specimens showed sudden catastrophic collapse due to sliding of bed-joints. Overall, retrofitted specimens demonstrated a significant enhancement of ductility. Next, a semi-empirical prediction formula for diagonal load capacity was established through macro-modelling approach and subsequent regression analysis to capture experimental results. From results, the proposed retrofitting scheme provides a promising solution for seismic risk reduction of existing deficient masonry structures in rural areas of the Indian subcontinent and elsewhere.

Effects of Out-of-Plane Deformation of the Base Plate on the Structural Behavior of an Exposed Column Base

This study explores the behavior of exposed column bases in concrete-filled steel tubular (CFST) and steel structures, with a focus on cases where base plates yield due to out-of-plane deformation. Understanding these mechanisms is crucial for improving the design and safety of these structures. Experimental tests and numerical analyses were conducted on four specimens to investigate their lateral load versus drift angle behavior. The tests demonstrated that base plates exhibited sufficient deformation capacities and enhanced hysteresis characteristics. Finite element method (FEM) analysis successfully traced the load–deformation relationships observed in the tests, providing detailed insights into stress distribution on the base plates. Based on these analyses, a simplified calculation method was proposed to evaluate the horizontal strength of exposed column bases. The proposed method showed excellent agreement with the test results, highlighting its potential as a practical tool for structural design.

Multi-parameter coupling modeling method and hybrid mechanism of concrete-encased CFST hybrid structures

Concrete-encased concrete-filled steel tubular (CFST) hybrid structures consist of encased CFST components and reinforced concrete (RC) encasement, posing unique challenges related to their hybrid mechanisms and coupling effects. This study addresses these issues by proposing an automatic and efficient Finite Element (FE) modeling method, which accounts for multiple constitutive models of confined concrete, meticulous grid division and reasonable interaction. The FE modeling method was packaged with a user-friendly graphical interface in the software ‘Auto CECFST’, which has been shared on GitHub(https://github.com/CECFST/Auto-CECFST.git). The modeling method has been verified by test results on the strength, stiffness and deformation capacity. Utilizing the refined FE modeling method, 7776 FE models are generated based on an orthogonal combination of 7 critical parameters of concrete-encased CFST hybrid structures. To accurately define failure modes, stress ratio (φ) was proposed to achieve quantitative analysis on the failure mode, followed by a comprehensive investigation into the full-range analysis of the hybrid mechanism of two components. Moreover, further exploration focused on multi-parameter coupling effects of critical mechanism characteristics, including strength, stiffness, and deformation capacity, elucidating the hybrid mechanism and mechanical similarities between single and multi-chord structures. Based on the above analysis, the balance of strength and deformation ability could be achieved by certain parameter ranges. Finally, available strength and stiffness calculation methods are validated against experimental and FE results under three typical failure modes, revealing the advantages and limitations of calculation methods on the basis of mechanics and data statistics, which provides a basis for security structural design.

3D printing of multiscale biomimetic structural electrodes: achieving ultrahigh deformability and areal capacity for Li-ion batteries

3D printing of multiscale biomimetic structural electrodes: achieving ultrahigh deformability and areal capacity for Li-ion batteries

Seismic Collapse Risk Assessment and Fragility Analysis of Reinforced Masonry Core Walls with Boundary Elements Using the FEMA P695 Methodology

In the past, the primary objective of structural design codes was centred around ensuring human life safety, with a strong focus on preventing structural collapse. This approach predominantly relied on force- or strength-based criteria as the basis for design. Nevertheless, a notable shift has occurred recently, transitioning the design philosophy from 'strength' towards a 'performance'-based approach. This shift signifies a growing recognition that strength and performance are not identical. However, to adopt the performance-based seismic design approach, it is essential to develop precise models for estimating damage and potential losses associated with various seismic force-resisting systems (SFRSs). Fragility functions are widely interpreted among the most prevalent damage and loss models. They establish a crucial link between specific demand parameters and the likelihood of exceeding various damage states. Although reinforced masonry (RM) structures have recently gained popularity, the seismic design of mid- to high-rise RM structures is still challenging because it requires a reliable SFRS capable of providing the needed ductility and capacity. Therefore, the main objective of this study is to evaluate the key seismic performance parameters (i.e., system overstrength and ductility) and to perform a collapse capacity risk assessment of reinforced masonry core walls with boundary elements (RMCW+BEs) as the main SFRS in RM structures. The current study utilizes the applied element method (AEM) implemented in the Extreme Loading for Structures software (ELS) to model three RM structures with various heights (10-, 15-, and 20-story buildings). Nonlinear pseudo- static pushover analysis was performed to quantify the ductility and overstrength of the proposed RM system following the FEMA P695 guidelines. In addition, an incremental dynamic analysis (IDA) was carried out to assess the seismic collapse risk of RMCW+BEs by generating system-level-based fragility curves. The results showed that the proposed RM system provides the needed ductility, overstrength and deformation capacity for a ductile SFRS for typical mid- and high-rise RM buildings. Furthermore, the developed collapse fragility curves verified excellent seismic performance, negligible collapse probability values and high reserved collapse capacity at the maximum considered earthquake (MCE) design level. The findings of this study significantly contribute toward adopting RMCW+BEs as an effective SFRS for typical RM buildings in the next generations of North American masonry design standards.

Design, fabrication, and testing of a new soft-pouch robot with 6 degrees of freedom to expand the reach of open and endonasal skull base approaches

OBJECTIVE Most robots currently used in neurosurgery aid surgeons in placing spinal hardware and guiding electrodes and biopsy probes toward brain targets. These robots are inflexible, cannot turn corners, and exert excessive force when dissecting and retracting brain tissue, limiting their applicability in cranial base surgery. In this study, the authors present a novel soft-pouch robot prototype driven by compressed air and capable of gentle tissue manipulation. The robot is manufactured with technology developed by the authors, with multiple bidirectional bending points and a miniature camera running through the robot’s central channel. METHODS A soft, pneumatically driven pouch manipulator was created using a novel rapid and scalable system (integrated multilayer pouch robots with inkjet-patterned thin films). Made from 4 layers of thin, low-density polyethylene films, the manipulator has a thin deflated profile (152 µm) and contains 5 independent bidirectional joints with 50° range in each direction, as well as a wrapping end-effector. The robot carries a camera through its central channel. Four cadaveric models were used to demonstrate the robotic prototype being maneuvered inside different anatomical structures during simulated endonasal and posterior fossa approaches, with a manually positioned robot base and manually controlled air pressures. RESULTS The robot is a pneumatically driven, soft-continuum manipulator with 12 control inputs and 6 independently controllable degrees of freedom. This design enables in-plane obstacle avoidance and orientation control. The robot is trapezoidal-shaped, with a total weight of 0.4 g, a 10-mm-wide distal end, and a length of 138 mm. The variable production cost (materials cost) of the manipulator is approximately $1. The manipulator is maneuvered to enter the maxillary sinus and through the endonasal corridor, demonstrating its potential use for anterior skull base approaches. It is also successfully maneuvered around the pons in a simulated retrosigmoid approach. CONCLUSIONS This robot offers a promising solution for safely maneuvering through narrow surgical windows encountered during skull base approaches. The multiple bending points of the robot, combined with its passive deformation capacity, allow it to turn around immovable structures, expanding the reach of surgical openings. The cost-effectiveness, rapid production, and scalability of the robot represent additional advantages.