Estimation of Failure Parameters for Finite Element Simulations Based on a Single State of Stress and Arbitrary Stress-Strain Relation

2014 ◽  
Author(s):  
Lars O. Voormeeren ◽  
Carey L. Walters ◽  
Lisa Tang ◽  
Alex W. Vredeveldt
Keyword(s):  
Yield Condition ◽  
Failure Criteria ◽  
The State ◽  
Small Scale ◽  
Storage Tanks ◽  
Hardening Law ◽  
State Of Stress ◽  
Offshore Industry ◽  
Lng Fuel ◽  
Von Mises

Crash analysis in the maritime and offshore industry typically relies on failure criteria that are based only on uniaxial states of stress. However, it is well known that the failure strain depends on the state of stress, and the state of stress in ship collisions is not necessarily uniaxial. Although more detailed failure models are routine in other industries, the cost of finding the parameters for these models remains a barrier within the maritime and offshore industry. This paper explores an approach of applying the Modified Mohr-Coulomb (MMC) failure criterion based on a single tension test. This is based on the observation that there is only a single independent calibration parameters when a von Mises yield locus and plane stress are assumed. The MMC yield condition is also generalized by applying it to an arbitrary stress versus strain relationship, which does not follow the power hardening law. Results of impact tests on small-scale cryogenic storage tanks filled with water and air are presented and are used to validate the adjustments made above. This validation test also shows how the above findings can be applied to storage tanks for LNG fuel on inland waterway ships.

scholarly journals Experimental analysis of the state of stress in a steel – titanium perforated plate loaded with concentrated force

2020 ◽  
Vol 15 (55) ◽  
pp. 277-288
Author(s):  
Mateusz Konieczny ◽  
Grzegorz Gasiak ◽  
Henryk Achtelik
Keyword(s):  
Experimental Analysis ◽  
Maximum Stress ◽  
Ammonia Synthesis ◽  
Perforated Plate ◽  
The State ◽  
Von Mises Stress ◽  
Concentrated Force ◽  
State Of Stress ◽  
Plate Perforation ◽  
Von Mises

The paper presents an experimental analysis of the state of stress, free supported on the edge of a steel – titanium circular perforated plate loaded with a centrally concentrated force, created in the technological process of explosion welding. For this purpose, a special test stand was designed and a methodology for testing the perforated plate was developed. Resistance strain gauges were used to measure the state of strain. The load was applied in the center of the plate to a pressure stamp. As a result of the research, the values of radial, circumferential and equivalent von Mises stress were obtained as a function of the radius of the plate perforation circle and its load. The stress distribution topography revealed the zones of maximum stress of the steel – titanium perforated plate. The proposed method of experimental research can be used by engineers to verify the state of stress, e.g. in the designed tube sheet walls of reactors for ammonia synthesis.

scholarly journals Influence of the applied layer on the state of stress in a bimetallic perforated plate under two load variants

2021 ◽  
Vol 15 (56) ◽  
pp. 137-150
Author(s):  
Mateusz Konieczny ◽  
Grzegorz Gasiak ◽  
Henryk Achtelik
Keyword(s):  
Perforated Plate ◽  
Single Layer ◽  
External Pressure ◽  
The State ◽  
Von Mises Stress ◽  
Stress Tests ◽  
Concentrated Force ◽  
State Of Stress ◽  
Base Steel ◽  
Von Mises

The paper presents the results of the analysis of the influence of the applied plate layer on the state of stress in the bimetallic perforated plate. The finite element method ANSYS program was used for numerical calculations. The paper presents the results of stress tests for a single-layer clad plate made of S355J2 steel and a bimetallic perforated plate consisting of layers made of S355J2 steel and titanium. In addition, the study presents the results of the research on the influence of the method of loading, i.e. the concentrated force P in the geometric center of the plate and the external pressure q on the entire surface of the plate, and the method of support, i.e. free support and fixed, on the location of stress concentration zones in the bimetallic circular perforated plate. It has been shown that the presence of a perforated layer in the plate reduces the value of the equivalent von Mises stress by a minimum of approximately 30% in the base (steel) layer.

Effect of Loading Conditions on Deformation and Failure of Composite Sandwich Structures

2001 ◽  
Author(s):  
Isaac M. Daniel ◽  
Emmanuel E. Gdoutos ◽  
Jandro L. Abot ◽  
Kuang-An Wang
Keyword(s):  
Failure Modes ◽  
Axial Loading ◽  
Bending Moment ◽  
Adhesive Bond ◽  
Failure Criteria ◽  
The State ◽  
Deformation And Failure ◽  
Composite Sandwich ◽  
State Of Stress ◽  
Aluminum Honeycomb

Abstract An investigation was conducted of failure modes and criteria for their occurrence in composite sandwich columns and beams. The initiation of the various failure modes depends on the material properties of the constituents (facings and core), geometric dimensions and type of loading. The loading type or condition determines the state of stress throughout the sandwich structure, which controls the location and mode of failure. The appropriate failure criteria at any point of the structure account for the biaxiality or triaxiality of the state of stress. The specimens were made of unidirectional carbon/epoxy facings and aluminum honeycomb and PVC closed-cell foam cores. The constituent materials were fully characterized and, in the case of the foam core, failure envelopes were developed for general two-dimensional states of stress. Sandwich specimens were loaded under bending moment, shear and axial loading and failure modes were observed and compared with analytical predictions. The failure modes investigated are face sheet compressive failure, adhesive bond failure, indentation failure, core failure and facing wrinkling. The transition from one failure mode to another for varying loading or state of stress was discussed. Experimental results were compared with analytical predictions.

scholarly journals Half-plane contacts subject to remote tension

2021 ◽  
pp. 030932472098844
Author(s):  
Nils Cwiekala ◽  
David A Hills
Keyword(s):  
Contact Problem ◽  
Half Plane ◽  
Asymptotic Form ◽  
Fretting Fatigue ◽  
The State ◽  
Partial Slip ◽  
Practical Relevance ◽  
Plane Contact ◽  
State Of Stress ◽  
Plane Contact Problem

The state of stress present in an elastic half-plane contact problem, where one or both bodies is subject to remote tension has been investigated, both for conditions of full stick and partial slip. The state of stress present near the contact edges is studied for different loading scenarios in an asymptotic form. This is of practical relevance to the study of contacts experiencing fretting fatigue, and enables the environment in which cracks nucleate to be specified.

scholarly journals Effect of the Rock Stress on the Water Jet Cutting Performance

2021 ◽  
Author(s):  
Battista Grosso ◽  
Valentina Dentoni ◽  
Augusto Bortolussi
Keyword(s):  
Numerical Models ◽  
Step Function ◽  
Water Jet ◽  
The State ◽  
Cutting Performance ◽  
Lagrangian Analysis ◽  
State Of Stress ◽  
Water Jet Cutting ◽  
Cutting Rate ◽  
Available Technology

AbstractUnderground quarrying is rarely adopted for granite extraction due to the difficulties in the implementation of traditional technologies (drilling and explosive). As alternative to drilling and explosive, the combination of diamond wire and water jet seems to be the most promising available technology. The cutting performance achievable with the water jet technology depends on the operative parameters, the material characteristics and the state of stress within the rock massif. To assess the effect of the state of stress on the cutting rate, laboratory tests have been performed with an oscillating water jet machine on granite samples subjected to a static load. The stress distribution in the layer of rock to be removed has been evaluated by numerical simulation with the FLAC code (Fast Lagrangian Analysis of Continua). The correlation between the results of the cutting tests and the numerical models of the rock samples has been inferred. Starting from a conceptual model, which theoretically describes the relationship between the cutting rate and the stress, a step function was defined that indicates the ranges of stress where predefined values of the cutting rate are workable.

scholarly journals Sub-Level Stoping in an Underground Limestone Quarry: An Analysis of the State of Stress in an Evolutionary Scenario

2016 ◽  
Vol 61 (1) ◽  
pp. 199-216 ◽  
Author(s):  
Marilena Cardu ◽  
Sergio Dipietromaria ◽  
Pierpaolo Oreste
Keyword(s):  
Numerical Models ◽  
The State ◽  
In Situ Tests ◽  
Future Scenario ◽  
Limestone Quarry ◽  
Geomechanical Properties ◽  
State Of Stress ◽  
Upper Level ◽  
Pillar Structure

Abstract The aim of this study was to evaluate the state of stress of a „voids-pillar“ structure excavated by means of the sub-level stoping method in an underground limestone quarry near Bergamo (Italy). Both the current structure of the quarry (i.e. the rooms exploited till now) and a possible future scenario were analysed using the (FDM) FLAC 2D code. The quarry has been in operation since 1927; at present, exploitation is carried out underground via the sub-level stoping method. Exploitation involves two levels, with 5 rooms on the upper level and 9 rooms on the lower level. After analysing data obtained from laboratory and in situ tests carried out on rock samples and natural discontinuities, the geomechanical properties of the medium, knowledge of which is essential in order to establish the parameters that must be included in the numerical model, were evaluated. The implementation of three numerical models made it possible to study both the present conditions of quarry exploitation and the evolution of the exploited rooms, as well as a possible expansion involving a third level of rooms. Using the results obtained regarding the stress-strain present in the pillars, a potential change in room geometry was proposed aimed at reducing the stress state inside the pillars, decreasing plasticity and increasing overall quarry safety.

The State Policy towards the Homeless in Moldova between the ‘Left Hand’ and the ‘Right Hand’. The Case of Chișinău Shelter

Südosteuropa ◽  
2019 ◽  
Vol 67 (2) ◽  
pp. 175-195
Author(s):  
Petru Negură
Keyword(s):  
Homeless People ◽  
Severe Disabilities ◽  
The State ◽  
Small Scale ◽  
Left Hand ◽  
Right Hand ◽  
Binary Approach ◽  
The One ◽  
The Right ◽  
Depth Interviews

Abstract The Centre for the Homeless in Chișinău embodies on a small scale the recent evolution of state policies towards the homeless in Moldova (a post-Soviet state). This institution applies the binary approach of the state, namely the ‘left hand’ and the ‘right hand’, towards marginalised people. On the one hand, the institution provides accommodation, food, and primary social, legal assistance and medical care. On the other hand, the Shelter personnel impose a series of disciplinary constraints over the users. The Shelter also operates a differentiation of the users according to two categories: the ‘recoverable’ and those deemed ‘irrecoverable’ (persons with severe disabilities, people with addictions). The personnel representing the ‘left hand’ (or ‘soft-line’) regularly negotiate with the employees representing the ‘right hand’ (‘hard-line’) of the institution to promote a milder and a more humanistic approach towards the users. This article relies on multi-method research including descriptive statistical analysis with biographical records of 810 subjects, a thematic analysis of in-depth interviews with homeless people (N = 65), people at risk of homelessness (N = 5), professionals (N = 20) and one ethnography of the Shelter.

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