Acciones humanas sobre estructuras

En esta tesis se propone un nuevo modelo de carga para caracterizar los saltos de personas sobre estructuras y se estudia la influencia de las personas en las propiedades dinámicas de la estructura. En el estudio del comportamiento estructural de construcciones como gimnasios, salas de baile, estadios, auditorios o pasarelas peatonales sometidas a cargas producidas por un gran número de personas, se deben tener en cuenta las fuerzas dinámicas, lo cual implica el uso de modelos de cálculo más complejos y criterios de dimensionamiento con nuevos parámetros. Por ello, es necesario determinar a qué cargas van a estar sometidas este tipo de estructuras y cómo van a cambiar cuando se encuentren ocupadas por personas. En la primera parte del trabajo se presenta el problema de considerar las fuerzas dinámicas en el análisis de estructuras. Se indican los factores que influyeron en el interés por este tipo de estudios. Se exponen los objetivos de la tesis y se propone la metodología para conseguirlos. También en esta primera parte se describe el estado del arte. Se explican los modelos existentes de carga generada por saltos de personas y se hace un repaso de los principales autores y estudios sobre este tema. Por último se exponen algunas ideas sobre las modificaciones dinámicas que provoca la presencia de las personas en las estructuras. En la segunda parte de la tesis se explica el modelo de carga de saltos propuesta en este trabajo, donde se incluye una campaña de ensayos con saltos sobre una placa de carga. Se describen las estructuras de ensayo, un gimnasio y una losa que cubre un aljibe. Se detalla la identificación de las propiedades dinámicas de las estructuras, describiendo los ensayos correspondientes y los resultados de un Análisis Operacional Modal. Por último se presenta el modelo de elementos finitos de la estructura elegida para los ensayos. En la tercera y última parte del trabajo se comprueba la validez de los modelos de carga estudiados mediante la realización de ensayos dinámicos con personas saltando y la posterior comparación de los resultados experimentales con las simulaciones numéricas. Como último resultado se estudia la influencia de las personas en las propiedades dinámicas de la estructura. Para ello se utilizan los datos obtenidos mediante un ensayo con personas pasivas. ABSTRACT In this thesis, a new load model is proposed to characterize people jumping on structures and the influence of people in the dynamic properties of the structure is studied. In the study of the structural behavior of buildings such as gymnasiums, dance halls, stadiums, auditoriums or footbridges subjected to loads generated by crowd, dynamic forces must take into account, which involves the use of more complex calculation models and dimensioning criteria with new parameters. Therefore, it is necessary to determine these dynamic loads and how structures will change when they are occupied by people. In the first part of the work the problem of considering the dynamic forces in the analysis of structures is presented. The factors that influence on the interest in this type of study are indicated. The objectives of the thesis are presented and also the proposed methodology in order to achieve them. In this first part the state of the art is described. Existing jumping load models are explained and a review of the main authors and studies on this subject is done. Finally some ideas about the dynamic changes caused by the presence of people in the structures are exposed. In the second part of the thesis the proposed jumping load model is explained, including jump tests on a force plate. Test structures, a gym and a concrete slab are described. Dynamic properties identification of the test structures is detailed with the corresponding tests and Operational Modal Analysis results. Finally, a finite element model of the structure chosen for the tests is presented. In the third part of the work, the studied jump load models are validated by performing dynamic testing with people jumping and the subsequent comparison of experimental results with numerical simulations. As a last result, the influence of people on the dynamic properties of the structure is checked. For this purpose, obtained data from a test with passive people are used.

Del empirismo a la invención: cálculo y proyecto en la arquitectura moderna

El objetivo de esta tesis es poner de relieve cómo el desarrollo del cálculo de estructuras ha influido en la manera de concebir la forma arquitectónica y qué relaciones se establecen entre estructura (formal) y estructura resistente. Este modo de explicar el hecho arquitectónico, desde la relación arte-estructura, no es el más generalizado. Por lo que profundizar en él podría llegar a enriquecer la manera en la que se comprende la arquitectura. Por tanto, se parte de la base de que la técnica no es sólo un instrumento, un medio del que disponer, sino que es un proceso mediante el cual la abstracción se hace tangible. Con lo que se produce una retroalimentación entre lo universal, es decir, lo abstracto, y lo concreto, o sea, lo real. Además, esta investigación se centra en la estructura resistente, en tanto que se trata del único principio sine qua non de la tríada vitruviana. Sin embargo, no se incurre en el error de pensar que la arquitectura depende únicamente de la tecnología para su desarrollo; hay muchos más condicionantes que intervienen en ella, que van desde la expresión, hasta cuestiones sociológicas. La manera en la que los proyectistas diseñan se desarrolla en paralelo a la evolución de la técnica. Ahora bien, la meta de esta investigación consiste en dilucidar hasta qué punto la voluntad de los arquitectos e ingenieros es independiente de la tecnología. Para ello, se lleva a cabo un análisis desde dos puntos de vista. El primero plantea un desarrollo histórico de la evolución de la teoría del cálculo de estructuras en el que, a través del tiempo, se analizan las repercusiones formales que se han ido derivando de él, tanto en ingeniería, como en arquitectura. Se pretende, así, llevar a cabo una lectura de la historia para entender el presente y proyectar el futuro. La segunda visión que se plantea estudia el modo en el que los historiadores de la arquitectura moderna han entendido la noción de estructura resistente. Dado que se entiende que los críticos de arquitectura inf uyen en la manera de pensar y entender dicha disciplina. Para desarrollarla se tomó como referencia a Panayotis Tournikiotis y su libro La historiografía de la arquitectura moderna. Finalmente, se elabora una lectura transversal de ambos puntos de vista, con la intención de discernir la influencia de la técnica en la génesis de la arquitectura en el siglo XX. En ella se estudian algunos de los ejemplos más importantes de la arquitectura moderna, así como se intentan esclarecer las distintas maneras de proyectar en relación a la estructura resistente. A partir de todo lo anterior se pretende responder a la siguiente pregunta: ¿la manera en que los proyectistas plantean la relación entre estructura (formal) y estructura resistente ha sido la misma a lo largo de la Historia? Podría decirse que no. Dicha relación ha evolucionado desde el empirismo a la invención, pasando por la ciencia. En cada una de esas etapas el entendimiento, no sólo del comportamiento estructural de las construcciones, sino también del Imago Mundi, ha ido variando; lo que se ha plasmado en la relación entre estructura (formal) y estructura resistente en los edificios. RECENSIONE L’obiettivo della presente tesi è mettere in evidenza come lo sviluppo del calcolo strutturale ha inf uenzato il modo di concepire la forma architettonica e, che relazioni si stabiliscono tra struttura (formale) e struttura resistente. Questo modo di spiegare la questione architettonica, partendo dalla relazione arte-struttura, non è il più comune. Quindi, approfondire la ricerca su questo aspetto potrebbe arrivare ad arricchire la maniera in cui si capisce l’architettura. Per tanto, si parte da un principio di base ovvero che la tecnica non è soltanto uno strumento, un medio di cui disporre, ma che è un processo mediante il quale l’astrazione si fa tangibile. Con cui si produce una retroalimentazione tra l’universale, cioè, l’astratto e il concreto, ossia, il reale. Inoltre, questa ricerca si centra nella struttura resistente, in quanto si tratta dell’unico principio sine qua non della triade vitruviana. Eppure, non s’incorre nell’errore di pensare che l’architettura dipenda unicamente della tecnologia per il suo sviluppo; ci sono molti altri condizionanti che intervengono in essa, che vanno dalla espressione f no a questioni sociologiche. La maniera in cui i progettisti disegnano si sviluppa in parallelo alla evoluzione della tecnica. Tuttavia, l’obbiettivo della ricerca consiste nel cercare di chiarire f no che punto la volontà progettuale e ideativa degli architetti e degli ingegneri è indipendente della tecnologia. Per questo, si realizza un’analisi da due punti di vista. Il primo ipotizza uno sviluppo storico dell’evoluzione della teoria del calcolo strutturale in cui, attraverso del tempo, si analizzano le ripercussioni formali che si sono derivate da questo, sia in ingegneria sia in architettura. Si pretende così, realizzare una lettura della storia per capire il presente e progettare il futuro. La seconda visione che s’ ipotizza, studia il modo in cui gli storici dell’architettura moderna hanno capito la nozione di struttura resistente. Poiché si capisce che i critici di architettura inf uiscono nella maniera di pensare e capire questa disciplina. Per svilupparla si prese come riferimento Panayotis Tournikiotis e il suo libro La storiograf a dell’architettura moderna. Finalmente, si elabora una lettura trasversale di ambedue punti di vista, con l’intenzione di discernere l’inf uenza della tecnica nella genesi dell’architettura nel XX secolo. In questa si studiano alcuni degli esempi più importanti dell’architettura moderna, così come si tentano chiarif care le diverse maniere di progettare in relazione alla struttura resistente. Oltretutto quello precedente, si pretende rispondere alla seguente domanda: La maniera in cui i progettisti ipotizzano la relazione tra struttura (formale) e struttura resistente è stata la stessa lungo la storia? Potrebbe dirsi di no. Essa relazione si è evoluta dall’empirismo all’invenzione, passando per la scienza. In ogni una di queste tappe si cerca di comprendere, non soltanto il comportamento strutturale delle costruzioni, ma anche l’aspetto del Imago Mundi. Ció che é cambiato è la coesistenza tra struttura (formale) e struttura resistente negli edifici. ABSTRACT T e objective of this thesis is to highlight how the development of structural analysis has influenced the way of conceiving architectural form and what relationship exists between (formal) structure and resistant structure. T is way of explaining architecture, from the relationship between art and structure, is not the most generalized, which is why increasing our understanding of it can enrich the way in which architecture is understood. Therefore, the basis is that technique is not only an instrument, a medium to have, but rather a process through which abstraction becomes tangible. Because of this, a type of feedback is produced between what is universal, in other words, abstract, and concrete, real. Additionally, this research focuses on resistant structure in that it refers to the unique principal sine qua non of the Vitruvian triad. However, it does not err by accepting the idea that architecture depends only on technology for its development; there are many conditioners which intervene which include everything from expression to sociological issues. T e way in which builders design is developed parallel to the evolution of technique. T e goal of this investigation consists of explaining to what point the will of architects and engineers is independent from technology. For this, an analysis of two points of view is helpful. T e f rst proposes a historical development of the theory of structures in which, through time, formal repercussions that have derived from it, in engineering as well as in architecture, are analyzed. In this way, a historical reading is attempted in order to understand the present and predict the future. T e second vision that is proposed studies the manner in which historians of modern architecture have understood the notion of resistant structure, given that it is understood that the critics of architecture inf uence the way of thinking about and understanding this discipline. In order to develop it, Panayotis Tournikiotis and his book La historiografía de la arquitectura moderna was used as a reference. Finally, a transversal reading of both points of view is done with the intention of discerning the influence of technique in the genesis of architecture in the 20th century. In this reading, several of the most important examples of modern architecture are studied and an attempt is made at shedding light on the different ways of designing in relation to resistant structure. Using the previous discussion, one can attempt to respond to the following question: Has the way in which designers conceive the relationship between (formal) structure and resistant structure been the same throughout history? In fact, the answer is no, this relationship has evolved from empiricism into invention, while incorporating scientific elements. At each of the stages of understanding, structural behavior of constructions as well as that of the Imago Mundi has continually changed, which has been captured in the relationship between (formal) structure and resistant structure in buildings.

A stochastic approximation algorithm with Markov chain Monte-Carlo method for incomplete data estimation problems

We propose a general procedure for solving incomplete data estimation problems. The procedure can be used to find the maximum likelihood estimate or to solve estimating equations in difficult cases such as estimation with the censored or truncated regression model, the nonlinear structural measurement error model, and the random effects model. The procedure is based on the general principle of stochastic approximation and the Markov chain Monte-Carlo method. Applying the theory on adaptive algorithms, we derive conditions under which the proposed procedure converges. Simulation studies also indicate that the proposed procedure consistently converges to the maximum likelihood estimate for the structural measurement error logistic regression model.

Um modelo multiescala concorrente para representar o processo de fissuração do concreto.

Este trabalho propõe uma técnica de modelagem multiescala concorrente do concreto considerando duas escalas distintas: a mesoescala, onde o concreto é modelado como um material heterogêneo, e a macroescala, na qual o concreto é tratado como um material homogêneo. A heterogeneidade da estrutura mesoscópica do concreto é idealizada considerando três fases distintas, compostas pelos agregados graúdos e argamassa (matriz), estes considerados materiais homogêneos, e zona de transição interfacial (ZTI), tratada como a parte mais fraca entre as três fases. O agregado graúdo é gerado a partir de uma curva granulométrica e posicionado na matriz de forma aleatória. Seu comportamento mecânico é descrito por um modelo constitutivo elástico-linear, devido a sua maior resistência quando comparado com as outras duas fases do concreto. Elementos finitos contínuos com alta relação de aspecto em conjunto com um modelo constitutivo de dano são usados para representar o comportamento não linear do concreto, decorrente da iniciação de fissuras na ZTI e posterior propagação para a matriz, dando lugar à formação de macrofissuras. Os elementos finitos de interface com alta relação de aspecto são inseridos entre todos os elementos regulares da matriz e entre os da matriz e agregados, representando a ZTI, tornando-se potenciais caminhos de propagação de fissuras. No estado limite, quando a espessura do elemento de interface tende a zero (h ?0) e, consequentemente, a relação de aspecto tende a infinito, estes elementos apresentam a mesma cinemática da aproximação contínua de descontinuidades fortes (ACDF), sendo apropriados para representar a formação de descontinuidades associados a fissuras, similar aos modelos coesivos. Um modelo de dano à tração é proposto para representar o comportamento mecânico não linear das interfaces, associado à formação de fissuras, ou até mesmo ao eventual fechamento destas. A fim de contornar os problemas causados pela malha de elementos finitos de transição entre as malhas da macro e da mesoescala, que, em geral, apresentam diferenças expressivas 5 de refinamento, utiliza-se uma técnica recente de acoplamento de malhas não conformes. Esta técnica é baseada na definição de elementos finitos de acoplamento (EFAs), os quais são capazes de estabelecer a continuidade de deslocamento entre malhas geradas de forma completamente independentes, sem aumentar a quantidade total de graus de liberdade do problema, podendo ser utilizados tanto para acoplar malhas não sobrepostas quanto sobrepostas. Para tornar possível a análise em multiescala em casos nos quais a região de localização de deformações não pode ser definida a priori, propõe-se uma técnica multiescala adaptativa. Nesta abordagem, usa-se a distribuição de tensões da escala macroscópica como um indicador para alterar a modelagem das regiões críticas, substituindo-se a macroescala pela mesoescala durante a análise. Consequentemente, a malha macroscópica é automaticamente substituída por uma malha mesoscópica, onde o comportamento não linear está na iminência de ocorrer. Testes numéricos são desenvolvidos para mostrar a capacidade do modelo proposto de representar o processo de iniciação e propagação de fissuras na região tracionada do concreto. Os resultados numéricos são comparados com os resultados experimentais ou com aqueles obtidos através da simulação direta em mesoescala (SDM).

Dynamic investigation of an ancient masonry bell tower with operational modal analysis: a non-destructive experimental technique to obtain the dynamic characteristics of a structure

This paper shows the results of an experimental analysis on the bell tower of “Chiesa della Maddalena” (Mola di Bari, Italy), to better understand the structural behavior of slender masonry structures. The research aims to calibrate a numerical model by means of the Operational Modal Analysis (OMA) method. In this way realistic conclusions about the dynamic behavior of the structure are obtained. The choice of using an OMA derives from the necessity to know the modal parameters of a structure with a non-destructive testing, especially in case of cultural-historical value structures. Therefore by means of an easy and accurate process, it is possible to acquire in-situ environmental vibrations. The data collected are very important to estimate the mode shapes, the natural frequencies and the damping ratios of the structure. To analyze the data obtained from the monitoring, the Peak Picking method has been applied to the Fast Fourier Transforms (FFT) of the signals in order to identify the values of the effective natural frequencies and damping factors of the structure. The main frequencies and the damping ratios have been determined from measurements at some relevant locations. The responses have been then extrapolated and extended to the entire tower through a 3-D Finite Element Model. In this way, knowing the modes of vibration, it has been possible to understand the overall dynamic behavior of the structure.

Preliminary interpretation of shaking-table response of a full-scale 3-storey building composed of thin reinforced concrete sandwich walls

In the last few decades, the use of cast in situ reinforced concrete sandwich panels for the construction of low- to mid-rise buildings has become more and more widespread due to several interesting properties of this construction technique, such as fast construction and high thermal and acoustic performances. Nonetheless the level of knowledge of the structural behavior of systems made of squat reinforced concrete sandwich panels is still not so consolidated, especially with reference to the seismic response, due to the lack of experimental studies. In recent years, while various experimental tests have been conducted on single panels aimed at assessing their seismic capacity, only few tests have been carried out on more complex structural systems. In this paper, the experimental results of a series of shaking-table tests performed on a full-scale 3-storey building are presented in detail. The main goal is to give to the scientific community the possibility of develop independent interpretation of these experimental results. An in-depth interpretation of the discrepancies between the analytical predictions and the experimental results is beyond the objective of this paper and is still under development. Nonetheless, preliminary interpretations indicate that both the stiffness and the strength of the building under dynamic excitation appear quite superior with respect to those expected from the results of previous pseudo-static cyclic tests conducted on simple specimens.

Wooden cellular slabs with and without insulation submitted to fire conditions

The wooden cellular slabs are lightweight structures, easy to assemble, and with excellent architectural features, as thermal and acoustic conditions. The wooden cellular slabs with perforations are typical and very common engineering solutions, used in the ceiling or flooring plates to improve the acoustic absorption of compartments, and also have a good insulation and relevant architectonic characteristics. However, the high vulnerability of wooden elements submitted to fire conditions requires the evaluation of its structural behavior with accurately. The main objective of this work is to present a numerical model to assess the fire resistance of wooden cellular slabs with different perforations. Also the thermal behavior of the wooden slabs will be compared considering material insulation inside the cavities

Self-mode-locked vertical-external-cavity surface-emitting laser

Ultrashort laser pulses from vertical-external-cavity surface-emitting lasers (VECSELs) have been receiving much attention in the semiconductor laser community since the first demonstration of sub-ps-pulsed devices more than a decade ago. Originally relying on semiconductor saturable-absorber mirrors for pulse formation, mode-locked operation has not only become accessible by using a variety of saturable absorbers, but also by using a saturable-absorber-free technique referred to as self-mode-locking (SML). Here, we highlight achievements in the field of SML-VECSELs with quantum-well and quantum-dot gain chips, and study the influence of a few VECSEL parameters on the assumed nonlinear lensing behavior in the system. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

Análise experimental do comportamento à flexão e ligação entre painéis de lajes tipo bubbledeck

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Civil e Ambiental, 2016.

Nonlinear behavior of gelatin networks reveals a hierarchical structure

We investigate the strain hardening behavior of various gelatin networks-namely physical gelatin gel, chemically cross-linked gelatin gel, and a hybrid gel made of a combination of the former two-under large shear deformations using the pre-stress, strain ramp, and large amplitude oscillations shear protocols. Further, the internal structures of physical gelatin gels and chemically cross-linked gelatin gels were characterized by small angle neutron scattering (SANS) to enable their internal structures to be correlated with their nonlinear rheology. The Kratky plots of SANS data demonstrate the presence of small cross-linked aggregates within the chemically cross-linked network whereas, in the physical gelatin gels, a relatively homogeneous structure is observed. Through model fitting to the scattering data, we were able to obtain structural parameters, such as the correlation length (ξ), the cross-sectional polymer chain radius (Rc) and the fractal dimension (df) of the gel networks. The fractal dimension df obtained from the SANS data of the physical and chemically cross-linked gels is 1.31 and 1.53, respectively. These values are in excellent agreement with the ones obtained from a generalized nonlinear elastic theory that has been used to fit the stress-strain curves. The chemical cross-linking that generates coils and aggregates hinders the free stretching of the triple helix bundles in the physical gels.

On elimination of chaotic behavior in a non-ideal portal frame structural system, using both passive and active controls

In this paper, an application is considered of both active and passive controls, to suppression of chaotic behavior of a simple portal frame, under the excitation of an unbalanced DC motor, with limited power supply (non-ideal problem). The adopted active control strategy consists of two controls: the nonlinear (feedforward) in order to keep the controlled system in a desirable orbit, and the feedback control, which may be obtained by considering state-dependent Riccati equation control to bringing the system into the desired orbit using a magneto rheological (MR) damper. To control the electric current applied in control of the MR damper the Bouc-Wen mathematical model was used to the MR damper. The passive control was obtained by means of a nonlinear sub-structure with properties of nonlinear energy sink. Simulations showed the efficiency of both the passive control (energy pumping) and active control strategies in the suppression of the chaotic behavior. © The Author(s) 2012.

Characterization of the nonlinear behavior of a F-16 aircraft using discrete-time Volterra series

The linearity assumption in the structural dynamics analysis is a severe practical limitation. Further, in the investigation of mechanisms presented in fighter aircrafts, as for instance aeroelastic nonlinearity, friction or gaps in wing-load-payload mounting interfaces, is mandatory to use a nonlinear analysis technique. Among different approaches that can be used to this matter, the Volterra theory is an interesting strategy, since it is a generalization of the linear convolution. It represents the response of a nonlinear system as a sum of linear and nonlinear components. Thus, this paper aims to use the discrete-time version of Volterra series expanded with Kautz filters to characterize the nonlinear dynamics of a F-16 aircraft. To illustrate the approach, it is identified and characterized a non-parametric model using the data obtained during a ground vibration test performed in a F-16 wing-to-payload mounting interfaces. Several amplitude inputs applied in two shakers are used to show softening nonlinearities presented in the acceleration data. The results obtained in the analysis have shown the capability of the Volterra series to give some insight about the nonlinear dynamics of the F-16 mounting interfaces. The biggest advantage of this approach is to separate the linear and nonlinear contributions through the multiple convolutions through the Volterra kernels.

Nonlinear modelling of non-structural masonry walls under a low-intensity earthquake motion: calibration through a parametric study

This thesis aims to understand the behavior of a low-rise unreinforced masonry building (URM), the typical residential house in the Netherlands, when subjected to low-intensity earthquakes. In fact, in the last decades, the Groningen region was hit by several shallow earthquakes caused by the extraction of natural gas. In particular, the focus is addressed to the internal non-structural walls and to their interaction with the structural parts of the building. A simple and cost-efficient 2D FEM model is developed, focused on the interfaces representing mortar layers that are present between the non-structural walls and the rest of the structure. As a reference for geometries and materials, it has been taken into consideration a prototype that was built in full-scale at the EUCENTRE laboratory of Pavia (Italy). Firstly, a quasi-static analysis is performed by gradually applying a prescribed displacement on the roof floor of the structure. Sensitivity analyses are conducted on some key parameters characterizing mortar. This analysis allows for the calibration of their values and the evaluation of the reliability of the model. Successively, a transient analysis is performed to effectively subject the model to a seismic action and hence also evaluate the mechanical response of the building over time. Moreover, it was possible to compare the results of this analysis with the displacements recorded in the experimental tests by creating a model representing the entire considered structure. As a result, some conditions for the model calibration are defined. The reliability of the model is then confirmed by both the reasonable results obtained from the sensitivity analysis and the compatibility of the values obtained for the top displacement of the roof floor of the experimental test, and the same value acquired from the structural model.

Effects of Variations in Nonlinear Damping Coefficients on the Parametric Vibration of a Cantilever Beam with a Lumped Mass

Uncertainties in damping estimates can significantly affect the dynamic response of a given flexible structure. A common practice in linear structural dynamics is to consider a linear viscous damping model as the major energy dissipation mechanism. However, it is well known that different forms of energy dissipation can affect the structure's dynamic response. The major goal of this paper is to address the effects of the turbulent frictional damping force, also known as drag force on the dynamic behavior of a typical flexible structure composed of a slender cantilever beam carrying a lumped-mass on the tip. First, the system's analytical equation is obtained and solved by employing a perturbation technique. The solution process considers variations of the drag force coefficient and its effects on the system's response. Then, experimental results are presented to demonstrate the effects of the nonlinear quadratic damping due to the turbulent frictional force on the system's dynamic response. In particular, the effects of the quadratic damping on the frequency-response and amplitude-response curves are investigated. Numerically simulated as well as experimental results indicate that variations on the drag force coefficient significantly alter the dynamics of the structure under investigation. Copyright (c) 2008 D. G. Silva and P. S. Varoto.

X-ray phase measurements as a probe of small structural changes in doped nonlinear optical crystals

X-ray multiple diffraction experiments with synchrotron radiation were carried out on pure and doped nonlinear optical crystals: NH(4)H(2)PO(4) and KH(2)PO(4) doped with Ni and Mn, respectively. Variations in the intensity profiles were observed from pure to doped samples, and these variations correlated with shifts in the structure factor phases, also known as triplet phases. This result demonstrates the potential of X-ray phase measurements to study doping in this type of single crystal. Different methodologies for probing structural changes were developed. Dynamical diffraction simulations and curve fitting procedures were also necessary for accurate phase determination. Structural changes causing the observed phase shifts are discussed.