Notch Location Research Articles

Effect of the notch location on the Charpy-V toughness results for robotic flux-cored arc welded multipass joints

Abstract In this study, the effect of the notch locations on the Charpy-V toughness values of the all-welded joint obtained using robotic flux-cored arc welding was investigated with respect to microstructures at the notch locations. Charpy impact tests were performed through the thickness with notch location at the centerline as well as off-set regions of the weld metal in addition to the microhardness measurements conducted. The detailed weld metal characterization was conducted using a stereo microscope, optical microscope, and scanning electron microscope at the same location where the Charpy tests and microhardness tests were performed. The sub-zero impact toughness test results indicated that the columnar weld metal regions exhibited low toughness values while the centerline microstructure consisting of mainly reheated regions displayed much higher toughness values even at the test temperature of −60 °C, satisfying the toughness requirement of the requested 47 J value. It is concluded that a small variation of the through-thickness notch position may result in different toughness values for the same weld metal. On this basis, the notching procedure of the Charpy-V samples for the multi-pass weld metal should be conducted with care and obtained results should be explained with respective notch position and microstructure.

Finite element analysis of fracture behavior in ceramics: Competition between artificial notch and internal defects under three-point bending

Evaluation of the nonlinear relationship between the surface defect size and fracture strength of ceramics is important for engineering applications. In this study, we aim to predict the apparent nonlinear relationship between the defect size and fracture strength of single-edge notched beams (SENBs) using the finite element method. Specifically, we applied the methodology for predicting fracture strength from microstructure distribution data (relative density, pore size, aspect ratio, and grain size) to a finite element analysis (FEA) model in which the shape and size of the initial defects are defined at notch locations. By reproducing the apparent nonlinearity caused by the competition between the surface and internal defects within the framework of linear elastic fracture mechanics, the effectiveness of the FEA methodology for the evaluation of strength scatter and allowable crack size in ceramics was demonstrated.

Experimental study on fatigue crack propagation in balcony opening corners of a cruise ship

The balcony opening corner in a cruise ship is subjected to highly stress concentration and alternating loading during operation, which is prone to cause fatigue crack initiation and further crack propagation. These initiated cracks are difficult to find in time due to these opening corners being hidden in the decoration materials. It is necessary to assess the residual fatigue lives accurately and provide reasonable repairing plans for these cracked opening corners to ensure safety of the cruise. In this paper, in order to study the fatigue crack propagation (FCP) law of the balcony opening corner, make up the lack of the FCP experiment of the balcony opening corners, correlate the FCP behavior of the full scale model with the reduced scale model, and provide an accurate FCP live prediction method for balcony opening corners, reduced scale models based on the similarity theory and the corresponding fixtures are designed. FCP tests of these reduced scale models with small initial cracks are carried out. a-N curves of the cracks at different notch locations in balcony opening corners under different stress ratios are obtained. Formulas of stress intensity factors (SIFs) of cracks at the midpoint of the three types of corners are given by fitting the data obtained by a serial of FE analysis of the cracked corners. Further, the fatigue lives of the tested specimens are calculated and compared with the test data. It is shown that the prediction results fit well with the model test results. The procedure of model test and experimental data can provide a reference for detailed design and precise residual FCP life assessment of opening corners in ship hulls.

The parietal notch (Brammer's pointer): Accuracy of a surface landmark for temporal bone surgery.

HypothesisThe parietal notch is a reliable surface landmark of the sigmoid sinus at the sinodural angle.BackgroundCurrently no surface landmark approximates the anterior border of the sigmoid sinus. Additionally, the temporal line may not accurately identify the tegmen near the sinodural angle. This study examines the reliability of the parietal notch as a surface landmark of the sigmoid sinus at the sinodural angle.MethodsForty‐seven cadaveric temporal bones were used to identify the parietal notch by two observers. The parietal notch and sinodural angle were labeled with radiopaque markers, mounted on foam, and CT imaged in the axial plane. The horizontal and vertical distances between the labeled landmarks were measured using PACS software.ResultsThe parietal notch location was identified in 43/47 specimens. The notch was posterior to the sinodural angle in 90.6% and superior in 65% of the specimens. The average horizontal and vertical distance between the two landmarks was 6.1 mm (SD = 5.4) and 0.8 mm (SD = 8.7), respectively. In 60% of the specimens the parietal notch was within 6 mm of the sinodural angle in the horizontal dimension.ConclusionsThe parietal notch is identified in most temporal bones. It also approximates the anterior boarder of the sigmoid sinus and level of the tegmen due to its proximity to the sinodural angle. The parietal notch helps to define the posterosuperior margins of a mastoid dissection and may assist surgeons during mastoid surgery.

Bending stiffness prediction to mass timber panel-concrete composite floors with notched connections

Mass timber panel-concrete composite floors consist of bottom timber panels, a top concrete layer, and a connection system in between. Notched connections made by filling concrete into the grooves cut on timber are one of the most structurally effective and cost-saving solutions to connect concrete topping to mass timber panels. However, the notched connections are not standardized due to various shapes of grooves and reinforcing techniques, and design guidelines are inadequate in terms of effective measures to achieve high composite efficiencies in notch-connected composite floors. This study developed an empirical formula to determine the shear stiffness of notched connections based on numerical modeling. The proposed formula was verified by comparing the predicted floor bending stiffness using the discrete bond composite beam model with the test results. A parametric study was then carried out to study the effects of geometry factors, including notch depth, timber shear length, number of notches, and thickness of concrete, on the overall bending stiffness of the composite floor. It has been found that the maximum composite efficiency in a mass timber panel-concrete composite floor can be achieved through optimizing the number, size, and locations of notches. The analytical and numerical investigations on the composite floors also demonstrate that in a certain range the thickness ratio between concrete and timber has little impact on the composite floor bending stiffness.

An anatomical study for the location of suprascapular and spinoglenoid notches using three-dimensional computed tomography images of scapula.

BackgroundThe optimal position for creating portals for arthroscopic suprascapular nerve decompression has not been sufficiently verified. Therefore, this study aimed to investigate the anatomical characteristics of the scapula for optimal portal creation using 3-dimensional computed tomography images. The posterolateral corner of the acromion was designated as the starting point for measurements because there is no secondary ossification center present.MethodsThis study included 223 patients (females, 129; males, 94) who underwent computed tomography of the shoulder joint. Three-dimensional images of the scapula were created, and the distance from the posterolateral corner of the acromion to the suprascapular and spinoglenoid notches was measured. Additionally, the correlation coefficient with height and the differences between the female and male groups were investigated.ResultsThe distances from the posterolateral corner of the acromion to the suprascapular and spinoglenoid notches were 42.9 ± 4.6 and 31.5 ± 3.6 mm, respectively, and their correlation coefficients with height were 0.12 and 0.067, respectively. There was no significant difference in the distance from the posterolateral corner of the acromion to the suprascapular (42.5 ± 4.1 vs. 43.9 ± 5.1 mm, P = .098) and to the spinoglenoid (31.4 ± 3.3 mm vs. 32.0 ± 3.9 mm, P = .12) notches between the female and male groups.ConclusionRegardless of height and sex, the distances from the posterolateral corner of the acromion to the suprascapular and spinoglenoid notches were approximately 43 and 32 mm, respectively. Therefore, creating portals at these locations may be effective for arthroscopic suprascapular nerve decompression.

Tentorial Notch Meningiomas: Innovative Preoperative Management and Literature Review.

BackgroundTentorial meningiomas account for only 3–6% of all intracranial meningiomas. Among them, tentorial incisura (notch) location must be considered as a subgroup with specific surgical anatomy and indications, morbidity, and mortality. In this study, we propose an update on preoperative management in order to reduce postoperative deficits.MethodsWe retrospectively collected adult patients treated for incisural meningioma between January 1992 and December 2016 in two different neurosurgical departments. Demographic, clinical, and neuroradiological preoperative and postoperative data were analyzed. In the most recent subgroup of tumors, a preoperative digital simulation was performed to define a volumetric digital quantification of the tumor resection. A review of the pertinent literature has been also done.ResultsWe included 26 patients. The median age was 58.4 years. Onset neurological signs were cranial nerve deficit in 9 patients, hemiparesis in 7, gait disturbance in 3, and intracranial hypertension in 3 patients. Simpson grade I removal was achieved in 12 patients, II in 10, III in 3, and IV in 1 patient. An overall rate of 23% postoperative complications was observed. The average follow-up duration was 68.5 months. Residual tumor was reported in 8 patients. Five patients underwent gamma knife radiosurgery. In 34.6% of patients, the surgical approach was chosen with preoperative digital planning estimating the potential volume of postoperative residual tumor, the target for radiosurgical treatment.ConclusionsA multidisciplinary approach to plan incisural meningiomas management is important. To lower postoperative morbidity and mortality, a careful preoperative case analysis is useful. A planned residual tumor, supported by preoperative simulation imaging, could be safely treated with radiosurgery.

Fatigue behavior of notched steel beams strengthened by a prestressed CFRP plate subjected to wetting/drying cycles

Prestressed carbon fiber reinforced polymer (CFRP) strengthening is effective in suppressing crack propagation of steel beams. However, the fatigue behavior of notched steel beams with prestressed CFRP under a hygrothermal environment is not fully understood. Generally, notch machining on the steel beam is an ordinary method to simulate a fatigue defect for laboratory tests. In this study, the interfacial energy release rate at the notch location was first derived for strengthened steel beams. The theoretical results show that the interfacial energy release rate can be significantly reduced by prestressed CFRP strengthening, contributing to improving the interfacial fatigue performance. In addition, notched steel beams strengthened by prestressed CFRP (with a prestress level of 25% of tensile strength of CFRP plate) were exposed to wetting/drying cycles (WDCs) and then tested under fatigue loading. The experimental results show that prestressed CFRP strengthening increases the fatigue resistance of interfacial debonding initiation and failure 3.47 times and 7.83 times, respectively, which agrees with the tendency revealed by the theoretical results. In contrast, WDC exposure reduced the fatigue lives of interfacial debonding initiation and failure by 34.6% and 27.2%, respectively. An S – N curve based on the maximum principal interfacial stress at the notch location was proposed to predict the tendency of fatigue life of debonding initiation for strengthened steel beams. Moreover, the tendency prediction for fatigue life of interfacial debonding development for the strengthened steel beams with/without WDC exposure was developed based on Paris’ law. • Theoretically reveals that the prestressed CFRP reduces the interfacial energy release rate. • Prestressed CFRP strengthening significantly improves interfacial fatigue life. • Hygrothermal exposure leads to a significant reduction of interfacial fatigue life.

Notch-type damage influence on the frequency of the principal mode of the composite cantilever beam flexural vibrations

The results of calculation investigations aimed at the determination of the influence mechanisms of the surface damage in the form of a rectangular notch and fibers’ orientation on the frequency of the principal mode of the composite cantilever beam flexural vibrations are presented. The three-dimensional finite element model of the beam made of the unidirectional carbon-fiber-reinforced plastic with the local surface rectangular notch-type damage has been developed using the effective modulus concept to determine the composite material elastic properties. Its adequacy is corroborated via the comparison of the determination results of the principal frequency of flexural vibrations of the intact beam as a function of the degree of anisotropy in composite material with the known experimental data. In this paper has been found the mechanisms of influence of the damage parameters (notch depth and its location along the beam length) and the degree of anisotropy of the elastic properties in composite material, which is defined by the angle of the fibers, on the variation of the frequency of the principal mode of flexural vibrations. It is established that there is such a notch location along the beam length for its specified depth and width, the so-called transition point, where the natural frequency of vibrations of the damaged and intact beams are equal independent of the angle of the fibers. This fact indicates that there is a simultaneous damage effect on both the variation of flexural stiffness of the beam and its inertia properties. The location of the transition point depends on the notch depth and fibers’ orientation. With the larger distance of the notch from the transition point to the free end, the principal frequency of vibrations of the damaged beam becomes larger as compared with that one for the intact beam.

Morphometric Study of Cadaveric Spleen in Vidarbha Region

Background: Spleen is one of the largest lymphoid organs that are involved in haemopoitic function also during fetal life. Its anatomy is useful not only for Anatomist but also for Surgeons, Radiologists and Physicians. A lot of variations are observed in the spleen from its shape to size which is important to diagnose or treat the number of diseases.
 Methodology: This study was carried out on 60 spleens in the dissection hall of our medical college which were removed during routine undergraduate dissection. The parameters studies were shape of the spleen, number of notches (single or multiple), location of notches (Superior or inferior border), weight, breadth, width or length.
 Results: The 90% spleens has single notch. The weight of the spleens ranges from 89 gm to 220 gm with an average 142.6 gm. Range of breadth observed 3.5cm to7.4cm with an average 5.8cm, Range of width observed 2.8cm to 5.7cm with an average 4.1cm. Range of length observed 8.1cm to13.2cm with an average 11.7cm.
 Conclusion: Morphological variation is very common in spleen and varies according to the genetic, geographic, nutrition and work habits of individual and varies regions to regions of India. Morphological analysis is under reported and need to be carry out at different regions and places for obtaining more accurate data.

Flexural behaviour of notched steel beams strengthened with a prestressed CFRP plate subjected to fatigue damage and wetting/drying cycles

Applying a prestressed Carbon Fibre Reinforced Polymer (CFRP) to strengthen deficient steel structures is a favourable approach. However, fatigue loading and hygrothermal exposure can weaken adhesive bonding. A theoretical analysis of the interfacial stress distribution at the notch location was first carried out to explain the mechanism of delay of the interfacial debonding of notched steel beams after prestressed CFRP strengthening. Then, the prestress loss and flexural behaviour of specimens (with a prestress level of 25%) subjected to fatigue damage (FD) and/or wetting/drying cycles (WDCs) with 3.5 wt% NaCl solution were further experimentally investigated. Theoretical results showed that prestressed CFRP strengthening can significantly reduce the interfacial stress at the notch site and delay interfacial debonding. The CFRP prestress loss mainly occurs in the hardening stage of the adhesive layer, and the total prestress loss is less than 2.7% for specimens subjected to WDC exposure, indicating the effectiveness of the end anchorage system. The adhesive microcracks at the notch induced by FD and adhesive bonding degradation caused by WDCs significantly affect the interfacial debonding. In addition, NaCl solution penetration accelerated by microcracks causes further degradation of interfacial bonding. Nevertheless, the end anchorage system showed promising stiffness and load-carrying capacity behaviour for the specimens subjected to FD, WDCs, and the combined effects. The mixed failure mode of CFRP fracture and CFRP extraction from the end anchorage demonstrates that the strength of the CFRP plate was thoroughly utilized for the specimens with prestressed CFRP.

A directional continuous wavelet transform of mode shape for line-type damage detection in plate-type structures

Line-type damage is abundant in engineering structures that have been in service for a long time. Vibration-based nondestructive testing as a global method has been extensively used in structural damage identification. In this study, a two-dimensional directional continuous wavelet transform (2D-DCWT)-based damage identification algorithm using “Morlet2d” wavelet for line-type damage detection in plate structures is presented. An analytical long narrow notch-type damage model of simply-supported plates is proposed to evaluate line-type damage effect on plate vibration performance. Based on the proposed model, the biggest challenge in parameter selection of wavelet analysis is solved. The fundamental aspects of 2D-DCWT algorithm in term of notch location and orientation are assessed. A multi-mode shape fusion approach is presented to make the 2D-DCWT algorithm apply to the high-order mode shapes. A comparative study with isotropic “Mexcan-hat2d” wavelet-based damage identification is performed, and it demonstrates that the proposed 2D-DCWT algorithm is superior in noise immunity. The efficiency and practicability of the 2D-DCWT algorithm are certified by an experimental modal test on damage detection of an artificially-induced notched aluminum alloy clamped plate using excitation-response system of the Piezoelectric Leadzirconate-Titanate (PZT) and Scanning laser Doppler Vibrometers (SLDV). As demonstrated in both the analytical and experimental investigation, the suggested approach may successfully identify line-type damage in plate-type structures.

When is tinkering with safety net programs harmful to beneficiaries?

AbstractInteractions between redistributive policies can confront low‐income households with complicated choices. We study one such interaction, namely the relationship between Medicaid eligibility thresholds and the minimum wage. A minimum wage increase reduces the number of hours a low‐skilled individual can work while retaining Medicaid eligibility. We show that the empirical and welfare implications of this interaction can depend crucially on the relevance of labor market frictions. Absent frictions, affected workers may maintain Medicaid eligibility through small reductions in hours of work. With frictions, affected workers may lose Medicaid eligibility unless they leave their initial job. Empirically, we find that workers facing this scenario became less likely to participate in Medicaid, less likely to work, and more likely to spend time looking for new jobs, including search while employed. The observed outcomes suggest that low‐skilled workers face substantial labor market frictions. Because adjustment is costly, tinkering with safety net program parameters that determine the location of program eligibility notches can be harmful to beneficiaries.

Novel Si/SiGe fin on insulator fabrication on bulk-Si substrate

In this paper, novel Si/SiGe fin on insulator (FOI) structure fabrication on bulk-Si substrate is systematically explored. A notched Si/SiGe fin etching is first achieved by using a novel three-step etching after a high-quality of SiGe layer epitaxially grown is realized on a Si substrate by optimizing the epitaxial process. To fabricate the Si/SiGe FOI structure, isolation of upper Si/SiGe fin above the notch is investigated by a direct rapid thermal anneal (RTA) oxidation scheme, spike anneal post SiGe fin reveal scheme, and SiN spacer protection scheme. It is found that all these three schemes can achieve the upper Si/SiGe isolation at the notch location, but the direct RTA oxidation scheme suffers the issue of serious oxidation of SiGe fin because SiGe is more easily oxidized than Si in O2 ambient. Furthermore, compared with the direct oxidation scheme, the spike anneal post SiGe fin reveal scheme can attain an obvious better SiGe fin profile. However, there is still a minor lateral loss of SiGe fin caused by the oxidation of SiGe fin due to the residual O2 in N2 ambient. The SiN film covering the revealed SiGe fin before spike anneal treatment may be an effective solution to avoid the oxidation of SiGe fin. Meanwhile, SiN spacer protection scheme by employing a SiN spacer post the step-I etching of the three-step etching can realize the Si/SiGe FOI structure and protect the upper SiGe fin from oxidation during the low-temperature RTA oxidation process. Therefore, using the SiN film or spacer to protect SiGe from oxidation is a necessary way to fabricate the Si/SiGe FOI structure. Meanwhile, the SiN spacer protection scheme with a relative low temperature RTA isolation oxidation is a prefer choice compared with the spike anneal post SiGe fin reveal scheme.

Autonomous Lidar-Based Monitoring of Coastal Lagoon Entrances

Intermittently closed and open lakes or Lagoons (ICOLLs) are characterised by entrance barriers that form or break down due to the action of wind, waves and currents until the ocean-lagoon exchange becomes discontinuous. Entrance closure raises a variety of management issues that are regulated by monitoring. In this paper, those issues are investigated, and an automated sensor solution is proposed. Based upon a static Lidar paired with an edge computing device. This solar-powered remote sensing device provides an efficient way to automatically survey the lagoon entrance and estimate the berm profile. Additionally, it estimates the dry notch location and its height, critical factors in the management of the lagoon entrances. Generated data provide valuable insights into landscape evolution and berm behaviour during natural and mechanical breach events.

Femoral Neck Notching in Dual Mobility Implants: Is This a Reason for Concern?

BackgroundDual mobility (DM) total hip arthroplasty (THA) implants have been advocated for patients at risk for impingement due to abnormal spinopelvic mobility. Impingement against cobalt-chromium acetabular bearings, however, can result in notching of titanium femoral stems. This study investigated the incidence of femoral stem notching associated with DM implants and sought to identify risk factors. MethodsA multicenter retrospective study reviewed 256 modular and 32 monoblock DM components with minimum 1-year clinical and radiographic follow-up, including 112 revisions, 4 conversion THAs, and 172 primary THAs. Radiographs were inspected for evidence of femoral notching and to calculate acetabular inclination and anteversion. Revisions and dislocations were recorded. ResultsTen cases of femoral notching were discovered (3.5%), all associated with modular cylindrospheric cobalt-chromium DM implants (P = .049). Notches were first observed radiographically at mean 1.3 years after surgery (range 0.5-2.7 years). Notch location was anterior (20%), superior (60%), or posterior (20%) on the prosthetic femoral neck. Notch depth ranged from 1.7% to 20% of the prosthetic neck diameter. Eight cases with notching had lumbar pathology that can affect spinopelvic mobility. None of these notches resulted in stem fracture, at mean 2.7-year follow-up (range 1-7.6 years). There were no dislocations or revisions in patients with notching. ConclusionFemoral notching was identified in 3.5% of DM cases, slightly surpassing the dislocation rate in a cohort selected for risk of impingement and instability. Although these cases of notching have not resulted in catastrophic failures thus far, further study of clinical sequelae is warranted. Component position, spinopelvic mobility, and implant design may influence risk.

Pulmonary Doppler Notch Pattern in Relation with Pulmonary Vascular Resistance Index in Patients with Atrial Septal Defect

Background: Atrial septal defect (ASD) potentially causes pulmonary hypertension (PH) and increased pulmonary vascular resistance (PVR). In previous studies, pulmonary Doppler notch was evident in patients with high PVR. There was a distinct notch pattern in different types of PH. This study aims to examine whether echocardiographic notch pattern could estimate PVR in secundum ASD patients.
 Methods: Cross sectional study was conducted in secundum ASD patients ≥18 years old who underwent clinically indicated right heart catheterization. Association of notch presence and PVR index (PVRi) and correlation of notch ratio (NR), a parameter of notch location, and PVRi were analyzed. The best cut off of NR value was obtained using the receiver operating characteristics curve.
 Results: Among 60 patients, the notch was present in 50 patients (83%) and significantly associated with PVRi ≥6 WU.m2 (p<0.0001). Notch ratio and PVRi had a moderate negative correlation (r=-0.410, p=0.003). Receiver operating characteristics curve with area under curve 0.709 showed that cutoff NR value of 1.635 was a good discriminator for PVRi ≥6 WU.m2, with 70% sensitivity, 70% specificity, 56.8% positive predictive value, and 14.9% negative predictive value. Patients were then classified into three groups of notch pattern based on its presence and location, which was significantly associated with PVRi (p<0.0001).
 Conclusions: Pulmonary Doppler notch pattern is associated with PVRi in secundum ASD patients. This may be used clinically to estimate PVR to aid patient selection for further invasive investigation.
 
 Keywords: atrial septal defect, Doppler echocardiography, notch, notch ratio, pulmonary vascular resistance

Crack growth analysis and remaining life prediction of dissimilar metal pipe weld joint with circumferential crack under cyclic loading

Fatigue crack growth model has been developed for dissimilar metal weld joints of a piping component under cyclic loading, where in the crack is located at the center of the weld in the circumferential direction. The fracture parameter, Stress Intensity Factor (SIF) has been computed by using principle of superposition as KH + KM. KH is evaluated by assuming that, the complete specimen is made of the material containing the notch location. In second stage, the stress field ahead of the crack tip, accounting for the strength mismatch, the applied load and geometry has been characterized to evaluate SIF (KM). For each incremental crack depth, stress field ahead of the crack tip has been quantified by using J-integral (elastic), mismatch ratio, plastic interaction factor and stress parallel to the crack surface. The associated constants for evaluation of KM have been computed by using the quantified stress field with respect to the distance from the crack tip. Net SIF (KH + KM) computed, has been used for the crack growth analysis and remaining life prediction by Paris crack growth model. To validate the model, SIF and remaining life has been predicted for a pipe made up of (i) SA312 Type 304LN austenitic stainless steel and SA508 Gr. 3 Cl. 1. Low alloy carbon steel (ii) welded SA312 Type 304LN austenitic stainless-steel pipe. From the studies, it is observed that the model could predict the remaining life of DMWJ piping components with a maximum difference of 15% compared to experimental observations.

Investigations on the fracture behavior of Inconel 718 superalloys obtained from cast and additive manufacturing processes

This paper examines the effects of manufacturing processes on the fracture behavior of Inconel 718 alloy at room temperature. This comparative study was conducted on specimens obtained from cast and PBF (Power Bed Fusion) additive manufacturing. Mechanical testing was conducted on single edge notch specimens in bending. In order to quantify the influence of the manufacturing process on the fracture behavior, the J-R curves were obtained from the energy per unit of fracture surface area needed to drive crack growth in agreement with the ASTM standard E1820-01. Depending on the specimen type and the location of the initial notch with respect to the lasing planes, crack initiation significantly differs resulting from specific microstructures. These differences may explain why AM specimens have much higher fracture toughness at initiation (about 70–100%) and subsequent crack propagation. The in situ crack propagation was studied via the observations of the crack path along with the mechanical loading. An original picture analysis was developed to monitor the crack growth based on the location of the crack tip at specimen surface.

Surface Defects Sensitivity during the Unfolding of Corrugated Struts Made by Powder‐Bed Additive Manufacturing

Corrugated struts as part of lattice structures can lead to novel mechanical behavior by a combination of material and geometrical hardening. The unfolding behavior of such struts offers a potential of large macroscopic straining. However, their ability to be unfolded is impacted by the surface characteristics inherited from the additive manufacturing process. Herein, the unfolding sensitivity to these surface characteristics is evaluated. Corrugated struts with varying surface roughness are produced using a combination of electron beam powder‐bed fusion to produce corrugated samples with different nominal diameters and chemical etching assisted by micro‐computed tomography (CT) to achieve a given final diameter. In situ micro‐CT tensile tests are conducted to track the evolution of the struts morphology under loading. Surface defects play a significant role in the unfolding ability of such struts. They are characterized either by a global roughness or by a local notch depth. A quite broad unfolding dispersion remains for samples with the same level of roughness. A finer description of notch depth and location within the gauge length allows a more accurate prediction of the unfolding ability. A model for predicting the probability of failure during unfolding is presented.