scholarly journals The use of modal analysis to examine the lattice structure

2019 ◽  
Vol 28 (3) ◽  
pp. 332-344
Author(s):  
Mariusz Żółtowski ◽  
Katarzyna Jeleniewicz
Keyword(s):  
Modal Analysis ◽  
Lattice Structure ◽  
Steel Structures ◽  
Dynamic Loads ◽  
Building Structures ◽  
Analysis Method ◽  
Safety Factors ◽  
Static Loads ◽  
Structural Types ◽  
Affect State

Steel structures are subject to large dynamic loads clearly reflected by generated vibration processes. The vibrations may affect state of serviceability of structures by lowering comfort of persons working there as well as possible reaching the level hazardous to safety of the structures. The effect of vibrations to structure is mainly manifested by additional stresses in a given cross-section, which are summed up with those resulting from static loads. The dynamic loads may cause damaging effects in buildings of various structural types or even lead to their destruction. Judging the necessity of improving the quality assessment methods of building structures for purposes of estimation of their state as well as safety factors for lattice structures, the author of this work undertook an attempt to investigate destruction process of selected object by using the modal analysis method.

scholarly journals Investigations of harbour brick structures by using operational modal analysis

2013 ◽  
Vol 21 (1) ◽  
pp. 42-53 ◽  
Author(s):  
Mariusz Żółtowski
Keyword(s):  
Modal Analysis ◽  
Operational Modal Analysis ◽  
Dynamic Loads ◽  
Building Structures ◽  
Safety Factors ◽  
Destruction Process ◽  
Static Loads ◽  
Structural Types ◽  
Fatigue Of Materials ◽  
Affect State

ABSTRACT Historic harbour brick objects are subject to large dynamic loads clearly reflected by generated vibration processes. The vibrations may affect state of serviceability of structures by lowering comfort of persons working there as well as possible reaching the level hazardous to safety of the structures. The effect of vibrations to structure is mainly manifested by additional stresses in a given cross-section, which are summed up with those resulting from static loads. Moreover often occur consequences associated with environmental conditions and fatigue of materials which accelerate destruction of the objects. Therefore the dynamic loads may cause damaging effects in buildings of various structural types or even lead to their catastrofic destruction. Judging the necessity of improving the quality assessment methods of building structures for purposes of estimation of their state as well as safety factors for brick structures (see PN-B- 03002 standard, p.3.1.3 and 4.6), the author of this work undertook an attempt to investigate destruction process of selected building structures by using the method of operational modal analysis.

Estimation of damping ratios of steel structures by Operational Modal Analysis method

2015 ◽  
Vol 112 ◽  
pp. 61-68 ◽  
Author(s):  
Fatma Nur Kudu ◽  
Şenay Uçak ◽  
Gökhan Osmancikli ◽  
Temel Türker ◽  
Alemdar Bayraktar
Keyword(s):  
Modal Analysis ◽  
Steel Structures ◽  
Operational Modal Analysis ◽  
Analysis Method

The Mechanical Properties Comparative Analysis for Socked and Non-Socketed Composite Pile

2014 ◽  
Vol 1061-1062 ◽  
pp. 748-750
Author(s):  
Heng Chen ◽  
Ke Sheng Ma
Keyword(s):  
Mechanical Properties ◽  
Comparative Analysis ◽  
Seismic Performance ◽  
Dynamic Loads ◽  
Vertical Load ◽  
Interlayer Thickness ◽  
Static Loads ◽  
Soil Stress ◽  
Composite Pile ◽  
Static And Dynamic Loads

For socked and non-socketed piles in the different mechanical behavior under static and dynamic loads, the paper use ABAQUS to model, simulate the pile , the soil interlayer thickness between the bottom of the pile and bedrock are 2m, 4m under vertical load and Earthquake, cushion cap, pile and pile soil stress situation found non-socketed piles when the soil interlayer thickness within a certain range, the composite pile small subside under dynamic, static loads, the non-socketed piles can better take advantage of the pile soil has a good seismic performance in the earthquake.

Adequate Strength for Small High-Speed Vessels

1968 ◽  
Vol 5 (01) ◽  
pp. 63-71
Author(s):  
Philip J. Danahy
Keyword(s):  
Stress Analysis ◽  
High Speed ◽  
Structural Strength ◽  
Integrated Approach ◽  
Suggested Method ◽  
Impact Loads ◽  
Analysis Method ◽  
Safety Factors ◽  
Recreational Vessels

The paper presents a method for the determination of the critical minimum scantlings for small high-speed vessels. Particular attention is given to the shell plating strength for hydrodynamic impact loads. The suggested method uses an integrated approach involving assumed loads, suggested safety factors, and preferred stress-analysis method. The stress analysis uses plastic theory based partly on the works of J. Clarkson and Thein Wah. Included in the paper is a comparison of the relative structural strength of several commercial, military, and experimental hydrofoil vessels along with a few planing boats and a seaplane hull. This shows the variation of existing vessel structures and compares them to the results obtained by the suggested method. Most commercial, military, and recreational vessels exceed the minimum scantlings of the suggested method. The most significant deviation is the hull of the seaplane:

The Specific Characteristics of Shock and Blast Impacts on Construction Sites

2021 ◽  
pp. 81-88
Author(s):  
A.A. Komarov ◽  
Keyword(s):  
Dynamic Load ◽  
Static Load ◽  
Dynamic Loads ◽  
Potential Hazard ◽  
Construction Sites ◽  
Static Loads ◽  
Equivalent Static Loads ◽  
Plane Crash ◽  
Nuclear Plants ◽  
The Impact

The practices of hazardous and unique facilities’ construction imply that specific attention is paid to the issues of safety. Threats associated with crash impacts caused by moving cars or planes are considered. To ensure safety of these construction sites it is required to know the potential dynamic loads and their destructive capacity. This article considers the methodology of reducing dynamic loads associated with impacts caused by moving collapsing solids and blast loads to equivalent static loads. It is demonstrated that practically used methods of reduction of dynamic loads to static loads are based in schematization only of the positive phase of a dynamic load in a triangle forms are not always correct and true. The historical roots of this approach which is not correct nowadays are shown; such approach considered a detonation explosion as a source of dynamic load, including TNT and even a nuclear weapon. Application of the existing practices of reduction of dynamic load to static load for accidental explosions in the atmosphere that occur in deflagration mode with a significant vacuumization phase may cause crucial distortion of predicted loads for the construction sites. This circumstance may become a matter of specific importance at calculations of potential hazard of impacts and explosions in unique units — for instance, in the nuclear plants. The article considers a situation with a plane crash, the building structure load parameters generated at the impact caused by a plane impact and the following deflagration explosion of fuel vapors are determined.

Seismic Performance Assessment of Existing Steel Buildings: A Case Study

2018 ◽  
Vol 763 ◽  
pp. 1067-1076 ◽  
Author(s):  
Luigi di Sarno ◽  
Fabrizio Paolacci ◽  
Anastasios G. Sextos
Keyword(s):  
Numerical Study ◽  
Central Italy ◽  
Steel Structures ◽  
Eurocode 8 ◽  
Building Structures ◽  
Steel Buildings ◽  
Seismic Performance Assessment ◽  
Masonry Infills ◽  
Main Shocks

Numerous existing steel framed buildings located in earthquake prone regions world-wide were designed without seismic provisions. Slender beam-columns, as well as non-ductile beam-to-column connections have been employed for multi-storey moment-resisting frames (MRFs) built before the 80’s. Thus, widespread damage due to brittle failure has been commonly observed in the past earthquakes for steel MRFs. A recent post-earthquake survey carried out in the aftermath of the 2016-2017 Central Italy seismic swarm has pointed out that steel structures may survive the shaking caused by several main-shocks and strong aftershocks without collapsing. Inevitably, significant lateral deformations are experienced, and, in turn, non-structural components are severely damaged thus inhibiting the use of the steel building structures. The present papers illustrates the outcomes of a recent preliminary numerical study carried out for the case of a steel MRF building located in Amatrice, Central Italy, which experienced a series of ground motion excitations suffering significant damage to the masonry infills without collapsing. A refined numerical model of the sample structure has been developed on the basis of the data collected on site. Given the lack of design drawings, the structure has been re-designed in compliance with the Italian regulations imposed at the time of construction employing the allowable stress method. The earthquake performance of the case study MRF has been then investigated through advanced nonlinear dynamic analyses and its structural performance has been evaluated according to Eurocode 8-Part 3 for existing buildings. The reliability of the codified approaches has been evaluated and possible improvements emphasized.

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