Quasi-static Four-point Bending Research Articles

Blast retrofit of shear-deficient high-strength concrete beams with ultra-high performance concrete

This research has investigated the ability of ultra-high performance concrete (UHPC) to improve the blast performance of high-strength concrete (HSC) beams. As part of the study 4 shear-deficient HSC beams built without stirrups and with dimensions of 125 mm × 250 mm × 2440 mm were retrofitted with a UHPC jacket and tested under simulated blast loads using a shock-tube. The retrofit involved replacing the existing cover with a cast in-situ UHPC jacket (with thickness of 20–40 mm). A companion set of beams was also tested under quasi-static four-point bending. The results from the blast and static tests are compared to a control set of HSC beams built without and with stirrups to examine the ability of UHPC to increase shear and flexural resistance, respectively. The effect of steel ratio (ρ = 1.6% or 2.4%), an important parameter which affects the behavior of HSC and UHPC beams, was also investigated in beams with 15M and 20M bars. Under static loading, the results show that the UHPC jacket was able to prevent shear failure, and improve flexural performance by increasing strength by 40–125%, stiffness by 80–100% and overall toughness by 56–144%, when compared to the companion HSC beams. Under blast loading, the UHPC increased shear capacity, prevented shear failure and improved blast performance by reducing displacements, increasing overall blast capacity and improving damage tolerance. For example, in the 20M set, the UHPC-retrofitted beam showed reductions of 26–63% in maximum displacements, and 88–100% in residual displacements under varying blast intensities. The steel ratio was found to play an important role on the failure mode of the retrofitted beams under static loading, with bar fracture observed in the beam with lower steel ratio of 1.6%. As part of the numerical study, the blast response of the UHPC retrofitted beams was predicted using 3D finite element (FE) modeling. The FE models were able to predict the failure modes and maximum displacements of the control and UHPC retrofitted beams, with an average numerical-to-experimental displacement ratio of 1.03 and an average error of 8%.

A physically based strength prediction model for glass

The strength of glass has been a subject of great interest for more than one hundred years. Due to the stochastic nature of glass, governed by microscopical surface flaws, glass plates exhibit large variations in fracture strength. The aim of this work is to propose a new strength prediction model for glass, named the Glass Strength Prediction Model (GSPM) that captures the nature of fracture initiation in glass, spanning from rate dependence to size effects. We aim for the presented model to be applicable in modern design processes and provide a procedure to facilitate input parameter calibration for glass plates from different suppliers. GSPM is a Monte-Carlo based model that combines the theories of linear elastic fracture mechanics (LEFM) and sub-critical crack growth (SCG) to generate virtual tests on a representative sample of glass plates. The stress evolution in the glass plates is obtained from finite element (FE) simulations. The model results in representative fracture strength distributions that span the probable fracture initiation instances with respect to time, location and stress level. We also demonstrate how the GSPM can be used to trigger fracture in constitutive models applied in FE simulations. This feature provides the option to investigate scenarios including multiple glass plates with interdependent fracture initiation behavior. The GSPM displays great promise in terms of usability and prediction capacity. It is able to capture the fracture initiation behavior of glass plates of varying geometries exposed to load cases spanning from, e.g., quasi-static four-point bending to blast pressure. The model has the potential to reduce the number of physical experiments and numerical FE simulations in modern development processes of glass structures.

Influence of UHPFRC jacketing on the static, blast and post-blast behaviour of doubly-reinforced concrete beams

This paper investigates the effects of ultra-high performance fiber-reinforced concrete (UHPFRC) jacketing on the static and blast behavior of reinforced beams. The test program included a total of six beams with dimensions of 150 mm × 200 mm × 2440 mm, including three replicate control beams, and three replicate beams retrofitted with a 20 mm UHPFRC jacket. The beams were doubly-reinforced, with provision of compression bars and ties spaced at 75 mm throughout the beam span. Each beam type included specimens tested under quasi-static four-point bending, and repeated or singly-applied blast loads applied using a shock-tube. Under static loading the UHPFRC is shown to increase beam stiffness and capacity, however the high bond capacity of the UHPFRC, crack localization effect, and relatively low steel ratio resulted in bar rupture, thereby reducing ductility. Under repeated blast loading the UHPFRC effectively reduced maximum and residual displacements at equivalent blasts, but the crack localization which initiated at the earlier blasts eventually led to bar rupture. Under the singly-applied blast, the UHPFRC was found to reduce displacements, and better control damage when compared to the companion RC beam, without bar rupture. As part of the numerical study, finite element (FE) modelling was used to predict the blast response and damage in the test beams. A parametric study is also used to examine the effects of steel ratio, jacket thickness and jacket interface location on blast behavior.

A novel profiling concept leading to a significant increase in the mechanical performance of metal to composite adhesive joints

Traditional adhesive joints with straight edged adherends suffer from a significant stress concentration in the composite coincident with the edge of the metal adherend, which can lead to accelerated translaminar failure of the substrate. In this work, we developed a novel profiling concept which improves the mechanical performance of adhesive joints between metallic adherends and composite substrates. We conducted quasi-static four-point bending (4PB) tests which showed that profiling the edge of the metallic adherend could improve the peak load by at least 27%, and that the stability of failure was simultaneously improved. We investigated varying the profile parameters and were able to conclude that further significant mechanical performance gains could be achieved by increasing any of the profile: amplitude, frequency, or number of fractal length-scales. By analysing in-situ acoustic emission (AE) monitoring data we were able to observe that profiling of the metallic adherend results in failure initiation occurring at higher loads, which suggests that the concept is successful in providing better stress distributions and lowering peak stresses. By analysing the fracture surfaces, it is apparent that the profiling concept is successful in deflecting the translaminar fracture path; and additionally that a debonding mechanism occurs at the profile tips which is thought to be an important additional mechanism for creating damage tolerant joints.

Multimodal NDT monitoring of TRC sandwich under bending and early detection of interlaminar debonding

Textile Reinforced Cementitious (TRC) sandwich composites provide a load-bearing, noncorrosive, lightweight, and durable alternative for steel-reinforced sandwich elements, and/or traditional steel-reinforced concrete. However, the composite nature of the material and slender nature of the facings render the fracture behavior complex. Insufficient interlaminar bond can cause premature debonding, substantially reducing the loadbearing capacity of the composite. Non-Destructive Testing (NDT) techniques seem the obvious choice to monitor the damage progression of the material without affecting, nor compromising the behavior of the composite, and predict their service life. In this study, TRC sandwich composites, subjected to quasistatic four-point bending, are monitored with three NDTs. Digital Image Correlation (DIC) allows to measure the surface strains and displacements. MMW Spectrometry, used for the first time in bending damage monitoring, allowed to detect damage such as cracking, or debonding, while Acoustic Emission (AE) allowed to localize and characterize internal cracking. In order to simulate premature debonding, the bond between the tensile TRC facing and the insulation, in the central zone, where the bending moment is maximum, was artificially destroyed. Results show that a weak interlaminar bond reduced the ultimate load of the composite by more than 50%. Additionally, DIC, AE and MMW Spectrometry proved useful to monitor and characterize damage. Multimodal data gathered from the multimodal NDTs showed to be complementary. DIC allowed to interpret AE and MMW Spectrometry data from a surface viewpoint, while AE parameters permit predictions at low load conditions, and detect internal cracking. For instance, the AE behavior at early load stage (less than 15% of the maximum load) of the TRC sandwich with destroyed bond showed significant differences than for the reference TRC sandwich. Specifically, it showed higher RA values, and lower AF than the reference TRC sandwich, suggesting more shear related early activity for, promoted by the damaged bond. Results were corroborated with DIC, while MMW Spectrometry seemed to follow closely the level of damage of TRC sandwich composites under quasi-static four-point bending. EWGAE 35, Ljubljana, Slovenia, 13th – 16th Sep. www.ewg

Damage evolution detection in a pipeline segment under bending by means of acoustic emission

A steel pipeline segment of 2.5 m length was subjected to quasi-static four-point bending load in three steps for studying the initial cracking and damage accumulation based on the Acoustic Emission (AE) technique and by the direct current potential drop (DCPD) technique. For the latter, a new post-test analysis method was established. AE is found more sensitive to crack initiation than DCPD. Formation of mesoscopic and macroscopic cracks as well as their closure and the resulting friction generate weighted peak frequencies below 400 kHz, whereas microscopic cracking produces AE with broad band spectra identifiable by weighted peak frequencies above 400 kHz. Critical states alike the maximum load level and the leak opening were accompanied by peak amplitudes above 85 dBAE. This rather fundamental study provides a data base for possibly developing advanced strategies of detection and alarm systems based on acoustic monitoring of pipelines, or at least, steel structures.

Laminated Glass Plates Subjected to High-Velocity Projectile Impact and Their Residual Post-Impact Performance

This study aims to analyze the performance of laminated glass against ballistic loading and investigates its residual load-bearing capacity. Two groups of specimens were used in quasi-static four-point bending experiments, first without prior ballistic damage and then with it. The main objective was to compare the load-bearing capacity of these two groups to see the effect of ballistic damage. Three different layer compositions were used. The ballistic loading was conducted using an in-service 9 mm bullet fired from a semiautomatic carbine with the glass specimens hanging on steel ropes in a free boundary setup. Numerical simulation and analytical methods were used and validated against the measured response of the undamaged specimens. The simulations were in good agreement with the experimental results. All of the glass specimens were able to withstand the ballistic loading, and the subsequent performance during the quasi-static bending loading was similar to that of the undamaged specimens. The quality of the glass edges seemed to be more important than ballistic damage. The front-plate damage played a negligible role, and the back-plate damage needed to be extensive to influence subsequent performance. Provided that ballistic damage is mainly localized only to the centers of the plates, it did not affect the post-impact loading capacity.

Impact and quasi-static bending tests for a novel composite structure of ceramic and polymeric matrix composites

To resolve the dilemma between impact resistance and structural stiffness of fan containment casing of modern civil aeroengines, a novel composite structure (CS) is proposed. It combines the hard and stiff ceramic which layered at the impact side and the lightweight and tough polymeric matrix composites (PMC) on the back side. The new structure was tested under ballistic impact loadings and quasi-static four-point bending. The results indicate that the impact resistance of the new structure is improved, compared with the PMC-only samples. Meanwhile, the bending stiffness of the new structure is also substantially larger at the cost of much lower bending strength.

Experimental and numerical investigations on a novel plate anchorage system to solve FRP debonding problem in the strengthened RC beams

Method of externally bonded reinforcement (EBR) is one of the most prominent systems for retrofitting reinforced concrete (RC) beams containing fiber-reinforced polymers (FRP). Many studies conducted in this field confirm the fact that the majority of the beams strengthened in this way experience failure due to the sudden detachment of FRP sheets from the concrete substrate. In this regard, an innovative plate anchorage technique was presented to solve the FRP debonding problem. In this method (EBR by Welded Steel Plates), two plates are placed near the beam supports, which are connected by welding to a longitudinal tension reinforcement through the angles. FRP sheets are placed on seat plates at both ends and fixed in their position by another plate placed over them. Ten RC beams with 150 × 200 × 2000 mm were prepared from concrete in 21 and 35 MPa strength classes. All specimens were subjected to a quasi-static four-point bending test. A comparative study was also done using an analytical method and comparing experimental results in the literature. This research results revealed that the better and more practical performance of the suggested plate anchorage system resulted in postponing or completely solving the FRP surface debonding problem.

IN VITRO MECHANICAL EVALUATION OF SPINAL FIXATION ROD CONNECTORS

ABSTRACT Objective Evaluate and compare the mechanical resistance and the fatigue behavior associated with the use of three different modalities of vertebral fixation system rod connectors through in vitro pre-clinical mechanical tests developed specifically for this application (linear, lateral with square connector and lateral with oblique connector). Methods Cobalt chromium rods 5.5 mm in diameter were used and coupled with three types of connectors: a) side rod with oblique connector, b) side rod with square connector, and c) rod and linear connectors. Quasi-static mechanical four-point bending and fatigue tests were performed. The variables measured were (I) the bending moment at the yield limit, (II) the displacement at the yield limit, (III) the rigidity of the system in flexion and (IV) the number of cycles until system failure. Results The linear system presented the greatest force and the greatest moment at the yield limit, as well as the greatest stiffness equivalent to bending. All specimens with square and oblique connectors endured 2.5 million cycles in the minimum and maximum conditions of applied moment. The specimens with linear connector endured 2.5 million cycles with fractions of 40.14% of the bending moment at the yield limit, but failed with levels of 60.17% and 80.27%. Conclusions Systems with linear connectors showed greater mechanical resistance when compared to systems with square and oblique connectors. All systems supported cyclic loads that mimic in vivo demands. Level of evidence V; In vitro research.

Bending strength of ceramic compounds bonded with silicate-based glass solder

AbstractIn the field of dental technology, the length of ceramic pontics is limited to avoid mechanical failure. To reduce thermal-induced residual stress within the ceramic, using smaller subcomponents and subsequent bonding with silicate-based glass solder may be a favorable approach. Thus, the bending strength of zirconia compounds bonded with different silicate-based glass solders was investigated. For this purpose, rectangular specimens made of zirconia were bonded by glass solder. Parameters such as the scarf angle (45° and 90°), two different glass solders, as well as the soldering process (pressure and surface treatment) were varied. All specimens were subjected to quasi-static four-point bending tests according to DIN EN ISO 843-1. Additionally, the quality of the glass solder connection was evaluated usingμCT and fractography. In the present study, zirconia compounds were sucessful bonded of zirconia compounds using silicate-based glass solder was. No significant differences in terms of bending strength were observed with respect to the different bonding parameters analyzed. The highest bending strength of 130.6 ± 50.5 MPa was achieved with a 90° scarf angle combined with ethanol treatment of the specimens before soldering and an additional application of a pressure of 2 bars in a dental pressure pot before subsequent soldering. Nevertheless, the bending strengths were highly decreased when compared to monolithic zirconia specimens (993.4 ± 125.5 MPa).

Immersion in Raloxifene does not significantly improve bone toughness or screw pull-out strength in multiple in vitro models

BackgroundFailure of surgical fixation in orthopaedic fractures occurs at a significantly higher rate in osteoporotic patients due to weakened osteoporotic bone. A therapy to acutely improve the mechanical properties of bone during fracture repair would have profound clinical impact. A previous study has demonstrated an increase in mechanical properties of acellular cortical canine bone after immersion in raloxifene. The goal of this study was to determine if similar treatment yields the same results in cancellous fetal bovine bone and whether this translates into a difference in screw pull-out strength in human cadaveric tissue.MethodsCancellous bone from fetal bovine distal femora underwent quasi-static four-point bending tests after being immersed in either raloxifene (20 μM) or phosphate-buffered saline as a control for 7 days (n = 10). Separately, 5 matched pairs of human osteoporotic cadaveric humeral heads underwent the same procedure. Five 3.5 mm unicortical cancellous screws were then inserted at standard surgical fixation locations to a depth of 30 mm and quasi-static screw pull-out tests were performed.ResultsIn the four-point bending tests, there were no significant differences between the raloxifene and control groups for any of the mechanical properties - including stiffness (p = 0.333) and toughness (p = 0.546). In the screw pull-out tests, the raloxifene soaked samples and control samples had pullout strengths of 122 ± 74.3 N and 89.5 ± 63.8 N, respectively.ConclusionsResults from this study indicate that cancellous fetal bovine samples did not demonstrate an increase in toughness with raloxifene treatment, which is in contrast to previously published data that studied canine cortical bone. In vivo experiments are likely required to determine whether raloxifene will improve implant fixation.

Measurement of mechanical and fatigue properties using unified, simple-geometry specimens: Cold spray additively manufactured pure metals

A methodology that allows joint determination of fundamental engineering properties of materials/components vital to their efficient design and a safe service lifetime operation is presented. Using a combination of recently developed techniques, a simultaneous assessment of mechanical properties , fatigue crack growth rates, as well as fracture toughness is described. All these are performed using unified-geometry samples that are simple and easy to produce. The mechanical properties are measured in tensile and compressive modes, while the combination of developed bending test methods (quasi-static four-point bending and fatigue bending) enables to cover the fatigue loading from very low loads corresponding to crack propagation threshold values up to the high loads corresponding to a static fracture of the fracture toughness test. To validate and complement the bending data, additional resonant ultrasonic measurements of the corresponding properties are carried out. The methodology is partially suitable for testing of cold sprayed deposits. Therefore, Al, Cu, Ni and Ti deposits are tested and compared to cold-rolled sheet reference samples. The results are quantified in the form of NASGRO equation, widely used in software for prediction of fatigue lives . Together, the obtained set of data may be readily used for modeling of the performance of cold sprayed parts. Finally, fractographic analysis of the failed specimens is presented to describe the mechanisms leading to failure. At low loads, the reference sheets and the cold sprayed deposits exhibit similar behavior, where the cracks grow in a trans-crystalline mode without any significant interaction with deposit particle boundaries. Contrary to this, the behavior changes at higher loads: the particle interfaces in the cold sprayed deposits become the weak point and the cracks grow at high rates by inter-particle decohesion, while the sheet materials generally fail by striation mechanism at much lower rates. • A methodology for simultaneous determination of stress-strain, fatigue crack growth rate and fracture toughness is presented. • Samples of unified, easy-to-manufacture geometry are used for all tests. • Crack growth can be predicted at different stress intensity levels using NASGRO model fitted to the crack growth rate data. • Engineering characterization of stress-strain behavior and NASGRO model provide ready-to-use inputs for numerical modeling. • CS deposits behave similarly to reference sheets in low loads range. At higher loads, inter-particle interfaces decrease their performance.

Stiffness of a type II external skeletal fixator and locking compression plate in a fracture gap model.

To compare the stiffness of constructs fixed with a type II external skeletal fixator (ESF) or a 3.5-mm locking compression plate (LCP) in axial compression and bending with a fracture gap model. Quasi-static four-point bending and axial compression tests. Ten LCP and 10 ESF immobilizing epoxy cylinders with a 40-mm fracture gap. Five constructs of each type were tested in nondestructive mediolateral (ML) four-point bending and then rotated and tested in nondestructive craniocaudal (CC) four-point bending. Five additional constructs of each type were tested in nondestructive axial compression. Stiffness was compared between loading modes by construct type and between construct types by loading mode. Type II ESF were stiffer than LCP in ML bending (difference, 1474 N/mm, P < .0001) and in axial compression (difference, 458 N/mm, P = .008) but not in CC bending (P = .1673). Type II ESF were stiffer in ML bending than in CC bending (difference, 999 N/m, P < .0001), while LCP were stiffer in CC bending than in ML bending (difference, 634 N/mm, P < .0001). Type II ESF generated stiffer constructs compared with LCP in ML bending and in axial compression without a difference in CC bending. External skeletal fixator and LCP bending stiffness varied by loading direction. A type II ESF should be considered in a comminuted fracture requiring increased stability in ML and axial directions.

Mechanical characterization of lightweight foam-based sandwich panels

Foam-based composite structures are widely used in the field of construction market for roofing and closing walls. This paper presents a mechanical characterization of a lightweight sandwich panels with foam core. The faces of the panels are made of thin steel sheets, and for the core, closed-cell polyurethane foam with a density of 40 kg/m3 was used. Mechanical testing consists of quasi-static four-point bending, transversal tensile and compression tests. All experimental tests were conducted at room temperature in accordance to EN 14509:2013 Standard. With the data obtained from experimental tests, load–displacement curves and mechanical properties are presented. Following the experimental tests, the elastic characteristics (shear modulus, tensile E-modulus, compression modulus), strength properties (ultimate shear strength, transverse tensile strength, compression strength) and energy absorption performances were determined.

Cure monitoring and structural health monitoring of composites using micro-braided distributed optical fibre

In this paper, cure monitoring of a composite laminate is conducted, followed by subsequent structural health monitoring (SHM). A distributed optical fibre (DOF) sensor was embedded between glass fibre fabric plies during manufacture; part of the DOF length was micro-braided using glass fibres, while the remaining length was left 'bare' (as-received condition).In situand real-time strain measurement during the infusion and curing processes of the laminate was completed. Cure monitoring of composite materials using different fibre orientations, sensor locations, raw materials, and manufacturing methods has been widely studied. However, no consensus was reached due to differences in raw materials, temperature profile, manufacturing method, fibre orientation, and sensor location. The manufactured composite plate was then subjected to repeated loading during a quasi-static four-point bending test, and the strain development along the length of the DOF was recorded. Comparable results were obtained from the micro-braided and bare sections of the DOF, showing the suitability of micro-braided optical fibres for real-time strain monitoring in composite structures. The micro-braiding DOF facilitates handling for automated manufacturing methods and can be used to follow the full life cycle of a composite from fabrication till end-of-life.

Effects of detailing on the blast and post-blast resilience of high-strength steel reinforced concrete (HSS-RC) beams

This paper examines the influence of reinforcement detailing and fibers on the static and blast performance of beams built with high-strength concrete (HSC) and high-strength (HS) steel reinforcement. The beams in this study had dimensions of 125 mm × 250 mm × 2440 mm (b × d × L), and were built with HSC and Grade 690 MPa ASTM A1035 reinforcement. Longitudinal reinforcement in tension consisted of either 2-No.4 or 2-No.5 high-strength bars (ρ = 1% or 1.5%), while transverse reinforcement consisted of closed ties or open-stirrups made from 6 mm wire arranged at various spacing (s). Group A beams (6 specimens) were designed according to modern blast standards, with top continuity bars and closely spaced ties at s = 50 mm (d/4) throughout the beam span, while Group B beams (2 specimens) were designed with high-strength fiber-reinforced concrete (HSFRC) and a larger tie spacing of s = 100 mm (d/2). The performance of the beams is compared to that of a control set of singly-reinforced beams with “nominal detailing” consisting of open-stirrups spaced at s = 100 mm (d/2) in the shear spans only - Group C. Blast tests were conducted using a shock-tube with companion beams tested under quasi-static four-point bending. The use of blast detailing in Group A is found to significantly enhance the ductility of the high-strength steel reinforced concrete beams under static loading, allowing for full utilization of the high-strength bars in tension. Improved detailing also leads to important enhancements in blast behavior, including better control of displacements, increased blast capacity and high damage tolerance when compared to the Group C control specimens. Moreover, the results from Group B demonstrate that fibers can be used to relax transverse steel detailing without compromising ductility or performance under both static and blasts loads. The ability of high-strength steel to reduce steel requirements is also demonstrated. Moreover, the post-blast performance of the beams is assessed through residual static testing of the blast-damaged beams. The results show that blast detailing and fibers allow for significant residual post-blast resistance and energy-absorption capacity. As part of the analytical study the blast response of the test beams is predicted using 2D finite element (FE) modelling. The results show that the FE procedure which employed the Disturbed Stress Field Model was able to accurately capture the peak load and failure mode of the beams under static conditions. Under blast loading, the model also captured the displacement response of the beams up to first peak, however the accuracy reduced at subsequent cycles, with the results found to be sensitive to the choice of damping coefficients.

Contactless optical measurement methods for glass beams and composite timber-glass I-beams

The main purpose of this paper is to briefly present the concept of timber-glass I-beams and the accuracy of optical measurement methods for structures made from glass. The concept of timber-glass I-beams combines the best features of both materials and maximises of their safety. Previous investigations of glass beams and composite timber-glass beams and optical measuring methods are briefly discussed at the beginning of this paper. The investigation of simply supported glass beams using quasi-static four-point bending tests was the next stage of the examination to compare contact and contactless measurement methods. Composite timber-glass I-beams were then investigated in the same manner as the glass beams. The composite timber-glass I-beams were constructed from fir, laminated float glass and polyurethane adhesive – offering the best performance when used with both timber and glass.

Flexural behavior of composite sandwich panel of aluminum foam and epoxy resin

The mechanical properties in bending tests of an integrated composite sandwich panel of aluminum foam and epoxy resin were studied through quasi-static four-point bending tests. The failure modes and typical force–cross-head curves were obtained. The bending rigidity, energy absorption capacity and flexural bearing capacity of the panel were analyzed compared to those of the traditional sandwich panel. The test results indicate that this kind of composite sandwich panel has good integrality and stability. The typical force–cross-head displacement curves present three phases: elastic phase, strengthening phase and destruction phase. The flexural rigidity, energy absorption capacity and flexural bearing capacity are affected by composite layer thickness and specimen thickness, and the specimen with a composite layer of 2·5 mm has the optimal behavior. The mechanical properties of the integrated composite sandwich panel have been highly improved compared with those of the traditional sandwich panel. The specimens maintain good stability under bending, and no peeling-off or cracking appears between the composite layer and core.

A Proximally-Adjustable Variable Length Intramedullary Nail: Ex Vivo Quasi-Static and Cyclic Loading Evaluation

An adjustable-length intramedullary (IM) nail may reduce both complications secondary to fracture fixation and manufacturing costs. We hypothesized that our novel nail would have suitable mechanical performance. To test this hypothesis, we manufactured three prototypes and evaluated them in quasi-static axial compression and torsion and quasi-static four-point bending. Prototypes were dynamically evaluated in both cyclic axial loading and four-point bending and torsion-to-failure. The prototypes exceeded expectations; they were comparable in both quasi-static axial stiffness (1.41 ± 0.37 N/m in cervine tibiae and 2.30 ± 0.63 in cadaver tibiae) and torsional stiffness (1.05 ± 0.26 N·m/deg in cervine tibiae) to currently used nails. The quasi-static four-point bending stiffness was 80.11 ± 09.360, greater than reported for currently used nails. A length-variance analysis indicates that moderate changes in length do not unacceptably alter bone-implant axial stiffness. After 103,000 cycles of axial loading, the prototype failed at the locking screws, comparable to locking screw failures seen clinically. The prototypes survived 1,000,000 cycles of four-point bend cyclic loading, as indicated by a consistent phase angle throughout cyclic loading. The torsion-to-failure test suggests that the prototype has adequate resistance to applied torques that might occur during the healing process. Together, these results suggest that our novel IM nail performs sufficiently well to merit further development. If brought to market, this adjustable-length IM nail could reduce both patient complications and healthcare costs.