Cyclic Compressive Loading Research Articles

The Effectiveness of CFRP- and Auxetic Fabric-Strengthened Brick Masonry under Axial Compression: A Numerical Investigation.

Bonded brickwork used for loadbearing walls is widely found in heritage structures worldwide. The evaluation of bonded masonry structures and their strengthening strategies against dynamic actions require appropriate understanding under cyclic loading. Subsequently, a simplified 3D microscale numerical model is developed in this paper to analyse bonded brickwork under cyclic compression. A plasticity-based damage constitutive model to represent damage in masonry bricks under cyclic compression loading was employed, and zero-thickness interfaces were considered with non-linear damage properties to simulate the mechanical behaviour of masonry. A threshold strain level was used to enact the element deletion technique for initiating brittle crack opening in the masonry units. The developed model was validated against the experimental results published by the authors in the past. The models were able to accurately predict the experimental results with an error limit of 10% maximum. Mainly, two types of strengthening materials, possessing (1) high energy absorption characteristics (auxetic fabric) and (2) high strength properties (carbon fibre reinforced polymer composites/CFRP) were employed for damage mitigation under cyclic compression. Results show that the CFRP-strengthened masonry failure was mainly attributed to de-bonding of the CFRP and crushing under compression. However, the auxetic strengthening is shown to significantly minimise the de-bonding phenomenon. Enhanced energy dissipation characteristics with relatively higher ductility (up to ~50%) and reduced damages on the bonded brickwork were observed as compared to the CFRP-strengthened brickwork under cyclic compression loading. Additionally, the auxetic fabric application also increased the compressive resistance of brickwork by 38–60% under monotonic loading, which is comparably higher than with the CFRP strengthening technique.

Effect of strain rate and load orientation on cyclic response of anisotropic polyurethane foam

Anisotropic cellular materials, such as polymeric foams, play an important role in structures subjected to cyclic loadings. The present paper provides an experimental investigation of the mechanical behavior of an anisotropic polyurethane foam subjected to cyclic compressive loadings under two perpendicular orientations: the rising and perpendicular directions. The foam samples are loaded under three different strain rates and various deformations. The experimental results are presented in terms of elasticity modulus, maximal compressive stress, effective energy absorption capacity, and residual strain. It is proved that the investigated polyurethane foam presents a macroscopic mechanical anisotropy caused by microscopic cell elongation in the foaming direction. Moreover, it is demonstrated that the mechanical behavior of the foam is fully influenced by both deformation rates and imposed strains. The experimental stress–strain curves are modelized using an empirical model considering an adjustable modulus of elasticity. The analytical results show a good agreement with the experiments.

Full and partial compression fatigue tests on welded specimens of steel St 52-3. Effects of the stress ratio on the probabilistic fatigue life estimation

The fatigue strength of structures subjected to cyclic loading depends strongly on the stress ratio. Particularly, in case of welded steel structures this fact is not considered in the corresponding standards nor in the guidelines. Experimentally, two approaches are used to study the effect of stress ratio on the fatigue life. On the one hand, based on the S-Ncurves obtained from tests performed at different stress ratios, the fatigue life under a particular stress range is estimated. On the other hand, the stress amplitude corresponding to a constant fatigue life is estimated by applying the failure criteria for fluctuating stress like the Goodman–Haigh relationship. This paper presents a general probabilistic model, which estimates the S-Nand Goodman–Haigh curves for any stress ratio. Afterwards, this model is applied on data obtained from full and partial cyclic compression loading tests performed on welded specimens made of steel St 52-3. The tested details correspond to the permissible notch condition limit occurred in highly stressed structures used to build ships.

Biomechanical Comparison of Use of Two Screws versus Three Screws Per Fragment with Locking Plate Constructs under Cyclic Loading in Compression in a Fracture Gap Model

Abstract Objectives The aim of this study was to measure and compare the stiffness and cyclic fatigue of two plate-bone model constructs, with either two or three locking screws per fragment, under cyclic compression. Methods A 10-hole 3.5 mm stainless steel locking compression plate (LCP) was fixed 1 mm from a synthetic bone model in which the fracture gap was 47 mm. Two groups of 10 constructs, prepared with either two or three bicortical locking screws placed at the extremities of each fragment, were tested in a load-controlled compression test until failure. Results The three-screw constructs were stiffer than the two-screw constructs (196.75 ± 50.48 N/mm and 102.43 ± 22.93 N/mm, respectively) and the actuator displacements of the two-screw constructs were higher (18.02 ± 1.07 mm) than those of the three-screw constructs (14.48 ± 2.25 mm). The number of cycles to failure of the two-screw constructs was significantly lower (38,337.50 ± 2,196.98) than the that of the three-screw constructs (44,224.00 ± 1,515.24). Load at irreversible deformation was significantly lower in the two-screw constructs (140.93 ± 13.39 N) than in the three-screw constructs (184.27 ± 13.17 N). All constructs failed by plate bending at the gap between the two cylinders. Clinical Significance Omission of the third innermost locking screw during bridging osteosynthesis subjected to compression forces led to a 13.3% reduction in the number of cycles to failure and a 23.5% reduction of the load withstood by the plate before plastic deformation occurred.

The Ability of Two Chewing Simulation Devices in Emulating the Clinical Deterioration of Anterior Composite Restorations in Severely Worn Teeth.

This study investigated the ability of two chewing simulation devices to emulate in vitro the clinical deterioration observed in anterior composite restorations in severe tooth-wear patients. Advanced tooth wear was simulated in bovine incisors, which were restored with palatal and buccal direct composite veneer restorations. The incisal edges of restorations were subjected to 960K cycles of either compressive loading (Biocycle-V2; 125 N at 2 Hz) or wear and mechanical loading (Rub and Roll; 30 N at 20 rpm). Surface degradation was rated using FDI scores to compare the chewing devices (Fisher's test, a = 0.05). Topography and deterioration of restorations was analyzed using SEM. The ability to emulate the deterioration was investigated by comparing the surface degradation observed in vitro with the clinical degradation observed in restorations placed in severe tooth-wear patients after 3.5 years. Distinct degradation patterns were observed between the simulation devices: Biocycle-V2 generated deterioration that was not comparable to the clinical situation, including contact damage, minor wear, and localized roughening. The degradation caused by Rub and Roll was more similar to the in vivo situation, including wear facets, chipping, delamination, staining, and marginal ditching. The FDI scores were different between the chewing devices for surface/marginal staining, material/retention, and marginal adaptation (p = 0.003). SEM analysis showed microcracking at the interface between composite layers at the incisal edges. The Rub and Roll chewing device was able to emulate the clinical deterioration observed in anterior restorations in severe tooth-wear patients and thus may be used as an oral-cavity simulation method, contributing to translational research.

Investigation on mechanical behaviors of a new sustainable composite material for fiber-reinforced recycled aggregate concrete under compressive low-cycle loadings

Recycled aggregate concrete (RAC) has been attracting worldwide research and development interests due to its ecological and economic significance. In this investigation, the steel fiber (SF) and polypropylene fiber (PPF) were mixed into the recycled aggregate concrete (RAC) to improve the mechanical properties. Based on the cyclic compressive loading tests, the variation of the strength and deformation of fiber-reinforced recycled aggregate concrete (FRAC) was explored, and the optimum design method of fiber content for FRAC was proposed. The calculation models for fiber influence factors (FIFs) of the peak stress, peak strain, ultimate strain, and the post-peak modulus were put forward, respectively. The optimum volume fractions of SF and PPF for RAC were recommended, which are 1.7% and 2.27%, respectively. This study provides technical support and a theoretical basis for the promotion of recycled aggregate concrete material and structure.

Low-cycle fatigue assessment of open-cell A332 aluminum alloy foams

Though metal foams are used in applications where they could be exposed to cyclic loading, their fatigue strengths also must be evaluated concerning this fact that these materials have much lower resistance to cyclic loads than their base bulk materials. In this study, the open cell foam specimens which are produced by A332 aluminum alloy stir casting and solidification under pressure, are subjected to force-controlled cyclic compressive loading. Experiments revealed that the produced foams have a good capacity for fatigue loading so that in the range of stress range below 90% of corresponding yield stress, almost no low-cycle fatigue occurs.

Damage evolution in cross-ply laminates under tension–compression and compression-compression cyclic loads

Tension-Compression and Compression-Compression fatigue tests were carried out on glass/epoxy cross-ply laminates, with different values of the minimum to maximum load ratio R (−1, −3, −5, −7, −10 and 20). During the tests, the damage evolution in the 90° ply was monitored at the macro-and micro-scales. Three damage scenarios were observed, depending on the load ratio: i) initiation and propagation of transverse cracks for R ≥ −3, ii) initiation of multiple inclined short cracks for R = 20, iii) a mixed damage type with the presence of both transverse cracks and inclined short cracks for −10 ≤ R ≤ −5. Finite Element analyses of micro-scale Representative Volume Elements, combined with a recently developed crack initiation criterion, revealed the role of the Local Hydrostatic Stress in the matrix in controlling the different damage scenarios. Eventually, quantitative analyses showed a highly detrimental effect of the compressive part of the cycle on the transverse crack initiation and propagation.

Multi-scale Crystal Viscoplasticity Approach for Estimating Anisotropic Steady-State Creep Properties of Single-Crystal SnAgCu Alloys

Creep can have a significant impact on the reliability of Sn-based solder alloys even at room temperature because of their relatively low melting temperatures. SnAgCu (SAC) solder joints used in electronic packaging typically consist of only a few highly anisotropic grains, which consist of Sn dendrites embedded in a near-eutectic Sn-Ag component. The unique grain structure of each joint leads to stochastic variations in the thermomechanical response of such joint. Therefore, grain-scale testing and modeling are recommended to better characterize the anisotropic behavior and to estimate the influence of stochastic variability of grain structure on the viscoplastic response of the joint. This work aims to investigate the anisotropic steady-state creep behavior of single-crystal SAC solder joints. The orientation-dependent viscoplastic behavior of individual SAC grains is modeled with a multi-scale crystal-viscoplasticity approach for representing the relevant dislocation mechanics. The response predicted by the crystal viscoplasticity model is then captured in an equivalent homogenized continuous-scale constitutive model (Hill-Garofalo formulation).This modeling strategy was implemented in numerical simulations, as an illustrative example, to analyze the behavior of single-grain solder joints subjected to combined steady compression (from heat-sink clamping force) and thermal cyclic loading. The cyclic ratcheting in the presence of the steady compressive force causes: (i) transverse expansion of the solder ball, potentially leading to eventual short circuits; and (ii) cyclic fatigue damage leading to eventual failure of the solder joint. The proposed grain-scale modeling approach is shown to be able to address the stochastic variability of both these damage mechanisms, as a function of grain orientation. The present methodology can be used to predict the realistic behavior of solder joints, based on their microstructure, and provide valuable insights for their reliability analysis.

A phase-dependent constitutive model to predict cyclic electrical conductivity in fuel cell gas diffusion media

Structure-property relation in fuel cell gas diffusion layer (GDL) is a dependent function of its constituents. The bulk electrical conductivity of these layers is known to be relative density function varying due to external force or cell operating conditions. To locally predict the changes due to complex working conditions, an accurate model that predicts the nonlinearity of GDLs is highly desirable. To this end, this article proposes a material model that is phenomenologically derived to address the cyclic electrical conductivity of GDLs. Functional variables are taken to operate on porosity variation, fiber contact density, and fiber dislocation parameters. In the presence of these parameters, the results illustrate nonlinear conductivity variation with the magnitude of applied cyclic compressive load. Through successive loading-unloading, the porous structure is modeled to reach a steady-state reflecting stable conductivity-stress behavior for the constant stress limit. An interesting behavior of GDL can be captured where conductivity reduces as compressive load exceeds a threshold limit called break stress due to fiber breakages or dislocations. A greater applicability of this model may lie in mapping localized in-situ response of GDLs under cyclic operations.

Compression Behavior of EBM Printed Auxetic Chiral Structures.

In this study, the cyclic compression and crush behavior of chiral auxetic lattice structures produced from titanium alloy (Ti6Al4V) metallic powder using electron beam melting (EBM) additive manufacturing technology is investigated numerically and experimentally. For material characterization and understanding the material behavior of EBM printed parts, tensile and three-point flexural tests were conducted. Log signals produced during the EBM process were investigated to confirm the stability of process and the health of the produced parts. Furthermore, a compressive cyclic load profile was applied to the EBM printed chiral units having two different thicknesses to track their Poisson’s ratios and displacement limits under large displacements in the absence of degradation, permanent deformations and failures. Chiral units were also crushed to investigate the effect of failure and deformation mechanisms on the energy absorption characteristics. Moreover, a surface roughness study was conducted due to high surface roughness of EBM printed parts, and an equation is offered to define load-carrying effective areas to prevent misleading cross-section measurements. In compliance with the equation and tensile test results, a constitutive equation was formed and used after a selection and calibration process to verify the numerical model for optimum topology design and mechanical performance forecasting using a non-linear computational model with failure analysis. As a result, the cyclic compression and crush numerical analyses of EBM printed Ti6Al4V chiral cells were validated with the experimental results. It was shown that the constitutive equation of EBM printed as-built parts was extracted accurately considering the build orientation and surface roughness profile. Besides, the cyclic compressive and crush behavior of chiral units were investigated. The regions of the chiral units prone to prematurely fail under crush loads were determined, and deformation modes were investigated to increase the energy absorption abilities.

The effect of corrosion on the hysteresis properties of welded steel

ABSTRACT To study the effect of corrosion on the mechanical properties of welded steel hysteresis, a cyclic load test was performed on corroded welded steel. Accordingly, a generalised hysteretic mechanical model of welded steel with the corrosion degree as a variable was established. Taking a D36 steel plate fabricated via manual arc welding as the research object, specimens were prepared using the accelerated electrochemical corrosion method. Mechanical performance experiments under tension, compression, and multiple cyclic loading systems were conducted on specimens, the hysteretic mechanical properties of welded steel were mostly concerned. On that base, a generalised hysteretic material model for welded-corroded steel which consists of a skeleton curve, an unloading curve and a reloading curve is proposed. All the parameters used to describe these curves are related to the degree of corrosion, determined by the regression on the test data. The accuracy and effectiveness of the model were verified experimentally.

Piezoresistive 3D graphene–PDMS spongy pressure sensors for IoT enabled wearables and smart products

Recently, 3D porous graphene–polymer composite-based piezoresistive sensors have gained significant traction in the field of flexible electronics owing to their ultralightweight nature, high compressability, robustness, and excellent electromechanical properties. In this work, we present an improved facile recipe for developing repeatable, reliable, and linear 3D graphene–polydimethylsiloxane (PDMS) spongy sensors for internet of things (IoT)-enabled wearable systems and smart consumer products. Fundamental morphological characterization and sensing performance assessment of the piezoresistive 3D graphene–polymer sensor were conducted to establish its suitability for the development of squeezable, flexible, and skin-mountable human motion sensors. The density and porosity of the sponges were determined to be 250 mg cm−3 and 74% respectively. Mechanical compressive loading tests conducted on the sensors revealed an average elastic modulus as low as ∼56.7 kPa. Dynamic compressive force-resistance change response tests conducted on four identical sensors revealed a linear piezoresistive response (in the compressive load range 0.42–2.18 N) with an average force sensitivity of 0.3470 ± 0.0794 N−1. In addition, an accelerated lifetime test comprising 1500 compressive loading cycles (at 3.90 N uniaxial compressive loading) was conducted to demonstrate the long-term reliability and stability of the sensor. To test the applicability of the sensors in smart wearables, four identical graphene–PDMS sponges were configured on the fingertip regions of a soft nitrile glove to develop a pressure sensing smart glove for real-time haptic pressure monitoring. Similarly, the sensors were also integrated into the Philips 9000 series electric shaver to realize smart shaving applications with the ability to monitor shaving motions. Furthermore, the readiness of our system for next-generation IoT-enabled applications was demonstrated by integrating the smart glove with an embedded system software utilizing the an open source microcontroller platform. The system was capable of identifying real-time qualitative pressure distribution across the fingertips while grasping daily life objects, thus establishing the suitability of such sensors for next-generation wearables for prosthetics, consumer devices, and personalized healthcare monitoring devices.

Hysteretic deteriorating behaviors of fiber-reinforced recycled aggregate concrete composites subjected to cyclic compressive loadings

An intensive test is designed to investigate the reinforcing mechanism of fibers, stress-strain relationship, and damage evolution of fiber-reinforced recycled aggregate concrete (FRAC). Hooked-end steel fiber (SF) and polypropylene fiber (PPF) are used, and four volume fractions of 0, 0.968%, 1.653%, and 2.338% are considered. The hysteretic deteriorating properties of FRAC under cyclic loadings are revealed, and the fracture interface inclination model is suggested accounting for the fiber content. The stress process and fiber reinforcing mechanism under cyclic loadings are explored. The toughness of FRAC depends strongly on the fiber reinforcing parameter. When the steel/PP fiber volume ratio reaches 1.653%, the toughness indexes of SF-reinforced RAC and PPF-reinforced RAC are increased by 88% and 80%, respectively. The function model for the toughness index of FRAC accounting for the fiber content is proposed. In the pre-peak load stage, the damage modulus decreases slowly because the residual strain is very small. However, in the post-peak loading stage, the damage modulus decreases continuously with the increase of residual strain. The residual strain is related closely to the degradation of the damaged modulus. A new degradation model represented by residual strain is suggested accounting for the fiber content.

Effects of aging on the stress-induced martensitic transformation and cyclic superelastic properties in Co-Ni-Ga shape memory alloy single crystals under compression

Co-Ni-Ga shape memory alloys attracted scientific attention as promising candidate materials for damping applications at elevated temperatures, owing to excellent superelastic properties featuring a fully reversible stress-strain response up to temperatures as high as 500 °C. In the present work, the effect of aging treatments conducted in a wide range of aging temperatures and times, i.e. at 300–400 °C for 0.25–8.5 h, was investigated. It is shown that critical features of the martensitic transformation are strongly affected by the heat treatments. In particular, the formation of densely dispersed γ’-nanoparticles has a strong influence on the martensite variant selection and the morphology of martensite during stress-induced martensitic transformation. Relatively large, elongated particles promote irreversibility. In contrast, small spheroidal particles are associated with excellent functional stability during cyclic compression loading of 〈001〉-oriented single crystals. In addition to mechanical experiments, a detailed microstructural analysis was performed using in situ optical microscopy and neutron diffraction. Fundamental differences in microstructural evolution between various material states are documented and the relations between thermal treatment, microstructure and functional properties are explored and rationalized.

Analysis of Damage Evolution in Concrete under Fatigue Loading by Acoustic Emission and Ultrasonic Testing.

The fatigue process of concrete under compressive cyclic loading is still not completely explored. The corresponding damage processes within the material structure are especially not entirely investigated. The application of acoustic measurement methods enables a better insight into the processes of the fatigue in concrete. Normal strength concrete was investigated under compressive cyclic loading with regard to the fatigue process by using acoustic methods in combination with other nondestructive measurement methods. Acoustic emission and ultrasonic signal measurements were applied together with measurements of strains, elastic modulus, and static strength. It was possible to determine the anisotropic character of the fatigue damage caused by uniaxial loading based on the ultrasonic measurements. Furthermore, it was observed that the fatigue damage seems to consist not exclusively of load parallel oriented crack structures. Rather, crack structures perpendicular to the load as well as local compacting are likely components of the fatigue damage. Additionally, the ultrasonic velocity appears to be a good indicator for fatigue damage beside the elastic modulus. It can be concluded that acoustic methods allow an observation of the fatigue process in concrete and a better understanding, especially in combination with further measurement methods.

Design of smart cementitious composites based on multi-walled carbon nanotubes (MWCNTs) using probe ultrasonicator for dispersion

The purpose of this study is to develop smart cementitious material by incorporating multi-walled carbon nanotubes (MWCNTs). Two different types of carbon nanotubes (CNT) were dispersed using probe ultrasonicator; (i) Pristine CNT (P-CNT), and (ii) Functionalized CNT through annealing (A-CNT). Percolation threshold and optimum content of CNTs were determined by measuring electrical resistivity, porosity, compressive and flexural strengths at various contents of CNTs (0, 0.5 %, 0.75 %, and 1 % with respect to mass of cement). Self-sensing study was also carried out on smart material by relating the electrical properties with cyclic compressive loading. For this purpose, the electrical response was recorded with Wheatstone Bridge (WSB) circuit. The effect of curing and saturation degree of specimens on the resistivity pattern was also discussed. The results of electrical resistivity and mechanical properties showed that the content of CNTs should be at least 0.75 % to develop smart cementitious materials with a significant sensitivity and without detrimental effect on the mechanical properties. Moreover, smart material incorporating pristine CNT provides better sensitivity of self-sensing response as compared to the annealed CNT. Self-sensing test results also showed that with the increase in the content of CNT, sensitivity and repeatability of the sensing response were improved.

Cementitious composites incorporating Multi-Walled Carbon Nanotubes (MWCNTs): effects of annealing and other dispersion methods on the electrical and mechanical properties

This study focuses on different techniques for dispersing Multi-Walled Carbon Nanotubes (MWCNTs) in cementitious materials. The impact of dispersion is observed through electrical resistivity and mechanical properties of cementitious composites. Two contents (0.5 and 1% by mass of cement) of MWCNTs are investigated and three different techniques were used to disperse CNTs in water by sonication: (i) pristine, P-CNT, (ii) functionalized carbon nanotubes by classical approach (dispersive agent, D-CNT), and (iii) by an innovative approach (annealing, A-CNT). Self-sensing response of the material under cyclic compressive loading is measured with Wheatstone Bridge (WSB) circuit. Results showed a detrimental effect of dispersive agent on the resistivity and mechanical properties of cementitious composites irrespective of the content of CNTs. However, the impact of P-CNT and A-CNT on the reduction of mechanical properties is slight. With the use of 1% content of A-CNTs, a stable resistivity response of the material is observed irrespective of the saturation degree. This indicates that content higher than 1% of A-CNTs is not required for the development of smart cementitious composites for structural health monitoring (SHM). The test results of self sensing measurements indicate a poor repeatability of the electrical response for plain mortar under each loading cycle while, stable response is noticed with specimens incorporating 1% of A-CNTs. The maximum variation in fractional change in voltage (FCV) shown by plain mortar is 6.3% indicating high electrical resistance of plain mortar, while in case of mortar containing 1% A-CNTs, variation in FCV is 35% indicating lower electrical resistance and better sensitivity of the material.

P6 - Deterioration of composite restorations in tooth wear patients: translational approach

This study investigated the clinical deterioration of anterior resin composite restorations placed in tooth wear patients after 36 months and later compared the ability of two chewing simulation devices in emulating in vitro the clinical deterioration observed in those restorations. For the clinical observation, 270 anterior maxillary resin composite restorations in 47 patients were evaluated after 36 months of clinical service by using intraoral photographs and 3D scans to rate modified FDI scores and investigate the presence of degradation features. Multivariable logistic regression models were used to analyze the clinical data (p<0.05). For the in vitro approach, tooth wear was simulated in bovine incisors, which were restored with materials and techniques similar to those in the clinical observation. Incisal edges of the restorations were subjected to 960,000 cycles of either compressive loading (Biocycle-V2; 125 N; 2 Hz) or wear and mechanical loading (Rub&Roll; 30 N; 20 rpm). Surface degradation was rated using the modified FDI scores to compare the chewing devices (Fisher’s test, ?=0.05). In the clinical observation, early degradation signs were present at 1 month: irregularities (41.5%) and ditching (7.4%) were observed at the surface and adhesive interfaces. The frequency of irregularities decreased in the 36-month follow up (37%), but ditching (12.2%) and fractures (10.7%) were more common. After 36 months, the most frequent esthetic deterioration was noticeable for staining (44%) and loss of luster (31%). For functional deterioration, in the 3D scans, wear (25%), marginal adaptation (24%), and surface irregularities (19%) were the most frequent forms. The simulation devices produced distinct degradation patterns: Biocycle-V2 generated deterioration not comparable to the clinical situation, including contact damage, minor wear, and localized roughening. The degradation caused by Rub&Roll was more similar to the in vivo situation, including wear facets, chipping, delamination, staining, and marginal ditching. The FDI scores differed between the chewing devices for staining, material/retention, and marginal adaptation (p?0.003). The clinical observation revealed a continuous deterioration process in tooth wear patients with a progression of the deterioration until 36 months. The laboratory simulation of the deterioration showed that the Rub&Roll chewing device could emulate the clinical deterioration observed in anterior restorations in tooth wear patients and could be used as a mouth simulation method, contributing to translational research.

Preliminary mechanical evaluation of two novel veterinary angle-stable-threaded interlocking nail systems

ABSTRACT: The interlocking nail represents an excellent option as a surgical approach to treat fractures in long bones in veterinary medicine. However, failures were reported mainly due to a slack present in the interface of the rod with the screws. The present study tested and mechanically compare axial compression loads of two novel models of stable angle interlocking nails with threaded holes. Among the two models, one was uniplanar and the other was multiplanar with orthogonally arranged distal holes. Twenty-one specimens made of polylactic acid were used for the implantation of interlocking nail´s rods, divided into three groups: conventional interlocking nail (G1), novel interlocking nail with a stable angle with holes arranged in a single plane (G2), and novel interlocking nail with a stable angle in two planes, with the penultimate hole at 90 degrees from the others (G3). Biomechanical tests were performed using axial, cyclic, and destructive compression load for comparison between them. All the specimens showed plastic deformation in the screws after destructive tests, in both proximal and distal sides, being highly intense in G1. G2 and G3 of the stable angle rods supported higher loads than G1 in all tests performed (P&lt;0.05). The novel stems did not differ statistically from each other (P&gt;0.05). The initial hypothesis that the novel models would provide increased stability was confirmed; however, no differences were demonstrated between them. The screw locking system on the rods allowed high resistance values in the tests performed, proving to be effective and potentially applicable in real clinical situations.