Stability of an Aircraft Structure in a Strength Test Frame

1947 ◽  
Vol 51 (440) ◽  
pp. 704-714 ◽  
Author(s):  
P. B. Walker
Keyword(s):  
Structural Strength ◽  
General Rule ◽  
Strength Test ◽  
Strength Testing ◽  
Structural Failure ◽  
Considerable Time ◽  
Aircraft Structure ◽  
Strength Tests ◽  
Test Frame ◽  
Actual Test

The part played by major structural strength tests in aeroplane design is well known. Without such tests the standard of safety for aircraft would soon decline and excess weight, as an insurance against structural failure, would become a general rule. Considerable time and effort are expended therefore in the early stages of each new design of aeroplane to check by actual test whether its strength meets requirements. It is clearly reasonable to devote some little further time and effort to the study of methods and technique for strength testing in general.

scholarly journals EARLY STRENGTH TESTING AFTER ACL RECONSTRUCTION IMPACTS ISOKINETIC STRENGTH PERFORMANCE AT TIME OF RETURN TO SPORT

2021 ◽  
Vol 9 (7_suppl3) ◽  
pp. 2325967121S0011
Author(s):  
Adam Weaver ◽  
Dylan Roman ◽  
Maua Mosha ◽  
Nicholas Giampetruzzi
Keyword(s):  
Test Performance ◽  
Knee Extension ◽  
Strength Test ◽  
Strength Testing ◽  
Isokinetic Strength ◽  
Rehabilitation Process ◽  
Strength Performance ◽  
Knee Extension Strength ◽  
Isometric Knee Extension ◽  
Strength Tests

Background: The standard of care in ACL reconstruction (ACLR) typically involves standardized strength testing at 6 months or later to assess a patient’s readiness to return to play (RTP) using isokinetic and isometric testing, and functional strength testing. Recent literature suggests that isokinetic knee extension strength should demonstrate 89% limb symmetry index (LSI) or greater prior to returning to sport. However, there is little known on the effects of strength testing early in the rehabilitation process and the relationship to strength test performance at time of RTP. Purpose: The purpose of this study was to examine how early post-operative strength test performance impacts isokinetic strength outcomes at RTP testing in adolescents. Methods: The retrospective cohort study included patients undergoing primary ACLR between 12 and 18 years of age, early post-operative strength measures, and isokinetic dynamometer strength at RTP from July 2017 and April 2019. Data was dichotomized into desired outcomes at 3 months: >70% isometric knee extension LSI, > 20 repetitions on anterior stepdown test (AST), > 90% LSI Y Balance. At RTP testing, isokinetic knee extension strength data was categorized into >89% LSI at 3 speeds (300, 180, 60°/sec). Chi square testing and odds ratio statistics were used to examine association and its magnitude. Results: 63 patients met inclusion criteria (38 females; 15.37±1.66 years old). >70% LSI isometric knee extension strength at 3 months showed a significant association (Table 2) and demonstrated the strongest odds of having >89% LSI on isokinetic strength tests at all 3 speeds at RTP with 180°/sec being the highest (OR=14.5; 95% CI=4.25,49.43; p= <0.001). Performance on AST showed a significant association (χ2 (1, n=63) = 17.00, p <0.001), and highest odds at 180°/sec (OR=4.61; 95% CI = 1.59, 13.39, p=<0.001) and 60°/sec (OR= 3.07; 95% CI = 1.10, 8.63, p= 0.04). Combination of performance on isometric strength tests and AST showed a significant association to isokinetic strength at all three speeds, but less predictive then isometrics in isolation. (Table 2). There was no significant relationship between YBR LSI at 3 months and isokinetic strength at 6 months. Conclusion: Standardized strength testing early in rehabilitation can help identify patients that will successfully complete RTP testing. Our results suggest that isometric knee extension strength and timed anterior stepdown test provide meaningful clinical information early in the rehabilitation process. This data also suggests that the use of YBAL for predicting isokinetic strength performance is limited. [Table: see text][Table: see text]

Destructive Energy in Aircraft Pressure Cabins

1950 ◽  
Vol 54 (472) ◽  
pp. 235-241 ◽  
Author(s):  
P. B. Walker
Keyword(s):  
Strain Energy ◽  
General Rule ◽  
Strength Testing ◽  
Testing Technique ◽  
Noticeable Effect ◽  
Noise And Vibration ◽  
Aircraft Structures ◽  
Strength Tests

The energy that is suddenly released when a structure fails under load usually presents one of the minor problems in strength testing technique. Care has to be taken to ensure that the strain energy in the structure does not do further damage after primary failure and so obscure the location of the original weakness; and the possibility of risks to personnel must not be overlooked. As a general rule, however, aircraft structures fail in strength tests without untoward effects. Most of the strain energy within the structure is absorbed internally or dissipated in loading gear and anchorages, and the most noticeable effect is the noise and vibration which is produced.

scholarly journals AN INVESTIGATION OF THE STRUCTURAL STRENGTH OF TRANSTIBIAL SOCKETS FABRICATED USING CONVENTIONAL METHODS AND RAPID PROTOTYPING TECHNIQUES

2019 ◽  
Author(s):  
Brittany Pousett ◽  
Aimee Lizcano ◽  
Silvia Ursula Raschke
Keyword(s):  
3D Printing ◽  
Rapid Prototyping ◽  
Ultimate Strength ◽  
Stance Phase ◽  
Structural Strength ◽  
Static Strength ◽  
Strength Test ◽  
Manufacturing Method ◽  
Strength Tests ◽  
3D Printed

BACKGROUND: Rapid Prototyping is becoming an accessible manufacturing method but before clinical adoption can occur, the safety of treatments needs to be established. Previous studies have evaluated the static strength of traditional sockets using ultimate strength testing protocols outlined by the International Organization for Standardization (ISO). OBJECTIVE: To carry out a pilot test in which 3D printed sockets will be compared to traditionally fabricated sockets, by applying a static ultimate strength test. METHODOLOGY: 36 sockets were made from a mold of a transtibial socket shape,18 for cushion liners with a distal socket attachment block and 18 for locking liners with a distal 4-hole pattern. Of the 18 sockets, 6 were thermoplastic, 6 laminated composites & 6 3D printed Polylactic Acid. Sockets were aligned in standard bench alignment and placed in a testing jig that applied forces simulating individuals of different weight putting force through the socket both early and late in the stance phase. Ultimate strength tests were conducted in these conditions. If a setup passed the ultimate strength test, load was applied until failure. FINDINGS: All sockets made for cushion liners passed the strength tests, however failure levels and methods varied. For early stance, thermoplastic sockets yielded, laminated sockets cracked posteriorly, and 3D printed socket broke circumferen-tially. For late stance, 2/3 of the sockets failed at the pylon. Sockets made for locking liners passed the ultimate strength tests early in stance phase, however, none of the sockets passed for forces late in stance phase, all broke around the lock mechanism.  CONCLUSION: Thermoplastic, laminated and 3D printed sockets made for cushion liners passed the ultimate strength test protocol outlined by the ISO for forces applied statically in gait. This provides initial evidence that 3D printed sockets are statically safe to use on patients and quantifies the static strength of laminated and thermoplastic sockets. However, all set-ups of sockets made for locking liners failed at terminal stance. While further work is needed, this suggests that the distal reinforcement for thermoplastic, laminated and 3D printed sockets with distal cylindrical locks may need to be reconsidered. LAYMAN’S ABSTRACT 3D printing is a new manufacturing method that could be used to make prosthetic sockets (the part of the prosthesis connected to the individual). However, very little is known about the strength of 3D printed sockets and if they are safe to use. As Prosthetists are responsible for providing patients with safe treatments, the strength of 3D printed sockets needs to be established before they can be used in clinical practice. The strength of sockets made using current manufacturing methods was compared to those made using 3D printing. Strength was tested using the static portion of the ISO standard most applicable for this situation which outlines the forces a socket must take at 2 points in walking–when the foot is placed on the ground (early stance) and when the foot pushed off the ground (late stance). Sockets made for two prosthetic designs (cushion and locking) were tested to determine if one is safer than the other. All sockets made for cushion liners passed the standard for forces applied statically. However, different materials failed in different ways. At early stance, thermoplastic sockets yielded, laminated composite sockets cracked and 3D printed sockets broke circumferentially. At late stance other components failed 2/3 of the time before the sockets were affected. This provides initial evidence that sockets made for cushion liners are statically safe to use on patients. Sockets made for locking liners failed around the end, showing that 3D printing should not be used to create sockets with the design tested in this study. Article PDF Link: https://jps.library.utoronto.ca/index.php/cpoj/article/view/31008/24937 How to Cite: Pousett B, Lizcano A, Raschke S.U. An investigation of the structural strength of transtibial sockets fabricated using conventional methods and rapid prototyping techniques. Canadian Prosthetics & Orthotics Journal. 2019; Volume2, Issue1, No.2. DOI: https://doi.org/10.33137/cpoj.v2i1.31008 CORRESPONDING AUTHORBrittany Pousett, BSc, MSc, Certified Prosthetist,Head of Research at Barber Prosthetics Clinic,540 SE Marine Dr, Vancouver, British Colombia V5X 2T4, Canada.Email: [email protected]

Isometric Strength Test Consistency over Time

1983 ◽  
Vol 27 (9) ◽  
pp. 790-793
Author(s):  
Terrence J. Stobbe ◽  
Ralph W. Plummer ◽  
Donald P. Shreves
Keyword(s):  
Financial Burden ◽  
Strength Test ◽  
Isometric Strength ◽  
Strength Testing ◽  
Test Results ◽  
Testing Protocol ◽  
Strength Tests ◽  
Test Population ◽  
Student Volunteer ◽  
Over Time

Workmen's Compensation costs have become a major financial burden on industry. A significant part of these costs are the result of musculoskeletal injuries. One method of controlling these injuries is matching employees to jobs based on strength. Isometric strength testing has been shown to be an effective method of matching employee strength capability to job strength requirements. The use of screening test raises the question of test-retest consistency. This study was designed to determine the consistency of isometric strength test results over time. Thirteen student volunteer subjects (10m, 3F) participated in a testing protocol consisting of five strength tests performed a minimum of two times each at two week intervals. Four test sessions were held. An analysis of variance was used to identify week to week strength differences in the test population. Each of the five tests was analyzed separately and no significant week to week strength differences were found. This result further supports the validity of using isometric strength testing as a selection tool.

scholarly journals Handgrip strength and muscle fatigue among footwear industry workers

2016 ◽  
Vol 29 (2) ◽  
pp. 317-324 ◽  
Author(s):  
Lidiane Angélica Cotelez ◽  
Maysa Venturoso Gongora Buckeridge Serra ◽  
Eliane Ramos ◽  
José Eduardo Zaia ◽  
Flávia Oliveira Toledo ◽  
...  
Keyword(s):  
Muscle Strength ◽  
Muscle Fatigue ◽  
Handgrip Strength ◽  
Strength Test ◽  
Strength Testing ◽  
Test Results ◽  
Irreversible Damage ◽  
Low Correlation ◽  
Footwear Industry ◽  
The Mean

Abstract Introduction: Muscle fatigue can be defined as a decrease in the performance of the neuromuscular system in generating force. This situation is considered a complex physiological process involving various body systems, in order to avoid irreversible damage or even cell death. Objective: The aim of this study was to measure muscle strength in order to assess the level of fatigue among footwear industry workers, and to determine a possible correlation between muscle strength and the perception of reported fatigue. Materials and Methods: The study included 32 male workers from the footwear industry with a mean age of 34.63 ± 11.98 years. The workers performed the handgrip strength test using a handheld dynamometer, and completed the Bipolar Fatigue Questionnaire. Results: The mean result of strength testing was 23.1 ± 8.3 kgf, and the mean score of the fatigue questionnaire was 2.28 ± 0.93 points. However, a low correlation was observed between the results of the fatigue questionnaire and the strength test results. Conclusion: The grip strength results of the footwear workers were below the values for the general Brazilian population, a fact that may indicate potential muscle fatigue. However, a low correlation with the perception of fatigue was indicated by the questionnaire.

scholarly journals PENGARUH PENGGUNAAN LIMBAH PLASTIK POLYPROPYLENE (PP) SEBAGAI CAMPURAN AGREGAT KASAR TERHADAP KUAT TEKAN DAN TARIK PADA BETON FC’ 25 MPA

2019 ◽  
Vol 3 (2) ◽  
pp. 81-89
Author(s):  
Angga Pirman Firdaus ◽  
Jonbi
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Strength Test ◽  
Plastic Waste ◽  
Concrete Mixture ◽  
Strength Testing ◽  
Concrete Compressive Strength ◽  
Tensile Strength Test ◽  
Compressive Strength Test ◽  
Waste Mixture

Indonesia ranks second in the world's largest plastic waste producer after China. Each year, Indonesia can contributeup to 187.2 million tons of plastic waste, while China reaches 262.9 million tons of plastic waste. Based on the data, one way to utilize plastic waste by using plastic waste as a mixture of concrete, where the plastic used is polypropylene (PP) plastic with different percentage of concrete mixture, the test includes compressive strength test and tensile concrete. The results of concrete compressive strength testing with polypropylene (PP) plastic waste mixture of 5%, 10% and 15% at age 28 in aggregate aggregate mixture decreased by 5.15%, 6.89% and 13.53%. As for the result of concrete tensile strength test with polypropylene (PP) plastic waste mixture of 5%, 10% and 15% at age 28 in crude aggregate mixture decreased 17,61%, 24,13% dan 23,24%.

scholarly journals Strength Tests and Numerical Simulations of Loess Modified by Desulfurization Ash and Fly Ash

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 512
Author(s):  
Zhi Cheng ◽  
Xinrong Cheng ◽  
Yuchao Xie ◽  
Zhe Ma ◽  
Yuhao Liu
Keyword(s):  
Shear Strength ◽  
Fly Ash ◽  
Power Plants ◽  
Utilization Rate ◽  
Direct Shear ◽  
Test Results ◽  
Mass Ratio ◽  
Direct Shear Tests ◽  
Strength Tests ◽  
Actual Test

Desulfurization ash and fly ash are solid wastes discharged from boilers of power plants. Their utilization rate is low, especially desulfurization ash, most of which is stored. In order to realize their resource utilization, they are used to modify loess in this paper. Nine group compaction tests and 32 group direct shear tests are done in order to explore the influence law of desulfurization ash and fly ash on the strength of the loess. Meanwhile, FLAC3D software is used to numerically simulate the direct shear test, and the simulation results and the test results are compared and analyzed. The results show that, with the increase of desulfurization ash’s amount, the shear strength of the modified loess increases first and then decreases. The loess modified by the fly ash has the same law with that of the desulfurization ash. The best mass ratio of modified loess is 80:20. When the mass ratio is 80:20, the shear strength of loess modified by the desulfurization ash is 12.74% higher than that of the pure loess on average and the shear strength of loess modified by fly ash is 3.59% higher than that of the pure loess on average. The effect of the desulfurization ash on modifying the loess is better than that of the fly ash. When the mass ratio is 80:20, the shear strength of loess modified by the desulfurization ash is 9.15% higher than that of the fly ash on average. Comparing the results of the simulation calculation with the actual test results, the increase rate of the shear stress of the FLAC3D simulation is larger than that of the actual test, and the simulated shear strength is about 8.21% higher than the test shear strength.

A Structural Test Frame with Automatic Loading

1949 ◽  
Vol 53 (466) ◽  
pp. 997-1008
Author(s):  
F. W. Page ◽  
J. C. King
Keyword(s):  
Large Scale ◽  
Material Testing ◽  
Test Equipment ◽  
Structural Components ◽  
Standard Material ◽  
Structural Test ◽  
Strength Tests ◽  
Test Frame ◽  
Automatic Loading

The Design of test frames of all types owes a great deal to the pioneer work of the Structures Department, Royal Aircraft Establishment. This particular frame contains some novel features and has been subjected to some unusual overall calibration tests, particularly in relation to the entirely automatic and centralised control gear.The choice of apparatus for testing large scale structural components may be influenced by many factors. In the present case, the choice of a test frame rather than other types of equipment was governed by the following considerations.In an industrial establishment it is essential that test equipment should be put to maximum use. Unlike a central testing establishment such as the R.A.E., major strength tests are relatively infrequent and therefore the equipment should also be suitable for as much as possible of the development and research testing which cannot be undertaken on standard material testing machines.

Assessment of post-heat behavior of cement mortar incorporating silica fume and granulated blast-furnace slag

2020 ◽  
Vol 11 (2) ◽  
pp. 221-246
Author(s):  
Ghasem Pachideh ◽  
Majid Gholhaki
Keyword(s):  
Tensile Strength ◽  
Flexural Strength ◽  
Blast Furnace Slag ◽  
Strength Test ◽  
Content Type ◽  
Granulated Blast Furnace Slag ◽  
Cement Mortars ◽  
Strength Tests ◽  
Pozzolanic Materials ◽  
Furnace Slag

Purpose With respect to the studies conducted so far and lack of researches on the post-heat behavior of cement mortars containing pozzolanic materials, the purpose of this paper is to investigate the post-heat mechanical characteristics (i.e. compressive, tensile and flexural strength) of cement mortars containing granulated blast-furnace slag (GBFS) and silica fume (SF). In doing so, selected temperatures include 25, 100, 250, 500, 700 and 9000c. Last, the X-ray diffraction test was conducted to study the microstructure of mixtures and subsequently, the results were presented as power-one mathematical relations. Design/methodology/approach Totally, 378 specimens were built to conduct flexural, compressive and tensile strength tests. Accordingly, these specimens include cubic and prismatic specimens with dimensions of 5 × 5 × 5 cm and 16 × 4 × 4 cm, respectively, to conduct compressive and flexural strength tests together with briquette specimen used for tensile strength test in which cement was replaced by 7, 14 and 21 per cent of SF and GBFS. To study the effect of temperature, the specimens were heated. In this respect, they were heated with a rate of 5°C/min and exposed to temperatures of 25 (ordinary temperature), 100, 250, 500, 700 and 900°C. Findings On the basis of the results, the most profound effect of using GBFS and SF, respectively, takes place in low (up to 250°C) and high (500°C and greater degrees) temperatures. Quantitatively, the compressive, tensile and flexural strengths were enhanced by 73 and 180 per cent, 45 and 100 per cent, 106 and 112 per cent, respectively, in low and high temperatures. In addition, as the temperature elevates, the particles of specimens containing SF and GBFS shrink less in size compared to the reference specimen. Originality/value The specimens were cured according to ASTMC192 after 28 days placement in the water basin. First, in compliance with what has been specified by the mix design, the mortar, including pozzolanic materials and superplasticizer, was prepared and then, the sampling procedure was conducted on cubic specimens with dimension of 5 × 5 × 5 mm for compressive strength test, prismatic specimens with dimensions of 16 × 4 × 4 mm for flexural strength test and last, briquette specimens were provided to conduct tensile strength tests (for each temperature and every test, three specimens were built).

scholarly journals Bonding of plywood 

2016 ◽  
Vol 62 (No. 4) ◽  
pp. 198-204
Author(s):  
M. Brožek
Keyword(s):  
Tensile Strength ◽  
Testing Machine ◽  
Strength Testing ◽  
Bonded Joints ◽  
Rupture Force ◽  
Oblique Direction ◽  
Direction Angle ◽  
Economical Evaluation ◽  
Wood Bonding ◽  
Strength Tests

The contribution contains results of bonded joints strength tests. The tests were carried out according to the modified standard ČSN EN 1465 (66 8510):2009. The spruce three-ply wood of 4 mm thickness was used for bonding according to ČSN EN 636 (49 2419):2013. The test samples of 100 × 25 mm size were cut out from a semi-product of 2,440 × 1,220 mm size in the direction of its longer side (angle 0°), in the oblique direction (angle 45°) and in the direction of its shorter side (crosswise – angle 90°). The bonding was carried out using eight different domestic as well as foreign adhesives according to the technology prescribed by the producer. All used adhesives were designated for wood bonding. At the bonding the consumption of the adhesive was determined. After curing, the bonded assemblies were loaded using a universal tensile-strength testing machine up to the rupture. The rupture force and the rupture type were registered. Finally, the technical-economical evaluation of the experiments was carried out. 

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