MPa Young's Modulus Research Articles

Phase-Segregated Ductile Eutectogels with Ultrahigh Modulus and Toughness for Antidamaging Fabric Perception.

Ionogels are extremely soft ionic materials that can undergo large deformation while maintaining their structural and functional integrity. Ductile ionogels can absorb energy and resist fracture under external load, making them an ideal candidate for wearable electronics, soft robotics, and protective gear. However, developing high-modulus ionogels with extreme toughness remains challenging. Here, a facile one-step photopolymerization approach to construct an acrylic acid (AA)-2-hydroxyethylacrylate (HEA)-choline chloride (ChCl) eutectogel (AHCE) with ultrahigh modulus and toughness is reported. With rich hydrogen bonding crosslinks and phase segregation, this gel has a 99.1MPa Young's modulus and a 70.6MJm-3 toughness along with 511.4% elongation, which can lift 12000 times its weight. These features provide extreme damage resistance and electrical healing ability, offering it a protective and strain-sensitive coating to innovate anticutting fabric with motion detection for human healthcare. The work provides an effective strategy to construct robust ionogel materials and smart wearable electronics for intelligent life.

Highly Breathable, Stretchable, and Tailorable TPU Foam for Flexible Gas Sensors.

Continuous real-time monitoring of air quality is of great significance in the realms of environmental monitoring, personal safety, and healthcare. Recently, flexible gas sensors have gained great popularity for their potential to be integrated into various smart wearable electronics and display devices. However, the development of gas sensors with superior sensitivity, breathability, and stretchability remains a challenge. Here, a new high porosity thermoplastic polyurethane (HP-TPU) foam was reported for gas sensors, which exhibited large three-dimensional network structures and excellent mechanical properties. The HP-TPU foam was achieved by using a simple steam-induced method, which was suitable for mass production. The unique structure endowed this foam with 77.5% porosity, 260% strain ability, and 0.45 MPa Young's modulus, which improved 35, 31, and 80%, respectively, compared to previously reported traditional TPU foam (T-TPU) prepared by the drying method. In addition, the foam presented high gas permeability (312 g/m-2, 24 h) and excellent stability, and it remained undamaged even after 2000 cycles at 70% strain. The sensing material was coated on a PET flexible interdigital electrode and sandwiched between two HP-TPU foam layers for a gas sensitivity test. Due to the easy diffusion of gas between the pores and contact with the sensing materials, the HP-TPU foam exhibited a significant reduction of 85% in average response time and 46% in average recovery time, compared to the T-TPU foam. A wearable sensing device, comprising sensing, data processing, and wireless transmission modules, was successfully developed to enable outdoor testing and achieved a detection range at the ppb level. Finally, the cytotoxicity test results confirmed that this flexible gas sensor did not harm human health. These results proved that this HP-TPU foam was an ideal matrix for the flexible gas sensor, exhibiting great application potential in the fields of seamless human-machine integration.

Incorporation of Bifidobacterium breve in sodium caseinate‐edible film: Physicochemical properties, viability, and antibacterial activity

AbstractThe addition of probiotic bacteria creates added value to food products wrapped with edible film. Hence, this study aimed to develop sodium caseinate (NaCas) edible film containing Bifidobacterium breve. The edible film was prepared by using different NaCas concentrations (2%–6% wt/vol), glycerol, and B. breve suspension (1% vol/vol). The edible film without probiotics was used as a control film. The optimized 3% (wt/vol) NaCas‐B. breve edible film had a viable cell count of 7.07 log10 CFU/g, thickness of 0.16 mm, 63.50% water solubility, 14.04% moisture content, the color difference (ΔE) <2.59, 3.31 mPa tensile strength, 35.73% elongation at break, and 0.10 mPa Young's modulus. Furthermore, the NaCas‐B. breve edible film had also shown inhibition against Escherichia coli, Klebsiella pneumoniae, and Salmonella enterica. The desirable physicochemical properties, high viability, and antibacterial properties of 3% (wt/vol) NaCas‐B. breve edible films may enable their future use as bioactive packaging for food products.

Formation of PLGA-PEDOT: PSS Conductive Scaffolds by Supercritical Foaming.

The usage of conjugated materials for the fabrication of foams intended to be used as therapeutic scaffolds is gaining relevance these days, as they hold certain properties that are not exhibited by other polymer types that have been regularly used until the present. Hence, this work aims to design a specific supercritical CO2 foaming process that would allow the production of porous polymeric devices with improved conductive properties, which would better simulate matrix extracellular conditions when used as therapeutic scaffolds (PLGA-PEDOT:PSS) systems. The effects of pressure, temperature, and contact time on the expansion factor, porosity, mechanical properties, and conductivity of the foam have been evaluated. The foams have been characterized by scanning electron and atomic force microscopies, liquid displacement, PBS degradation test, compression, and resistance to conductivity techniques. Values close to 40% porosity were obtained, with a uniform distribution of polymers on the surface and in the interior, expansion factors of up to 10 orders, and a wide range of conductivity values (2.2 × 10-7 to 1.0 × 10-5 S/cm) and mechanical properties (0.8 to 13.6 MPa Young's modulus in compression test). The conductive and porous scaffolds that have been produced by supercritical CO2 in this study show an interesting potential for tissue engineering and for neural or cardiac tissue regeneration purposes due to the fact that electrical conductivity is a crucial factor for proper cell function and tissue development.

Robust and Flexible 3D Photothermal Evaporator with Heat Storage for High‐Performance Solar‐Driven Evaporation

AbstractSolar‐driven interfacial steam generation serves as an alternative strategy to alleviate the emergency of the global freshwater shortage. Compared to traditional 2D evaporators, 3D evaporators have drawn further attention for their excellent evaporation performance. However, large volume 3D evaporators suffer from problems related to higher vulnerability to damage and less portable storage. Worse still, 3D evaporators equally behave poorly in dark conditions. Herein, a robust and flexible 3D hydrogel/fiber evaporator mounted with solid–solid phase change materials (SPCMs) for efficient photothermal desalination is reported. The hydrogel fills the spaces of fibers and not only forms a topology‐like structure to strengthen the sunlight absorption (≈0.1% optical transmittance and ≈10% reflectance), but also reinforces the mechanical strength and elasticity of the evaporator (≈4 MPa tensile strength and ≈23 MPa Young's modulus). Notably, highly thermally‐conductive SPCMs fulfill a dual function under light‐dark conditions, facilitating a 3D evaporator for absorbing energy from high‐temperature environment under daylight, and releasing latent heat to sustain evaporation when light is turned off, ultimately achieving evaporation rates of 3.80 and 0.31 kg m–2 h–1 under different conditions. Such a durable 3D hydrogel/fiber evaporator with dramatic evaporation performance opens up promising prospects for freshwater production in remote areas.

Mechanical and physical characterizations of compatibilizer‐free recycled plastics blend composites modified with carbon nanotube and clay nanofiller

AbstractExcessive amount of disposable and reusable plastic wastes has increasingly gained a great environmental concern. This present article aims to investigate the individual effect of multiwalled carbon nanotubes (MWCNTs) and clay loadings at 0.5, 1.0, 2.0, 4.0, and 6.0 phr on the tensile, impact, density, and water absorption properties of polymer blend made from recycled high‐density polyethylene and recycled polyethylene terephthalate. Both nanocomposites were melt‐blended using a twin screw extruder before compression molding. For MWCNT nanocomposite, 4 phr showed the optimum tensile strength (14.5 MPa), Young's modulus (587.4 MPa), and strain at break (4.2%) as compared to other loadings. For clay nanocomposite system, the optimum tensile properties (13.9 MPa tensile strength, 525.7 MPa Young's modulus, and 4.7% strain) were achieved at 1 phr. The impact strength of the nanocomposites was reduced with both nanofillers' content. With the increment of MWCNT and clay loadings, the percentages of water uptake increased but the values were still considered low (<0.26% upon 35 days immersion) capacity. These research findings with the effect of nanofiller types and loadings were statistically significant as proven in ANOVA analysis. This study formalizes a chemical‐free environmental strategy to produce nanocomposite as a plastic‐replacement product.

Long-Term Recruitment of Endogenous M2 Macrophages by Platelet Lysate-Rich Plasma Macroporous Hydrogel Scaffold for Articular Cartilage Defect Repair.

After cartilage damage, a large number of monocytes/macrophages infiltrate into adjacent synovium and the resident macrophages in synovial tissue transform to activated macrophages (M1), which secrete pro-inflammatory cytokines to induce sustained inflammation and chondrocyte apoptotic. However, current clinical therapies for cartilage repair can rarely achieve long-term anti-inflammatory regulation and satisfactory outcomes. Herein, a platelet lysate-rich plasma macroporous hydrogel (PLPMH) scaffold with around 100µm pore size and 1.25MPa Young's modulus is developed to sustainedly recruit and polarize endogenous anti-inflammatory macrophages (M2) for improving cartilage defect repair. PLPMH scaffold can steadily release sphingosine1-phosphate and proteins via gradual degradation, thus inducing M2 macrophages migration or resting (M0) macrophages migration and then polarization to M2 phenotype, and improving the secretion of anti-inflammatory cytokines. Furthermore, PLPMH scaffold exhibits negligible inflammatory responses in vivo and promotes endogenous M2 macrophage infiltration in large numbers and long-time duration to provide a local anti-inflammatory microenvironment, which even lasts for 42 d. In a rabbit model of cartilage defect, PLPMH scaffold increases the ratio of M2 macrophages and improves cartilage tissue regeneration. These studies support that PLPMH scaffold may have a great potential in articular cartilage tissue engineering by providing an anti-inflammatory and pro-regenerative microenvironment.

Increasing the Microfabrication Performance of Synthetic Hydrogel Precursors through Molecular Design.

Implementation of hydrogel precursors in two-photon polymerization (2PP) technology provides promising opportunities in the tissue engineering field thanks to their soft characteristics and similarity to extracellular matrix. Most of the hydrogels, however, are prone to post-fabrication deformations, leading to a mismatch between the computer-aided design and the printed structure. In the present work, we have developed novel synthetic hydrogel precursors to overcome the limitations associated with 2PP processing of conventional hydrogel precursors such as post-processing deformations and a narrow processing window. The precursors are based on a poly(ethylene glycol) backbone containing urethane linkers and are, on average, functionalized with six acrylate terminal groups (three on each terminal group). As a benchmark material, we exploited a precursor with an identical backbone and urethane linkers, albeit functionalized with two acrylate groups, that were reported as state-of-the-art. An in-depth characterization of the hexafunctional precursors revealed a reduced swelling ratio (<0.7) and higher stiffness (>36 MPa Young's modulus) compared to their difunctional analogs. The superior physical properties of the newly developed hydrogels lead to 2PP-based fabrication of stable microstructures with excellent shape fidelity at laser scanning speeds up to at least 90 mm s-1, in contrast with the distorted structures of conventional difunctional precursors. The hydrogel films and microscaffolds revealed a good cell interactivity after functionalization of their surface with a gelatin methacrylamide-based coating. The proposed synthesis strategy provides a one-pot and scalable synthesis of hydrogel building blocks that can overcome the current limitations associated with 2PP fabrication of hydrogel microstructures.

A multifunctional, one-step gas foaming strategy for antimicrobial silver nanoparticle-decorated 3D cellulose nanofiber scaffolds

Creating nanoparticle-decorated nanofibers in a single step can greatly speed up and scale up the production of scaffolds for various applications. In this study, we report a facile multifunctional method for the simultaneous foaming and synthesis of silver nanoparticles-covered three-dimensional cellulose using sodium borohydride (NaBH4). The physicochemical properties of the 3D cellulose-Ag scaffold were evaluated and compared to 2D CA membranes, including morphology (porous 3D vs flat 2D), mechanical properties (22.72 vs <13 MPa Young's modulus), antibacterial effect (27 vs 0 mm zone of inhibition), and biocompatibility. The findings suggest that our method enables the scaffold to be easily manufactured—indicating it can be used to scale-up manufacturing processes—with high bioactivity, antibacterial effect, and biocompatibility, showing potential as a 3D structure production method for tissue engineering and other relevant applications.

Preparation and Characterization of Polymer Blends Based on Carboxymethyl Cellulose, Polyvinyl Alcohol, and Polyvinylpyrrolidone

Two libraries of crosslinked polymer blends were synthesized and characterized. The polymer blends were prepared from carboxymethyl cellulose, polyvinyl alcohol, and polyvinylpyrrolidone in 1:1:1 ratio using solvent casting method. Two crosslinking agents were used: glyoxal and glutaraldehyde for the first and second libraries respectively. Both crosslinking agents were used in three different ratios (10,15, and 20%). The mechanical properties of the polymer blends were tested using morphology, and swelling ratio methods for the crosslinked polymer blends only. The results confirm that the degree of crystallinity was altered during blending and crosslinking when the original polymer blend compared to itself after crosslinking. The maximum elongation eM% was found when the crosslinking agent ratio was 15%. The polymer blend D with glutaraldehyde as the crosslinking agent had the maximum elongation eM% =17.533, and about 0.565 Mpa Young modulus. While polymer blend B with glyoxal as crosslinking agent had maximum elongation eM% = 11.115, and about 0.593 Mpa Young modulus. Finally, the prepared blends are suitable for adsorption and as an excipient material in pharmaceutical industries.

Multiple H‐Bonding Chain Extender‐Based Ultrastiff Thermoplastic Polyurethanes with Autonomous Self‐Healability, Solvent‐Free Adhesiveness, and AIE Fluorescence

AbstractDeveloping an autonomous room temperature self‐healing supramolecular polyurethane (PU) with toughness and stiffness remains a great challenge. Herein, a novel concept that utilizes a T‐shaped chain extender with double amide hydrogen bonds in a side chain to extend PU prepolymers to construct highly stiff and tough supramolecular PU with integrated functions is reported. Mobile side‐chain H‐bonds afford a large flexibility to modulate the stiffness of the PUs ranging from highly stiff and tough elastomer (105.87 MPa Young's modulus, 27 kJ m−2tearing energy), to solvent‐free hot‐melt adhesive, and coating. The dynamic side‐chain multiple H‐bonds afford an autonomous self‐healability at room temperature (25 °C). Due to the rapid reconstruction of hydrogen bonds, this PU adhesive demonstrates a high adhesion strength, fast curing, reusability, long‐term adhesion, and excellent low‐temperature resistance. Intriguingly, the PU emits intrinsic blue fluorescence presumably owing to the aggregation‐induced emission of tertiary amine domains induced by side‐chain H‐bonds. The PU is explored as a counterfeit ink coated on the predesigned pattern, which is visible‐light invisible and UV‐light visible. This work represents a universal and facile approach to fabricate supertough supramolecular PU with tailorable functions by chain extension of PU prepolymers with multiple H‐bonding chain extenders.

Uniform and graded copper open cell ordered foams fabricated by rapid manufacturing: surface morphology, mechanical properties and energy absorption capacity

Pure copper open cell ordered foams (COCOF) have tremendous applications in the field of thermal mechanical management systems. These foams possess high thermal and electrical conductivity, sufficient mechanical strength and energy absorption capacity because of copper as the parent material. In the present study, the combination of ultrasonic assisted pressureless sintering and 3D printing as a rapid manufacturing technique has been used to fabricate COCOF. Two different unit cell designs, Simple Cubic (SC) and Body-Centered Cubic (BCC) were selected to fabricate uniform foams of three strut sizes 1, 1.3 and 1.6 mm and graded foams with strut size varying from 1 to 1.6 mm. The dimensional deviations of the fabricated COCOF samples from the designed CAD model were found to be less, as compared to the traditional metal printing technique i.e. electron beam melting (EBM). Significant effect on the surface roughness was noticed due to post processing on the fabricated COCOF. The SC and BCC fabricated by COCOF possessed 19-160 MPa Young's modulus, 2.5-25 MPa compressive strength, 2.5-30 MPa plateau stress and 1.2-9.3 MJ/m3 energy absorption capacity. Moreover, the compression deformation behavior of these foams was investigated and found to be in-line with Ashby-Gibson model. However, due to micro-pores in fabricated COCOF, the struts were observed to be crushed during compression. The graded foam, with similar relative density, outperformed the uniform foam in terms of mechanical and energy absorption capacity for both SC and BCC COCOF. Moreover, the present method can be used to fabricate complex multi-functional thermal mechanical monolithic heat exchanger devices.

Dense Ti3AlC2 based materials obtained by SHS-extrusion and compression methods

MAX phases (M: early transitionA:13 and 14 group A-element; X:C and/or N) are ternary carbides/nitrides with a unique combination of metallic and ceramic properties. Bulk MAX phases can be prepared from different starting materials and pre-synthesized powders mostly at high temperature and long sintering time. Here, we prove an efficient one-step technological method to produce bulk MAX phase based materials using self-propagation high-temperature synthesis. We show that bulk materials (relative density of 95.5% and 97.2%) can be produced in the form of plates and rods with 67.5% wt. and 81.9% wt. of MAX phases. The compressive strength of 720 ± 2 and 641.5 ± 2 MPa Young's modulus of 221.5 ± 4 and 198.3 ± 2.8 GPa, and thermal conductivity of 22.9 and 22.3 W m−1 K−1 are achieved as a result of extrusion and compression self-propagation high-temperature synthesis. The sintered materials are good thermal conductors with high mechanical characteristics that can be used as promising materials for high-temperature application.

Engineering Fully Organic and Biodegradable Superhydrophobic Materials

AbstractThe development of fully organic (cellulose/wax based), biodegradable, and hierarchically textured superhydrophobic material, inspired by natural, self‐cleaning plants, like the Lotus leaf is reported. The developed material can reproduce in a controllable and artificial manner the chemical composition and material properties of these natural surfaces. At the same time, the fabrication protocol described here enables realization of properties beyond the ones found in the natural leaves, by allowing facile tuning of the topographical and mechanical properties. The surface topography consists of a micropillar structure assembly with, to the best of the authors' knowledge, the highest to date reported aspect ratio (7.6) for cellulose materials. Additionally, control and tunability of the material's mechanical properties are also demonstrated, which is rendered softer (down to 227 MPa Young's modulus from 997 MPa base value) by adding glycerol as a natural plasticizer. Finally, the self‐cleaning properties are demonstrated and the biodegradability of the material is evaluated in a period of ≈3 months, which confirms full biodegradation. Additionally, water drop and jet impact, and folding tests demonstrate that the material can reasonably sustain its wettability properties. Such a truly bioinspired and biodegradable material system could find potential use in various bioengineering applications.

A pH‐Responsive Biodegradable High‐Strength Hydrogel as Potential Gastric Resident Filler

AbstractIn this study, a pH‐responsive biodegradable high‐strength hydrogel [poly(2‐vinyl‐4,6‐diamino‐1,3,5‐triazine) (PVDT)‐methacrylated gelatin (GelMA)] is synthesized by copolymerization of hydrogen bonding monomer 2‐vinyl‐4,6‐diamino‐1,3,5‐triazine (VDT) and GelMA. The PVDT‐GelMA hydrogel exhibits up to 1.87 MPa tensile stress, 420% breaking strain, 7.24 MPa Young's modulus, and 13.9 MPa compressive strength at 80% strain at pH 7.4, and declines sharply in mechanical performance at pH 1.2 due to the breakup of hydrogen bonding. The strength that the PVDT‐GelMA hydrogel maintains in an acid medium is still superior to that of gastric pressure. This hydrogel can be completely degraded in simulated gastric fluid owing to the synergistic effect of acid swelling and enzymolysis. In a rabbit model experiment, the PVDT‐GelMA hydrogel can reside in the stomach for about 48 h, and no in vivo toxicity is detected in its metabolites, showing an appealing potential as a gastric filler or depot for bariatric interventions and drug delivery.

Production of the biomimetic small diameter blood vessels for cardiovascular tissue engineering

ABSTRACTA novel biomimetic vascular graft scaffolds were produced by electrospinning method with the most superior characteristics to be a proper biomimetic small diameter blood vessel using Polycaprolactone(PCL), Ethyl Cellulose(EC) and Collagen Type-1 were used to create the most convenient synergy of a natural and synthetic polymer to achieve similarity to native small diameter blood vessels. Scanning Electron Microscopy(SEM), Fourier Transform Infrared Spectroscopy(FTIR), Differential Scanning Calorimetry Analysis(DSC), tensile measurement tests, and in-vitro and in-vivo applications were performed. Results indicated significant properties such as having 39.33 nm minimum, 104.98 nm average fiber diameter, 3.2 MPa young modulus and 135% relative cell viability.

Rolled knitted scaffolds based on PLA-pluronic copolymers for anterior cruciate ligament reinforcement: A step by step conception.

The aim of this study was to prepare a new knitted scaffold from PLA-Pluronic block copolymers for anterior cruciate ligament reconstruction. The impact of sterilization methods (beta-ray and gamma-ray sterilization) on copolymers was first evaluated in order to take into account the possible damages due to the sterilization process. Beta-ray radiation did not significantly change mechanical properties in contrast to gamma-ray sterilization. It was shown that ACL cells proliferate onto these copolymers, demonstrating their cytocompatibility. Thirdly, in order to study the influence of shaping on mechanical properties, several shapes were created with copolymers yarns: braids, ropes and linear or rolled knitted scaffolds. The rolled knitted scaffold presented interesting mechanical characteristics, similar to native anterior cruciate ligament (ACL) with a 67 MPa Young's Modulus and a stress at failure of 22.5 MPa. These findings suggest that this three dimensional rolled knitted scaffold meet the mechanical properties of ligament tissues and could be suitable as a scaffold for ligament reconstruction. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 735-743, 2017.

Films made from poly(vinyl alcohol‐co‐ethylene) and soluble biopolymers isolated from postharvest tomato plant

ABSTRACTBlended films were obtained from polyvinyl alcohol‐co‐ethylene (EVOH) with 52 kDa weight average molecular weight (Mw) and three water soluble biopolymers isolated from exhausted tomato plants hydrolysates. Two biopolymers contained mainly polysaccharides and had 27 and 79 kDaMw, respectively. The third contained mainly lignin‐like C moieties and had 392 kDaMW. The films were fabricated with a biopolymer/EVOH w/w ratio ranging from 0.1 to 0.9. All blends had molecular weight and solubility which were substantially different from the starting materials. They were characterized for the chemical nature, and the thermal, rheological, and mechanical properties. Evidence of a chemical reaction between the biopolymers and EVOH was found. Generally, the films exhibited higher mechanical strength but lower strain at break then the neat EVOH. The best performing blended film was fabricated from the 27 kDaMwpolysaccharide. This contained less than 10% biopolymer. It exhibited 1043 MPa Young's modulus and 70% strain at break against 351 MPa modulus and 86% strain for neat EVOH. The results offer scope for investigating biopolymers sourced from other biowastes to understand more the reasons of the observed effects and exploit their full potential to modify or to replace synthetic polymers. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2015,132, 41935.

Edge‐to‐Edge Assembled Graphene Oxide Aerogels with Outstanding Mechanical Performance and Superhigh Chemical Activity

Aerogels, an extremely important aggregation state of various self-assembled nanoscale building blocks, have great potential in fields ranging from energy storage to thermal insulation. However, the porosity of aerogels makes them mechanically weak in most cases, and the chemical activity of the resulting aerogel needs consideration. Herein, chemically crosslinked graphene oxide (GO) 3D aerogels with large specific surface areas (up to 850 m(2) g(-1) ), outstanding mechanical performance (up to 20 MPa Young's modulus, 1 MPa yield strength and 45 J g(-1) specific energy adsorption), and superhigh chemical activity (toward some reducing gases such as H2 S, HI, and SO2 ), are fabricated by assembling 2D GO sheets edge-to-edge into uniform, 3D hydrogel networks with subsequent supercritical fluid drying. These aerogels are superior to other 3D frameworks (e.g. graphene aerogels) assembled via partial overlapping of the basal planes of the 2D building blocks.

Mechanical properties of model ice ridge keels

Abstract Rubble ice presents pressure dependent yield strength and its behaviour can be described by mathematical models based on several mechanical parameters. They are investigated for HSVA model rubble ice through the analysis of three different tests: the oedometer test, the pile test and the punch test. This last test is analysed with the non-linear Eulerian finite element method. The tests were performed on 4 ice ridges with two different submersion times. A 0.5 to 1.2 kPa model scale Mohr–Coulomb cohesion (0.6 to 1.5 kPa Drucker–Prager cohesion), depending on the ridge history, was used in the simulations of the model scale punch tests. The friction angle is estimated between 30 and 45° (40 and 50° Drucker–Prager friction angle). The upper value was used in the punch test simulations. A 0.9 MPa Young modulus was derived and the hydrostatic compressive yield curve was determined. The numerical model is able to estimate the rubble action during the entire penetration of the punch test in the keel and it is shown that a cohesive softening occurs in the rubble. In order to reproduce the experimental load time series for the short submersion time ridges it was necessary to use a vertical distribution of the cohesion representing the vertical distribution of the freeze-bond strength. A sensitivity analysis of the punch test shows that the keel depth and the ice density are the main parameters governing the keel frictional resistance. A precise determination of these parameters is therefore crucial for a correct determination of the rubble mechanical properties from the numerical simulation of experimental punch tests. The punch test is not appropriate for the determination of the friction angle due to the low confinement pressure at the failure plane. The numerical analysis of the punch test allows the estimation of different assumptions used in analytical models for the rubble failure: the cohesion averaging is an under-conservative approximation, and the non-simultaneity of the cohesive and shear resistance maximum values can be considered in the peak load estimation by the computation of their quadratic mean. The comparison with full scale values shows a reasonably good scaling of the cohesion for the model ice ridges with a long submersion time.