Strength Members Research Articles

DOMEX 700W

Abstract Domex 700W is an extra high strength member of the Domex family of cold-forming steels, which are thermomechanically rolled and where all the processing is carefully controlled. The Domex alloys are advanced high-strength steels that reduce the weight of heavy vehicles, trailers, cranes, and containers. The "W" signifies a weather-resistant steel. This datasheet provides information on composition, physical properties, tensile properties, and bend strength as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, and joining. Filing Code: SA-705. Producer or source: SSAB Swedish Steel Inc..

Longitudinal Vibration Response of a Vibration Isolation Module with Kevlar-29 Fabric Strength Member

The longitudinal vibration response of a simplified model of a vibration isolation module used in an underwater towed acoustic sensor array is estimated by finite element method and validated by impact resonance tests using a lumped mass system. The viscoelastic properties of the Kevlar-29 fabric strength member of the vibration isolation module are determined from transient tensile tests at different preloads and strain rates based on a five-parameter discrete viscoelastic model. Close agreement between finite element estimates and experimental results are obtained when strain rates of the strength member during viscoelastic parameter estimation tests and impact tests are matched.

The Numerical Investigation of Cracking Areas under Nonuniform Settlements of the Construction

We investigate the tensely-strained state of three-dimensional construction at the measured settlements of the foundation. The numerical model of the construction is developed within the limits of the theory of the plates bending and rectilinear rods, it allows to reveal dangerous places in the strength members particularly in the interfloor plate. The three-dimensional model of the dangerous area is developed, which allows to define the level of damaging the plates material. Settlements levels leading to first cracks and full destruction of the investigated area of the construction are defined.

DOMEX 550W

Abstract Domex 550W is an extra high strength member of the Domex family of cold-forming steels, which are thermomechanically rolled and where all the processing is carefully controlled. The alloy is used in cold formed and welded products. The Domex alloys are advanced high-strength steels that reduce the weight of heavy vehicles, trailers, cranes, and containers. The "W" signifies a weather resistant steel. This datasheet provides information on composition, physical properties, tensile properties, and bend strength as well as fracture toughness. It also includes information on forming, heat treating, and joining. Filing Code: SA-688. Producer or source: SSAB Swedish Steel Inc..

Вычисление некоторых показателей качества и надежности для системы с параллельно нагруженными элементами

Вычисление некоторых показателей качества и надежности для системы с параллельно нагруженными элементами

Experimental - theoretical study of axially compressed cold formed steel profiles

Analysis of axially compressed steel members made of cold formed profiles presented in this paper was conducted through both experimental and numerical methods. Numerical analysis was conducted by means of "PAK" finite element software designed for nonlinear static and dynamic analysis of structures. Results of numerical analysis included ultimate bearing capacity with corresponding middle section force-deflection graphs and buckling curves. Extensive experimental investigation were also concentrated on determination of bearing capacity and buckling curves. Experiments were conducted on five series with six specimens each for slenderness values of 50, 70, 90, 110 and 120. Compressed simply supported members were analyzed on Amsler Spherical pin support with unique electronical equipment and software. Besides determination of forcedeflection curves, strains were measured in 18 or 12 cross sections along the height of the members. Analysis included comparisons with results obtained by different authors in this field recently published in international journals. Special attention was dedicated to experiments conducted on high strength and stainless steel members.

Crack Growth Analysis of the Landing Gear Pull Rod of the Fighter Jet Aircraft

Crack Growth Analysis of the Landing Gear Pull Rod of the Fighter Jet AircraftThis paper describes the problem of searching for the causes of damage in the form of rupture of a strength member of the main landing gear. There have been two incidents noted which both occurred during hangar storage. It should be pointed out that the two occurrences mentioned concern a particular aircraft currently in operation, and that these incidents occurred a few days after the last flight.This article presents part of the investigation process needed to determine the causes of cracks in the test item. The crack growth analysis of the pull rod was performed using the NASGRO software. In order to perform the calculations, the information was gathered during previously conducted material studies and flight tests.

Component Seismic Damage Model for SRHSHPC Joints

The deficiency of present damage model is generalized by studying existing references. The mechanical properties of steel reinforced high strength and high performance concrete (SRHSHPC) members under monotonic loading, including the capacity of ultimate deformation, strength, stiffness, etc. are analyzed after the different number of cycles. The reduction factor is introduced, the dynamic variation relationship of ultimate deformation with the number of cycles is obtained, and the merits of existing damage model are utilized, finally the seismic damage model, which is suitable for SRHSHPC beam-column joints, is established. In order to verify the rationality of damage model, Opensees as a nonlinear analysis program is adopted to simulate SRHSHPC joints, the comparison of the numerical analysis results with experimental results shows that the proposed damage model can capture the behaviors of joints very well. The model can, therefore, be used to carry out seismic damage analysis of other SRHSHPC members.

Viscoelastic properties of Kevlar-29 fabric tape strength member

Kevlar ®-29 strength members find wide application in tow lines, mooring lines, oil rig pendants and underwater sensor systems. In this paper, the dynamic mechanical properties of Kevlar-29 fabric tape strength member are characterized by semi-empirical means. A series of transient and harmonic tests were conducted for a typical configuration taking into account of time scales and operating conditions of practical interest. Constitutive relations based on three-parameter and five-parameter spring-dashpot discrete models were used for extracting the properties from transient tests. The parameter values obtained through transient tests were transformed to complex modulus in the frequency domain. Comparison in the frequency domain was made between the results obtained through transient tests and harmonic tests. Effects of preload and stress rates were studied. It is observed that storage modulus increases and loss factor decreases with increase in preload. At very low frequencies, analysis of the transient tests using discrete models shows lower storage modulus values compared to harmonic tests and hence does not provide reliable estimation. At higher frequencies, i.e., above 8 Hz, five-parameter discrete model based on transient tests can adequately estimate both the storage modulus and loss modulus. The transient tests indicate a rise in the loss factor at mid frequencies whereas the harmonic tests give almost flat response. Also the modulus of Kevlar fabric tape increases with increase in stress rate. Nonlinear behaviour is noticed throughout the tensile deformation response.

Progressive collapse analysis of thin-walled box columns

Box columns are often used as main strength members of various types of thin-walled structures such as ships, ship-shaped offshore structures, and aerospace structures. Until and after the ultimate limit state is reached, box columns exhibit highly nonlinear structural behavior in terms of geometrical and material aspects. In particular, the effects of local buckling, global buckling, and their interaction play a significant role in the resulting consequences of box columns under extreme actions. In order to calculate the maximum load-carrying capacity of box columns, it is thus highly required to perform the progressive collapse analysis to take into account progressive failures of individual components and their interacting effects. The aim of the present study is to demonstrate a method that is useful for the progressive collapse analysis of thin-walled box columns in terms of computational efficiency and accuracy. Theoretical outline of the method is addressed. Short, medium and long box columns in length are studied in terms of interacting effects between local component failure modes and global system failure modes. The effect of unloaded edge conditions of individual plate elements is also studied. A comparison of the method with more refined nonlinear finite element method computations is made.

1212 コンパティビリティを考慮した自動車設計の評価指標の検討

A new concept called Compatibility appeared in the field of automobile designs. Compatibility designs require to protect not only the safety of the own driver and passengers but also that of driver and passengers in another car at collision. There are not so many researches on compatibility design of cars and the performance indices to evaluate the compatibility have not been fully studied among them. In this study structural interaction problem between front strength members of mutual cars are of interest as one of significant problems. Five performance indices are shown and discussed through crash numerical simulations making use of detail FEM models. Then crash numerical simulations are carried out using two models and virtual barrier to measure the crash load distribution in stead of loadcells.

Axial Compression and Bending Characteristics of CFRP Hat Shaped Member According to Orientation Angle

The strength members, such as front-end side members, are subjected to axial compressive and bending load during collision. Therefore, it is important to consider energy absorption by the axial compression and the bending for design of effective strength members. And at the same time, it also should consider reducing weight of the members. In this study, CFRP (Carbon Fiber Reinforced Plastics) side members with single-hat-section shape were manufactured. The axial compression and the bending tests were performed for the members using universal testing machine, and the axial compression and the bending characteristics were analyzed. Stacking condition related to the energy absorption of composite materials is being considered as an issue for the structural efficiency. So the energy absorption of the member under the axial compressive load and the bending load were experimentally investigated.

A new 122 mm electromechanical drill for deep ice-sheet coring (DISC): 4. Drill cable

AbstractThe deep ice-sheet coring (DISC) drill developed by Ice Coring and Drilling Services (ICDS) under contract with the US National Science Foundation requires a drill cable capable of transmitting high amounts of electrical power as well as high rates of data. The DISC cable was designed and manufactured by the Rochester Corporation to core ice to depths of 4000 m. In addition to the steel strength members to support the drill, the cable has copper wires for conducting electrical power for the drill sonde cutter, pump motors and the sonde electronics and an optical fiber core for data transmission. The outer steel layers are filled with a special compound to minimize fluid penetration of the cable.

Development of Synthetic Fiber-Reinforced Electro-Optical-Mechanical Cables for Use With Moored Buoy Observatories

We consider an alternative to traditional high-modulus synthetic electro-optical-mechanical (EOM) mooring cables that are being used in single-point moorings for deep-ocean observatories. The alternative cable design is based on using low-modulus nylon or polyester fibers as the strength member. High-modulus EOM cables such as those that use Vectran fibers as the strength member are usually constructed with the conductors and optical fibers in the core and the strength member on the outside. The key aspect of the new design is that the strength member is placed in the center of the cable and the conductors and fibers are wrapped around the outside at a high helix angle to accommodate stretching of the center-strength-member. A comparison of the static and dynamic responses of moorings constructed with nylon, polyester, and Vectran EOM cables (for mooring scopes of 1.1 and 1.2 and deployment depths of 1800, 3000, and 5000 m) shows that the maximum total tensions of moorings made with nylon EOM cables are lowest under all conditions. Differences between the nylon and the Vectran EOM cable moorings are due principally to the differences in the dynamic tensions. Differences between the nylon and the polyester EOM cable moorings are due mainly to differences in static tensions caused by the higher specific gravity of polyester fibers. Reduction in the scope of all the moorings from 1.2 to 1.1 resulted in significantly higher tensions for the polyester and Vectran EOM cable moorings but only slightly higher tensions for the nylon EOM cable moorings

Development of a triaxial pressure-velocity probe for deep submergence applications

A triaxial pressure-velocity probe has been developed for the purpose of measuring the ambient acoustic noise field in the ocean at frequencies below 500 Hz. The probe consists of an omnidirectional hydrophone, a compliantly suspended sphere containing a triaxial geophone, and an electronics housing that contains a four-channel preamplifier and a digital compass. All of these components are packaged in a frame which in turn is attached to a deployment cable (i.e., a strength member) and submerged to a prescribed depth. The performance specifications for the transducers include a submergence depth rating of 6 km and a noise floor of 40 dB re: 1 mPa2 per hertz. These two parameters essentially drive the design of the probe and the paper will address these topics from the standpoint of the design evolution that took place in order to meet the specifications. Other aspects of the probe’s development include efforts to mitigate flow-induced noise and shielding the compass from the magnetic field emitted by the geophones. Test data obtained on a prototype unit will be presented. [Work supported by C. M. Traweek at the Office of Naval Research Code 321MS.]

Effect of Thermal Barrier Coating Layer on HIP Treated IN738LC Fatigue Characteristic

The fatigue characteristic of thermal barrier-coated Ni-base superalloy IN738LC at room temperature was studied by fatigue test using SEM-servo testing machine. In order to eliminate the influence of micro-shrinkage in IN738LC and purely investigate the effect of TBC on fatigue characteristic, HIP treated IN738LC was used in comparison with NON-HIP treated one. The results indicate that HIP treatment is effective to remove micro-shrinkage and fatigue life is greatly improved. The TBC coating layer is a strength member in the small test specimen at room temperature, and TBC coated material showed lower fatigue life rather than IN738LC without TBC.

알루미늄 샌드위치 패널의 구조적 형상 및 진동 특성에 관한 연구

Aluminum honeycomb sandwich panel (AHSP) not only have high flexural rigidity and strength per density but also excellence in anti-vibration and anti-noise properties. Their properties are very useful for build airplane and high speed crafts, which need lighter-weighted and more strengthed element. Recently, the AHSP is regarded as a promising strength member of light structures like the hull of high speed crafts. Generally, the core shape of aluminum sandwich panel (ASP) is the hexagonal shape of honeycomb. But, in this paper, authors proposed the ASP with pyramid core, as the ASP model of new type, and analysed the structural and vibrational characteristics for aluminum pyramid sandwich panel (APSP) as this new ASP type, according to the thickness variation of core and face, the height variation of core. The applied sandwich models have isotropic and symmetrical aluminum faces and pyramid cores. And, the applied boundary conditions are simple, fixed and free support.

Monitoring of Mechanical Behaviours of Composite Shear Fastener Joint (1st Report, Basic Principle of Measurement)

The composite materials have been expanding their application field in aircraft industries taking the advantage of their excellent mechanical properties such as high specific stiffness and strength. At present, the composite materials are come to use not only as thin plate shells but also as thicker strength members. But the failure and fracture process and property of the composites are complicated comparing with usual metallic materials. This paper presents a method to monitor some mechanical behaviors and conditions at composite joint portions using a strain sensor embedded into fastener bolt. This method enables us to grasp the information related to the structural integrity at joint portions online. In this report, the basic principles of the measurement system are shown by numerical calculations for elementary models.

Statistical properties of the maximum elastoplastic story drift of steel frames subjected to earthquake load

The concept of performance based seismic design has been gradually accepted by the earthquake engineering profession recently, in which the cost-effectiveness criterion is one of the most important principles and more attention is paid to the structural performance at the inelastic stage. Since there are many uncertainties in seismic design, reliability analysis is a major task in performance based seismic design. However, structural reliability analysis may be very costly and time consuming because the limit state function is usually a highly nonlinear implicit function with respect to the basic design variables, especially for the complex large-scale structures for dynamic and nonlinear analysis. Understanding statistical properties of the structural inelastic deformation, which is the aim of the present paper, is helpful to develop an efficient approximate approach of reliability analysis. The present paper studies the statistical properties of the maximum elastoplastic story drift of steel frames subjected to earthquake load. The randomness of earthquake load, dead load, live load, steel elastic modulus, yield strength and structural member dimensions are considered. Possible probability distributions for the maximum story are evaluated using K-S test. The results show that the choice of the probability distribution for the maximum elastoplastic story drift of steel frames is related to the mean value of the maximum elastoplastic story drift. When the mean drift is small (less than 0.3%), an extreme value type I distribution is the best choice. However, for large drifts (more than 0.35%), an extreme value type II distribution is best.

Development of Energy-Absorbing Composite Utility Pole

The serious hazard presented by unforgiving timber utility poles installed along the nation’s roadways has long been recognized by the roadside safety community. However, relatively little attention has been devoted to the development of safer utility poles beyond breakaway timber pole designs. A new generation of utility pole designs that use energy-absorbing composite materials offers a solution to the development and implementation of safer utility poles that have a cost advantage over breakaway timber poles and can be tailored to achieve the desired functional performance and energy absorption characteristics inherently without the need for additional strength members or add-on energy absorption devices. This research has resulted in the development of an energy-absorbing fiberglass-reinforced composite (FRC) utility pole design that meets structural performance requirements for environmental loading in accordance with the National Electrical Safety Code for Class 4 poles and safety performance criteria in compliance with NCHRP Report 350 Test Level 2 conditions for utility poles. Developmental testing and analyses were performed to support the development of a prototype design for demonstration testing. Full-scale crash testing has demonstrated the ability of the composite pole to absorb the vehicle’s impact energy by progressive crushing and fracture propagation as the vehicle is brought to a controlled stop. In addition to offering improved safety performance, the energy-absorbing FRC pole provides significant functional advantages, such as reduced weight, an improved strength-to-weight ratio, increased longevity, ease of installation, low maintenance, and resistance to environmental degradation.